US1490673A - System of motor control - Google Patents

Description

April 15 1924.

E. S. MATTHEWS SYSTEM OF MOTOR CONTROL Nah 5 llllllln lllllln Ill Filed May 2, 1918 UNITED STATES PATENT OFFICE.-

B. IA'II'HEWS, 01' NEW YORK, I. I.

sYs-rmr or iro'ron coxrnon Application me! m a, 1916. Serial Io. more.

To all whom it may concern:

Be it known that I, Enwm S. Marrrmwe, a citizen of the United States of America, and a resident of the boron h of Manhattan, city, county, and State of ew York, have invented certain new and useful Improvements in S stems of Motor Control, of which the ollowing is a full, clear, and exact description, reference being to the accompanying drawings, which form a: art of this specification.

y present invention relates to the control of electric motors, and articularly to their control under all possible conditions of operation, whether the motor be 0 erated with a light or heavy load or no loa whatsoever; or whether it be overhauled and made to act as a generator either b a large or a small force, or in the case 0 alternation or fluctuation of the conditions of operation, and this invention provides a novel system of motor control.

The objects of this invention are in gen-- era] to secure increased economy of operation and greater refinement and precision of control particularly at slow speeds and at or near the point of coming to-rest of the motor and its attached apparatus, either automatically or by manipulation or by a combination of these methods.

Among useful applications of this invention are heavy gun pointing, heavy turret moving, elevator car operation, or any use of electric power where the apparatus attached to the motor is desired to come to rest accurately and precisely at some given point, either automatically or by manipulation, irrespective of conditions of loading overhaul or momentum of attached apparatus.

An exemplifying embodiment of this invention is herein shown in connection with an elevator apparatus of the well known traction type which afl'ords conditions of both dragging and overhauling variable loading and of mass momentum in stopping; and increased efficiency in the practical use of this elevator apparatus is obtained in economy of current consumption and by the precision with which the car is brought to a stop at landings avoidin loss of time in adjusting levels, which is o frequent occurrence in high speed service, as is well known. I

An illustration of the present practicp in electric motor control, the defects of which are obviated b this invention, is shown in the following ate from the recent test of a modern elevator equipment operating in a prominent building in one of our eastern cities and is as follows Current consumed to run li htly loaded car slowly when being slow down and adjusted to landing 109 amperes.

Current consumed to run same load about 600' per minute amperes.

Current consumed to rim lightly overhauled car when being slowed'down and ad'ustcd to landing 76 amperes.

urrent generated in running same overhaul about 600 per minute 18 ampleres.

S code of lightly loaded and Hg tly overhau ed car when run slowly and adjusted to landing 72 feet per minute and 153 feet per minute res ively.

Obviously this variation in speed is increased when the apparatus is more heavily loaded. 1

The want of accurate control and the wastage of current above shown may be understood by referring to the fact that the ratio of speed of a given drag load to that of the same overhaulingfi dii in the case of a motor with a 'ven shunt and series armature circuit an a constant field strength is PC 1. REHO-PTCiFL where P=the potential of the incoming line, C =the armature current and R dhe resistance in the line in series with the armature.

Hence, when as in present systems any given point of speed control calls for a certain fixed armature series and shunt circuit it becomes 11 in order to maintain even a remote correspondence between dragging and overhauling speed so as to have any certainty of centre whatever, to make the line resistance small which unavoidably causes wastage of operating current.

One object of this invention is to decrease the speed variation above referred to and thus provide greater certainty of control and at the same time to avoid the wastage of operating current above mentioned.

Another object of this invention is to keep the control of the apparatus in the hands of the operator to the maximum practicable extent in the case of a handoperated adjusting control.

Another object of this invention is to give a sufiicient certainty of accurate speed control under all circumstances so as to permit automatic adjustment of the apparatus to a fixed point with a high degree of precision, and to provide an apparatus in which both manual and automatic control may be employed together.

Other features and objects of this invention will become manifest to those skilled in the art as its typical embodying instrumentalities and its operation are later explained and its novel features are pointed out in the claims.

A brief general description of the apparatus herein shown, as embodying this invention, is here given for facilitating the apprehending of its details hereinafter more fully described; in which Anelevator car and its counterweight are driven directly from a slowspeed armature in the well known manner of the traction elevator.

The motor is a direct current reversible shunt wound motor, the highest speed of the apparatus being attained by a weakenin of its field.

A friction brake is employed to hold the apparatus at rest and to stop it after electrical conditions for its slowest speed have been established.

Two sets of speeds are provided, viz, running speeds, and adjusting speeds.

A manual controlling switch is employed having in the case of this typical illustration two runnin speed points of control and three adjustm speed pointsof control, and

iving control of the direction of motion. bviously the number of speeds and their controlling points in the operators switch maybe varied, if desired V In addition to this and cooperating with it an automatic stop control is provided to bring the apparatus to -rest in this case at either of two fixed points viz, the upper or the lower terminal landings.

The apparatus is started and brought to its various running speeds .in this embodiment of the invention by the employment only of series armature resistance and variation of field strength.

The adjusting speeds in this embodiment of the invention are obtained only by the employment of a fixed armature series resistance and a variable shunt resistance the latter being doubly variable; both from the particular speed adjusting point of control employed and 'from the armature current conditions.

A comparatively weak shunt field is con: stantly maintained upon the motor which is .switches, which, while preventing automatically strengthened when the motor is started, weakened at its highest speed and automatically strengthened whenever an armature shunt circuit is in action whether the armature is or is not connected to the main line.

The armature starting resistance, which is a series resistance, is cut out gradually, upon starting the motor, by a series of switches which short-circuit sections of this resistance successively as the growing counter-'eleotromotiveforce of the accelerating armature develops, finally removing all of it; at which time the elevator assumes its slowest running speed.

The armature adjusting shunt resistance is governed by two sets of switches one set being operated by circuits from the adjusting speed contacts of the control switch which bring this armature shunt resistance into action only when a certain fixed Series armature resistance-has been put in circuit, and which permit certain of this shunt resistance to come into action; the extent of which is automatically modified bythe polarized regulator which governs the other set of switches acting upon this resistance.

An auxiliary switch, retainin the manual controlling switch contacts w ich' actuate the reversing switches for use during the adjustment period, and obviatingall -waste of current throu h the armature shunt circuit in starting t e motor, is also provided in this embodiment of the invention.

The reversing switches make and break the circuit of the main line through the armature and govern its direction of rotation and the operatin circuit of these switches is provided wit automatically actuated too sudden reversal of the armature circuit, yet keep a reversing switch'always at the operators disposal.

The exam lifying structure herein shown is illustrate by a diagrammatic drawing, the usual oonventionalities being therein employed, and this structure will now be described more fully in detail, reference being had to the drawing, in which Current supply enters the apparatus at the signs and at the'middle left hand top and bottom of the drawing.

1Q represents a motor armature with a sheave concentric therewith and directly .attaehed thereto over which passes a wire cable 11 attached at one end to an elevator car 12 and at the other end to a counterweight 13, the two latter being driven from the arms.- ture by friction between the wire cable and the sheave in any of the well known traction manners.

The armature brushes are shown at 1i and 15.

A friction brake is shown at 16.

The hand control switch is shown at the shown on-the left hand of this switch are for upward motion of the elevator and those at the right hand for downward motion;

vreversing switch respectively according to the direction of motion desired; andfurther since the o ration of these reversing switches is t 0 same except that they reverse the direction of the current through the armature, only one set of these control circuits will be designated by numbers and described in detail and the accompanying operation of the apparatus described; thus avoiding complicating thedrawing by an excessive number of reference numerals, although the com lete circuits are shown on the drawing an may be traced through, if desired.

The control circuits for upward motion will be thusused for the purpose of this descri tion. I

A circular segmental contact strip 21 is swung about the center 22 manually by the handle 23 engaging the speed point contacts 24 and 25 for startin the apparatus and for producing low an high running speeds respectively and contacts 26, 27 and 28 for producing adjusting speeds; the first motion of tlie segment 21 over contacts 26, 27 and'28 in starting the apparatus producing no effect beyond the removal of the armature shunt circuit; whereas later, after the apparatus has been started, the release of contacts 26, 27 and 28 introduces and modifies the armature shunt circuit for the purpose of adjustment, as will later be described in detail.

The apparatus will now be described in its operation of upward'motion during its starting, speed adjusting and stopping from the manipulation ofthe operators switch and its stopping from the automatic stop device mentioned; and in this connection its circuits and instrumentalities will be described in detail.

During the period of rest but one circuit is in operation, viz, that which maintains its weakened field circuit which starts from main 17 at 29 traverses conductor 30 diverging at point 31 and passing through conductor 32 resistance 33 and shunt field 34 reaches the main 36 at 35.

In starting the apparatus no immediate eifect is produced by the first closing of contacts 19, 28, 27 and 26 by the operators control switch as the circuit from 28 is open at point 42 after traversing conductor 281, and the circuit from 27 is open, including open point 38, after traversing the condoctors 271, automatic stop contact 272, 271 coil of switch 273, conductor 242627 and 37;and the circuit from 26 is likewise open at the same point after traversing similarily numbered paths and the common conductor 242627. 4

The circuit from running speed control point 24 of the operators switch through coil 241 would also be open at the same'point where it not for the fact that when speed point 24 is reached by the operators switch the up reversing switch 39 [8 closed, which closes contact 38, and starts the apparatus in the following manner.

supply from main 17 through conductor 18 contact 19 se ment 21 contact 24 concluctors 241, 244 lower coil of auxiliary switch 40 to the supply line 36 thus actuating auxiliary switch,40 closing the follow up spring contacts 41 and 42 with the plate of the switch, which plate comprises two insulated halves connected by conductors to reversing switch control contacts 28' and respectively of the operators switch thus comp eting in this case a circuit 17, 18, 19, 21, 28, 281, 42 through conductor 283 the actuating coil of up reversing switch 39, conductor 284 the back contacts of down reversing switch 43.to suppl main 36.

The potential now upon t 1e armature causes the holding coil 451 of auxiliary switch 40 to retain its plate against follow 'up contacts 41 and 42 as long as any appreciable potential remainsu on the armature; (circuit from one en of coil 451 through 171 to brush 14, and from the other end of coil through 362 to oint 493 conductor 361 resistance 44 an 172 to brush 15) and when this potential vanishes to still keep these contacts closed until the vacuum air dash pot 461 has allowed them to separate; this dash pot being constructed in a well known manner so as to allow prompt closing action of switch 40 but to retard its opening, although other forms of retarding apparatus may be used, if desired; thus retaining the operators reversing switch contacts in service as long as they can be required for adjusting purposes.

The closure of reversing switch 39'closes contact 38 with the supply main 36 thus completing the circuits of o .rators switch contacts 24, 26 and 27 throng all the actuatingcoils of the armature shunt circuit controlling switches 243, 263 and 273 as will readily be understood from the preceding tracing of the typical circuit at speed point 27 up to the int 38, which at that time was open.

Thus the armature shunt circuit is immediatel removed at the outset of the starting o the apparatus. y

, he energizing of the conductor 37 also causes two other operations incident to .the starting of e apparatus to be effected, viz the removal of the friction brake 16 and the strengthening of the motor field 34.

The former takes place through the action of a circuit through the actuating coil of the brake proceedin from supply at conductor 30 at point 3 3 and passing through conduct/or 371 now bearing the potential.

The latter occurs as the resultof a circuit from the end of conductor 30 through conductor 376 the actuatin coil of field control switch 45, resistance $75 and conductor 374 to conductor 37 thus actuating switch and short circuiting field resistance 33.

The armature resistance 44 (series resistanfie only being in circuit) is now automatica y short-circuited gradually; for the 0 ening of switch 243 (armature shunt ma er) closes a circuit at its lower contacts from brush 14 conductor 171, 173 through lower contacts of'sw'itch 243 conductor 174 through all the actuating coils-of the series- resistance controlling switches 175, 176, 177 and 178 common conductor 179 conductor 172 to the op ite brush of the armature 15.

ese coils and switches respond to the rising' armature ntial successively in the or er of their esignating numbers in a well known manner gradually short-circuiting the armature series startin resistance 44 until the final action of switch 178 has removed it entirely.

It will be noted that this armature series starting resistance cannot be removed until the armature shunt circuit is broken.

The elevator now attains its slow running speed.

If the attempt should be made to suddenly reverse the apparatus by reversing the operators switch so that it drops contact 19 and enga 51 or down motion) the ap ratus will not reverse until its speed is su ciently diminished so that reversal may be fi'ccted without throwing undue current upon the armature, which is accomplished in the following manner I-- It has been mentioned that the circuit for the actuating coil of the up reversing'switch 39 which has been operated in this description passes through the back contacts of down reversing switch 43. So likewise the actuating circuit of the down reversing switch 43 passes through the back contacts of up reversing switch 39 and these contacts have been opened when the up reversing switch 39 contact 20 and speed contact or amoeba was closed by the raising of plate 46 away from these contacts.

This plateis loose 'upon spindle 47, bein raised by the head 48 of said spindle, an now having been raised up to within the influence ofmagnet 49 (which is preferably provided with iron return magnet line flux circuit enclosure as shown in the drawing in order that its magnetic force may be concentrated and intensified) it will remain held there by even a slight potential upon the armature thus keeping the actuating circuit of the down reversing switch 43 broken until the armature potential has decreased sufficiently to permit of its reversal even if rcversing switch. 39 be opened.

The circuit of this holding coil of magnet 49 proceeds from the lower end of the coil through conductors 491 and 171 to brush 14 and from the upper end of the coil through conductor 362 joining conductor 361 at point 493 thence through resistance 44 and conductor 172 to brush 15.

The broken actuating circuit of the down reversing switch 43 proceedsifrom main 17 conductor 18 contact 29 segmental plate 21 contact 50 conductor 501 ate of switch 40, contact 41 conductor 503 t rough actuating coil of switch 43 conductor 504 to the lower broken contact of switch 39; which contact will become closed and complete the actuating circuit of switch 43, as soon as the I armature ntial has sufliciently fallen, by the dnoppmg of plate 46 from the holding coil of 49 whereupon the actuatin circuit of the down reversing switch 43 wil be completed to the main 36 in an obvious manner, and rmit reversal to take place.

Since the similar plate governing the actuating circuit of the up reversing switch 39 (operated in this illustrative operation-see circuit previous] traced) has not been brou ht within 0 influence of its holding coil iecause the down reversing switch to which it is attached has not been operated, it is obvious that there will be no interference with the operators control of the actuating circuit of the u reversing switchand even if he should r'op this switch an thus permit it to open he is enabled to pick it u again for use in adjusting the apparatus if he should so desire.

Thus the operator has a reversing switch always at his dis l for urposes of adjustment, and he iia i fiorded maximum control of the apparatus as far as is consistent with safety and economy of operation.

If the higher running up speed of the apparatus is desired the operator swings his controlling switch sufiiciently to engage contact 25 of this switch whereupon the current supply of this switch (already understood) passes through conductor 251 the up per now closed) contacts of switch 178 conweakened V tinuin on conductor 251 .to the point 252; thus s ort cimuiting the actuating coil of field control switch 45 upon the main, as will be readily understood from'the circuit of this coil formerly traced. This causes switch 45 to open introducing the resistance 33 into the field circuit; thereby weakening the strength of the field and accelerating the. apparatus to the higherrunning speed.

had quickly moved-his control switch to the high speed point it would have been iminlains broken at the upper contacts of switch 1 8.

Retracting the operators switch so as to open high running s contact 25 will slow the car down to its ower running d by causing the field strengthening switch tov close and cut out the resistance 33 from the field circuit in a manner that is now obvious.

Further retraction of the operatorls switch, so as to additionally open running speed contact M, but retaining adjusting s eed contact 26 in use, will slow the car own still further bringing its speed down to the rate of-its highest adjusting speed for the armature shunt circuit will now be brought into action, and the armature series resistance will now be introduced, in a man ner now readily understood, for

4 v The opening of control circuit 241 by this movement of the operators control switch, de energizes the actuating coil of the auxiliary switch 40, but this switch still remains closed through the action of its holding coil as is obvious from the previous description -of its operation and its circuits.

Additionally the actuating coil of switch 243 (armature shunt maker) is de-energized causin this switch to open its back contacts thus e-ener ing all the series resistance control switc es 175, 176,, 177 and 178 (as will be understood from the previous description of their circuits and operation), causing all of them to open thus introducing the armature series resistance 44 into the circuit of the armature with the main lin-.

At the same time an armature shunt circult is made at the up 1' contacts of this switch 243 through brus 14 conductors 171, 173, upper contacts of switch 243, all of the armature shunt resistance 51, 52 and 53 (as switches 263 and 273 are now open) and conductor 54 to brush 15 {except as to the eatent of the segments 51, 52 and 53 employed, which is modified by the action of switches 55 and 56 that govern the working portions of these shunt resistance. segments.

In the position of the apparatus shown in It will be noted that in case the operator the drawin (which is that of medium regulation as W1 1 be later fully explained) it will be noted that switch 56 being open exercises no efl'ect upon any portion of armature shunt resistance sections, but that switch 55 being closed short cirsuitsa portion ofeach of the segments 51, 52 and 53 by theclosure of its contacts'upon conductors 601 and 611 leading to points 60 and 61 in the shunt resistance respectively andthe additional conductors 591 (leading to point 59 of section 51), 621 leading to point 62 of section 52) and 641 leading to point 64 of section 53) thus cutting out of service the portions 59--60 of section 51, 61-62 of section 52 and 61-64 of section 53, thereby reducing the worln'ng shunt resistance to that included between points 57 and 59, 60 and 62, 66 and 64..

This action of thee 'paratus, as shown by the position of switc es 55 and 56 in the drawing is that of medium armature shunt resistance and will-bethat' occurring when the armature is being traversed by no'current or by a small current resulting either from dragging or overhauling load as will be understood from an examination of the operation of these switches 55 and 56, which will now be explained. I

Obviously if switch 55 were to be opened by the energization of its actuating coil its short-circuitmg efl'ect as shown in the ition of the drawing would cease and al the armature shunt" resistance comprising the total' resistance of sections 51, 52 and 53 would be in circuit which would-give the action of maximum armature shunt resistance occurring when the armature is traversed by a considerable current resulting from a dragging load asw'ill-laterbe made evident by the elucidation of the actionof the polarized regu ator in controlling switches 55 and 56. y

Also obviously-if switch 56 were to be closed by the ener 'zation of its actuating coil the armature s unt resistance would be short circuited stillfurther than is shown in the position of the drawing; for section 51 would lose portion 5860; section 52 would lose portion 6163; while section 53 would lose portion 61-65; thus establishing the condition of minimum armature shunt resistance occurring when the armature is traversed by a considerable current caused b overhauling load as will be fully exp ained later.

In this case int 58 is short circuited to 60 through con uctors 581 and 601; point 61 is short circuited to 63 throu h conductors 611 and 631; and int 61 is s ort circuited to point 65 throng conductors 611 and 651,

the sections of armature shunt resistance 51, 52 and 53 is separately governed as to working portions thereof by the action of switches 55 and 56 so that a proper. governing effect is ensured whether one, more, or all of the sections 51, 52 and 53 is brought into action bythe' operato'rs control switch or by the automatic stop device.

In the examination of the operation of the olarized regulator to follow, it will also Be noted that regulating effect is produced in this exemplification of the invention by the action of the current traversing the armature so that the regulation is equally effective and sensitive whether'the potential of the armature be hi h or low and consequentlyirrespective o the number of sections or the quantity of armature shunt resistance in service or the operators speed point of control employed or the degree to which the automatic stop device may have been operated; so that t e regulation eontinues effective during manual or automatic slow down either-preparatory to a stop or in and during the use of the adjusting speeds however low the speed of the apparatus may be brought.

The common drain conductor of the actuatin coils of switches 55 and 56 is found in con uctor 5556 which joins the main at 5557. A supply of actuating current from the main 17 at oint 29 1S afiorded the actuating coil of switch 55 through conduc tors 30, 553 switch 552 of the polarized regulater 67 whenever this switch is closed and conductor 551; while a similar su ply is afforded the actuating coil of switc 56 from point 29 through conductors 30, 563, switch 562 ofthe polarized regulator 67 whenever this switch is closed and conductor 561; hence whenever switch 552 is closed, switch 55 will be actuated and its contacts opened; and whenever switch 562 is closed switch 56 will be actuated and its contacts closed.

The polarized regulator, which will now be described, is actuated by an electric magnet 68 hereinafter designated as the armature magnet, ener' ized by a coil 69 in the armature circuit w ich coil in this exemplification of the invention forms a part of armature conductor 171.

Hence" the polarit of this armature mag- 'net 68 is determine by the direction of the armature current, i. e. by whether the current is toward or from the armature; while its power is dependent upon the amount of such current and when no current is passing throu h the armature, the armature magnet 68 will not be energized.

Two other coils are shown upon this armature magnet, which are wound at pro r polarity, being placed in series and in t is case closed circuited through an adjustable resistance at 71.

These coils are deadening coils and their oilice is to revent too sudden a response of the magnetism of 68 to peaks of current instantaneously occurring and but momentary in duration when armature speed conditions are abruptly changed, and thus to avoid super-sensitiveness in the action of the regulator.

Other retarding means either electrical or of deadening; although to avoid unneces-' sary action and wear of parts .it is preferred to use-a deadening feature."

This electro-magnet 68 is preferably provided with an outside enclosing iron cylindrical shell or bars 72 for the return circuit of magnetic lines and this shell is rovided with inner re-entrant bosses 73 and 4 in order to ensure uniformity of magnetic field and distribution of magnetic flux between the ends of the inner core of the armature magnet and these bosses 73 and 74; and the ends of 70 project suitably beyond the enclosing coilsso as to avoid any bunching or undue concentration of magnetic lines in any portion of their path under any circumspaces the actuat- The switches 552 and 562 are shown as obtuse angled elbow-switches swinging about the pivots 75 and 76 respectively and in the drawing each is shown in open position with their actuating electro-ma nets and coils 79, 80 and 81, 82 respective v in a position of repose with each of t ese electromagnets close to its re-entrant boss 73 and 74 respectively, being held in this position by some action of gravity and by the tension oftheir' regulating springs 77 and 78res ectively. Obviously either switch will be c osed whenever the attraction of the armature magnet drawsits respective actuating ma net to itself.

In this em iment of the invention all the magnets of the polarized regulator become energized as soon as current is turned upon the armature, and remain operative as long as the armature is electrically excited.

Since the energizing coil of the armature 'coil through a flexible conductor 83 while .vided with flexible conductors '85 an LOCLWS The circuit of actuating coil 80 joins con-' ductor 361 above the right hand end of the coil 82 is provided with a similar flexible conductor 84 also similarly joining conductor 361.

The other ends of these coils are also ro- 86 joining a common conductor 87 which joins 171 through points 88 and 89. v

1 If it is desired to retain full otential upon the actuating coils 80 and 82 a duringthe complete riod of dynamic braking (after the reversing'switch has been dropped) their conductors are su plied with a reversible full line potential t rough contacts attached to hold' on plate 46 of the up reversing switch :iiid its companion plate of the down reversing switch in a similar manner, now easily understood, instead of directly from the reversing switch itself as herein illustrated for the sake of sim licity.

The energizing coils of actuating magnets 79 and 81 are oppositely wound so that each presents the same polarity toward the armature magnet and each to the other. All polarities of all these magnets are reversed upon reversal of the apparatus. Thus the inductive efi'ect of magnetic lines arising from the actuating ma ets alone and solely, since they are of equa strength, practically vanishes.

The action of governing the speed of the apparatus while its adjusting s contacts are in use will now be exp ained by the aid of a concrete illustration whereupon the mode of 0 ration of the apparatus in that respect Will become obvious.

.Its operation will be examined when the operator has slowed down to adjusting speed contact 26, previously mentioned, the effect of which has been heretofore-described with the exce tion of the verning of the extent oft e armature s unt circuit through the action of the polarized regulator.

In the upward motion of the car the actuating magnets of the polarized to later will be supposed to present, each 0 them, an N pole to the armature magnet and to each other, While the armature magnet is so wound as to present an N pole to actuating magnet 81 of switch 562 and an S ole to actuating magnet 79 of switch 552 w ile its armature is receiving current or working under a dragging load ;and an S' pole to magnet 81 of switch 562 and an N pole to 66 actuating magnet 79 of switch 552 while generating current or working under an overhauling load ;-'while under conditions of 'no current passing through the armature or working with a practically balanced load,

the armature magnet will not be energized.

The condition of balanced loading will first be examined as that is the condition represented in the drawing.

While so running, the armature magnet 68 is de-energized and neither actuating magnet 79 or 81 will be moved, the switches 55 and 56 will both be unactuat-ed, as shown in the drawing, and the medium amount of armature shunt resistance emdployedwhich has been heretofore describe in detail. At the instant the shunt armature resistance is introduced a peak of generated armature current will occur, due to the slower speed conditions thus imposed, but it will, in the case of small momentum, be nearly instantaneous; as it is due solely to the momentum of the a paratus there being no actual overhauling oad present to pro duce any generative eflect;-and the polarized regulator-as usually adjusted will not in such case respond to-it. It will, however, as usually adjusted, respond to large mo mentum; armature magnet 68 being temporarily energized by the generated current, 95

thus momentarily closing switch 56, its efl'ect being merely to check excessive momentum; for the generated armature peak current will suddenly fall as the motor slows down,

de-energizing magnet 68, thus opening switch 56, and so bring the apparatus automatically. to the position shown in the drawing, which provides a standard speed responding to the use of adjusting speed contact 26.

Now in casethe apparatus has been operating under a considerable overhauling load, magnet 81 has been actuated, closing switch 562, energizing the actuating coil of switch 56 thus closing the latter establishing the condition of minimum armature shunt resistance as will be understood from previous explanations; and the tendency of the apparatus to assume unduly rapid overhauling speed during the use of adjusting speed contact 26 will be corrected, and the apparatus brought to standard speed,

If, 'on the contrary, the a paratus has been operating under a considerable dragging load, magnet 79 has been actuated,

closm switch 552', energizing the actuating coil 0 switch 55, thus openin the latter establishin the condition 0 maximum g. armature s unt resistance aswill also be readily understood from tions; and the tendency of the apparatus to assume unduly slow draggin speed during the use of speed contact 26 Wlll be corrected,

revious explanaand the apparatus brought to standard speed.

If excessive momentum is present when an adjusting speed contact is brought into usewhile a dragging load is slowed down,

switch maybe closed for an instant, and

in the case of reat excess momentum switch 56 may also closed for an instant, but these effects will be exceedingly short and will merely aid in checking the momentum, in which the dragging load itself will assist; and upon this momentum being checked the apparatus will automatically again assume the position of maximum shunt resistance.

This feature of the action of the polarized regulator being understood it is also now obvious that when adjustin speed confacts are abruptly advanced to higher speed, and the armature draws considerable current from the line, the higher armature shunt resistance circuits may be momentarily established; as for illustration, the switch 55 will in some cases-open its contacts and thus aid the apparatus in picking up or accelerating the load promptly; after which the proper equilibrium con tion is automatically efi'ected.

The polarized re later thus aids in accelerating or retarding the speed of the motor moved apparatus, and also establishes a standard speed for a given speed control contact.

In the embodiment of the invention herewith illustrated two standardizations of ad- 'usting speeds are shown independent of the alanced 'loadstandard adjusting s ips-d? one for dra ging load and one for over trated; but responding to the de ing load;' ut obviously standard speeds may also be provided for light and heavy loading, if desired, for additional switches may be employed, similar to and operating in the same general manner as those illusi e o drag ing or overhaulin load so t at the spee variation during the use of adjusting speed contacts may be reduced to any limit desired; and economy of operation increased.

The construction herein shown is, however, by judicious proportioning of resistance and roper ad'ustment'of res nsiveness, capa le of ful lling nearly al practical requirements.

A slower adjusting s d is obtained b still further retracting .t e operatorsswitc so as to open contact 26 (the o ration of the apparatus accompanying t e employment of which as an adjustin'g'speed control contact has been described) and retaining in service contact 27 and 28 as adjusting speed contacts.

In this case switch 263 of the armature shunt resistance is closed by the de-energization of its actuating coil thro h the sevstance of its supply current w ch in derived from contact 26 of the 'operators switch now opened.

This short circuits section 51 of the arma- 53 alone in service, the workin amount of which sections is governed by t e polarized regulator as is now understood, from the previous tracing of the circuits involved; thus diminishing the amount of armature shunt resistance employed while the armature series resistance remains unchanged and establishing a slower adjusting standard speed of the apparatus than that which was allorded while the higher adjusting speed contact 26 was in use. 1

Still further retraction of the operators switch so as to employ only contact 28 will cause a still further'reductlon in the standard adjusting speed of the apparatus, bringing it in this case, to'its slowest adjusting speed that employed preliminary to making a stop.

In this operation switch 273 is closed in a manner exactl similar to the closin of switch 263 just a ove described and sections 51 and52 of the armature shunt resistance are now short-circuited leaving in service only working segments of section 53, thus again dimin shing the armature shunt resistance, while the armature series resistance remains unchanged thus-establishing the slowest standard adjusting speed; for the reversing switch still remains closed through the action of contact 28 of the operators switch the actuating circuit of which has'been heretofore traced and described.

The circuits from the operators control switch employed for obtaining these slower adjusting speeds are shown in the drawin butwill not be traced in detail as they wi l be readily understood from the tracing of the circuits employed with adjusting speed contact 26 to which they are similarand similarly numbered; contact 26 controlling switch 263 and contacts 27 controlling switch 27 3, while -contact 24 controls switch 243,-which latter makesor breaks the armature shunt resistance circuit.

Continued retraction of the operators switch which opens contactv28, and brings that switch to the position shown in the drawing,deprives the actuating coil of the reversing switch of its-current (as will be friction brake 19 (see its circuit previously traced) thus applying the friction brake; while working segments of section 53 of the armature shunt resistancebein still in circuit act as a dynamic brake t as bringing the apparatus to a stop.

It will now be obvious to those skilled in at the same time adjusting speed of the apparatus may be made controllable and much the art that by the-use of this invention economy of operation may be preserved and its employment is obviously not limited to this particular manner of automatic stoppm T e apparatus for properly severing the control circuits so as to ring the elevator apparatus herein illustrated to rest accurately, at its upper and lowerterminals of travel, is diagrammatically and conventionally shown in the drawing, beneath the operators switch, in order to avoid complicating thecircuits and to facilitate the reading of the diagram. a

The stop from upward motion will be considered in detail, as the downward stop is similar thereto, and hence will be easily understood' without detailed explanation after the upward sto is described.

The three prongs elbow lever is located on the elevator car and swings about the pin 91 fixed thereon, automatically coming to the osition' of rest or no control, as

.shown in t e drawing, when between termin'als and outside of the influence of cam surfaces 92 and 93 which are respectively situated near the upper and lower landings respectively and within the limits of car travel.

As the car approaches the upper landing the cam 92 ngages the roller 94 upon the pin 95 at or near the end of the pendant arm of the elbow lever 90 and the continued upward motion of the car causes cam 92 to push the pin 95 to the left (as shown in the drawing) thus swinging elbow lever 90 and raising the arm 101, which engages successively the pins 96, 97, 98, 99 and 100; thus successively opening the up motion contacts 252, 242, 262, 272, and 282; the timing of these successive engagements being preferably adjusted so as to cause the apparatus to assume its standard adjusting equilibrium speed for each severed circuit before the next succeeding circuit is opened and in any event to assume its lowest standard adjusting speed while contact 282 is closed and'just before its 0 ning causes the line current to be severe from the armature and stops.

the apparatus.

The lowest standard adjusting speedthrough the use of contact 282) bein low, t 1e momentum of the apparatus is si ht; hence upon severance of the armature ine circui by the opening of contact 282 caused by the continued motion of the car' and the consequent applying the dynamic and the friction brakes, the apparatus is brought to an accurate stop.

A special adjustment of the working segments of section 53 of the armature shunt resistance (which is the only so out .in use preparatory to a stop) is ma e by in-, creasing the relative proportion of the resistance of segment 53 short-circuited by opening of the reversing switch switches 55 and 56, so that the speed of the d tagging load is somewhat greater than that of t e overhaulin g load; and consequently the influence of the load to either diminish or prolon (as the case may be) the distance traveled by the apparatus in coming to a stop when the armature circuit is severed, is

compensated. However, when additional segments of the armature shunt resistance are employed, the amounts of working sistance are so proportioned that the speeds of the dragging or the overhauling .load are equally affected, being brought to practically the same standard speed."

Additional dynamic braltingforce, be-

yond that afforded by segment 53 of the armature shunt resistance, may be employed, if desired in various manners, as for illustration;hy placing an additional segment of armaturefshunt resistance in parallel with 53 wheneverthe reversing switches are open, and accurate resu lts are obtained by causing the working am unts of all or any dynamic braking resistaiioe to be governed through switches 55 and 66 or other similar switches (after the main line current is severed from the armature) through the polarized regulator-in the manner heretofore described; but this will seldom be desirable on account of the low speed obtained from the lowest speed adjusting control contact.

enever armature shunt resistance is in service, whether for speed adjusting or for dynamic braking, the current traversin this resistance passes through actuating coil 102 of field strengthening switch 103 ascoil 102 forms "a part of armature shunt conductor 173 causing switch 103 to be closed during the armature shunt action thus ensuring a strong field upon the motor even after switch 45 has been caused to open by the opening but also to the electrical repulsion of the re spective larities of their actuating magnets and whenever electrical conditions cause either of the switches to come into action, the other switch is withheld from ac-' tion by an increased repulsion as well as by the usual mechanical means.

It will also be seen that the action of these switches is equally positive when the potential of the armature is low (at slow speeds) and when consequently a rise or fall of a few volts potential causes a large proportional variation in speed thusensuring positive control of the slowest speeds of the apparatus. This arises from causing the standardization of speed to be effected from the actionof the armature current and not from the otential present at the armature brushes, w ich potential, on account of resistance control eilectedby-current actuated -mea1is, is kept substantially constant for any given s eed condition as called for by the particu ar adjusting speed contact which is m use this potential being fixed for each adjustln slpeed contact according to the speed w ic such contact is desi ned to efiect. Since proper regulative modi cations of armature resistance are fixed by current conditions (irrespective of whatever adjusting speed contact may be in use) no rear rangement of these regulative conditions becomes necessary when different potentials are applied to the armature by.changing the speed contact in use. 1

While the motor-is running from the use of the running speed contacts, with no resistance in its armature circuit .it exemplies a motor (electrically considered) operating with a circuit imposing substantially fixed speed. condition; for but slight variation in its s is produced by mechanical force applied to its armature to hinder or to help its rotation, althou h current conditions are varied by such a p ication. However, when operatingfrom t e use of its adjusting speed contacts, without the potential regulator and its connected instrumentalities, it exemplifies a motor (electrically considered) 0 crating in a circuit imposing variable spees conditions for in this case on account of the presence of armature resistance in its circuit, its

speed and current conditions are both materially varied by the application of mechanical force to help or to hinder armature rotation, and this is accompanied by a variation in armature potential.

The effect of the polarized regulator and its connected instrumentalities is to vary the resistance in a variable speed im osing circuit, according to the amount an direction of current passing through the armature and thereby control, within comparatively narrow limits, the variation of the armature otential; and to do this with certainty 1ndependently of this armature potential,

whether it-be. hi h (in the case of the high adjusting speeds or low (in the case of t e slow ad usting speeds). Further illustration of the independence of this control from the armature potential is seen when it causes that potential to become lower in the case of action of the m'otoras a d namo and it is generatin current, than w on acting as a motor an it is receiving current from the supply, as shown when the resistance'segments of section 53 areadjusted to roduce compensated stoppin as previous y men'- tioned; thus arbitrari y reversing the potentials normally developed in a circuit of this character.

Also further on account of the nature of the magnetic circuit employed in the'polarized regulator, which avoids inductive concentration of magnetic lines these switches 552 and 562 will romptly release-and automatically open w enever the electrical condition of the armature calls for such action; the mutual repulsion of their res ective actuating'magnets contributing to t is result.

In the embodiment of the invention herewith illustrated a reversible motor is shown, and the actuation magnets 80 and 81 are polarized reversibly by the electric current energizing them, according to the direction of armature rotation.

If a motor revolving in one direction only is employed, reversible polarization of these actuation magnets becomes unnecessary, and in such C8SB, lf-deSlI'ed, they may be made of hard steel permanently polarized and of a suitable fixed strength.

This construction embodying this invention herewith illustrated contains other novel and useful. features in addition to' the polarized regulator which latter, as well as other features of the invention, may be employed in connection with other arrange- .ments of circuits, switches, field, armatures,

and associated and cooperating parts and instrumentalities and- Many variations in the construction and details and the location and relative arrangement of parts would readily suggest themselves to those skilled in the art to which this invention relates and still fall within the spirit and scope of my invention; hence I do not desire to be limited to the exact construction herein set forth; but having explained the principles of my invention, and a preferred form 0 in it, and-- avin described the function, purpose and mo e of operation of such apparatus what I claim as new and of my own invention, and desire to secure by Letters Patent of the United States is,

1. The combination of a motor, conduc tors carrying current therefor, a circuit for said motor including means whereby varia-' ble speed conditions are imposed thereupon,

apparatus embodyand automatic. means constructed and ar ranged to vary said circuit oppositel so as to raise or lower the potential applie to the armature of said motor in accordance with increase or decrease of armature current flow.

2. The combination of a motor, conductors carrying current therefor, a circuit for Said motor armature containing armature series resistance and armature shut resistance flow through the armature of said motor and indepcndentl of the armature potential.

4. The com ination of a motor, conductors carrying current therefor, a circuit for said motor armature containing armature series resistance and armature shunt resistance therein, and automatic means constructed and arranged to oppositely vary the resistance of said circuit in accordance with increase or decrease of armature current flow and independently of the armature poten- I tial.

5. The combination of a motor, conductors carrying current therefor, a circuit for said motor armature containing series resistance and armature shunt resistance therein, and automatic means constructed and arranged to oppositely vary the resistance of the shunt ortion of said circuit in accordance with increase or decrease of armature current flow.

6. The combination of a motor, an operators switch for starting and controlling the speed circuits of the motor, conductors carrying current for said motor, conductors carry-' ing current for said operators switch, a speed circuit for the motor armature supply which contains armature shunt resistance and armature series resistance therein, a switch for closing the circuit of the motor armature current supply, an additional switch for breaking the armature shunt portion of said circuit, and means for so actuating said switches from the operators starting switch that the armature supply circuit cannot be actuated to close without breaking the said armature shunt circuit.

7. The combination of a motor, conductors carrying current therefor, a lurality of circuits for the armature of sai motor one of which when in use includes means whereby a variable speed condition is imposed upon the motor, electrically actuated switches for selectively opening or closing these said circuits from the operators switch, operating circuits for actuat' said switches, conductors ca current erefor, and an automatica actuated switch constructed and arranged to vary the resistance of the variable speed condition circuit in accordance with current conditions of the armature.

8. The combination of a motor, conduc- 3 tors carrying current therefor, a plurality of circuits for the-armature of said motor onetof which when in use includes means whereby a variable speed condition is imposed upon the motor, electrically actuated switches for selectively opening or closing these said circuits from the operators switch, operating circuits for actuating said switches,

conductors carrying current? therefor, and.

an automatically actuatedswitch constructedand arranged to vary the resistance a of the variable speed condition circuit in accordance with current conditions of the armature, and independently of the armature potential.

9. The combination of a motor, conductors carrying current therefor, a plurality of circuits for the armature of said motor,

one of which contains armature series resistance and armature shunt resistance, electricaliy actuated switches for selectively opening or closing the said circuits from the operators switch, operatin circuits for actuating said switches, con uctors carrying current therefor, andan automatically actuated switch constructed and arranged to vary armature circuit resistance in accordance with current conditions-0f the armature.

10. The combination of a motor, conductors carrying current therefor a plurality of circuits for-the armature 0 said motor, one of which contains armature series resistance and armature shunt resistance, electrically actuated switches for selectively opening or closing the said circuits from the operators switch, operating circuits for actuatin said switches, conductors carrying current ierefor, and an automatically actuated switch constructed and arranged to vary armature circuit resistance in accordance with current conditions of the armature and independently of the armature potential.

11. The combination of a motor, conductors carrying current therefor, an armature circuit for said motor containing armature series resistance and armature shunt resistance, and an automatic eIectro-magnetically actuated switch responsive to the armature current flow only, constructed and arranged ance, and an automatic elcctro-magnetically actuated switch responsive to current flow into the armature, said switch being constructed and arranged to increase the said amount than the aforesaid certain amount above mentioned and when so conversely responding to decrease saidv shuritresistanc'e,

14. The combination of a motor, conductors carrying current therefor, an armature circuit for said motor containing armature series resistance and armature shunt resistance, and an automatic electro-magnetically actuated switch actuated by current flowing outward from the armature, said switch be ing constructed and arranged to decrease the said shunt' resistance when so"responding.

15. The combination of a motor, conductors carrying current therefor, an armature circuit for said motor containing armature series resistance and armature shuntresistance, and an automatic clectro-magnetically actuated switch responsive to a certain amount of current flow outward from the armature and constructed and arranged to decrease the said shunt resistance when so responding; said switch being also conversely responsive to a current flow outward from the armature of less amount than the aforesaid certain amount above mentioned and when so conversely responding to increase the said shunt resistance;

'16. The combination of a motor, conductors carrying current therefor, an armature circuit for said motor containing armature series resistance and armature shunt resistance, and an automatic electro-magnetically actuated switch responsive to current flow into the armature, said switchbeing constructed and arranged to increase the said shunt resistance when so responding and an additional automatic electro magnetically actuated switch responsive to current flow outward from the armature, said switch being constructed and arranged to decrease the said shunt resistance when so responding. 17. The combination of a motor. conductors carrying current therefor, an armature circuit for said motor containin armature series resistance and armature s umt resistance, and an automatic electro-magnetically actuated switch responsive to a certain amount of current flow into the armature and constructed and arranged to increase the said shunt resistance, when so responding; said switch being also conversely responsive to a current flow into the armature of less amount than the aforesaid certain amount above mentioned and when so conversely re sponding to decrease said shunt resistance, and an additional automatic electro-magnetirally actuated switch responsive to a certain amount of current flow outward from the armature and constructed and arranged to decrease the said shunt resistance when so responding; said switch being also conversely responsive to a current flow outward from the armature of less amount than the aforesaid certain amount above mentioned and when so conversely responding to increase the said'shunt resistance. i. '18. In a system of motor control, the combination with the current supply mains thereof of an electro-magnet located in the armature circuit said electro-niagznet being constructed and arranged so as to be polarized correspondingly to the direction of armature current flow, a movable magnet polarized suitably for attraction to the said electro-maguet during armature current flow in a certain dinection-only,-and a switch actuated by thesaid movable magnet for varying the speed con'trollin circuits of said motor control system whi e the current supply mains are transmitting current to the apparatus.

19. In a system of motor control, the combination with the current, supply mains thereof of an electro-magnet located in the armature circuit said electro-magnet being constructed and arranged so as to be larized correspondingly to the direction of armature current flow. a movable magnet polarized suitably for attraction to the said elcctro-magnet during armature current flow in a certain direction and repelled therefrom during armature current flow in the opposite direction, and a switch actuated by the said movable magnet for varying the speed controlling circuits of the motor control system oppositely according to the attraction or repulsion of said movable magnet while the current supply mains are transmitting current to the apparatus.

20. In a system of motor control, the combination with the current supply mains thereof, of an armature magnet, located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondingly to the direction of armature. current flow, and energized correspondingly to the amount of such flow, a movable magnet polarized suitably for attraction to said armature magnet during armature current flow in a certain direction and of a certain amount, and withdrawn therefrom during such directional current flow of less than the aforesaid certain amount, and a switch actuated by said movable magnet for varying the speed controlling circuits of the motor control s-' tem oppositely according to the attraction or withdrawal of said movable magnet, while the current supply mains are transmittin current to the apparatus.

21. n a system of motor control, the com bination of an armature magnet, located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondingly to the direction of armature current flow and energized cor respondingly to the amount of such flow, a series resistance and a shunt resistance in the armature circuit, a movable magnet polarized suitably for attraction to said armature magnet during armature current flow in a certain direction and of a certain amount, and withdrawn therefrom during such directional current flow of less than the aforesaid certain amount and a switch actuated by said movable magnet for varying the resistance in the armature circuit oppositely according to the attraction or withdrawal of said'movable magnet. I

22. In a system of motor control, the combination of an armature magnet, located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondingly to the direction of armaiturecurrent flowand ener 'zed correspondingly to the amount of suc flow, a

series resistance and a shunt resistance in the armature circuit, a movable magnet polarized suitably for attraction to said armature magnetrduring armature current flow in a certain direction and of a certain amount, and withdrawn therefrom during such directional currentflow of less than the aforesaid certain amount and a switch actuated by said movable magnet for varying the aforesaid shunt resistance opposite y according'to the attraction or withdrawal of said movable magnet. g

23. In a system of motor control, the combination bf an armature magnet located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondin ly to the direction of armature current ow and energized correspondingly to the amount of such flow, a series resistance and. a shunt resistance in the armature circuit, a movable magnet polarized suitably for attraction to said armature magnet during current flow into the armature of a certain amount, and withdrawn therefrom during such directional current flow of less than the aforesaid certain amount and a switch actuated by said movable magnet for increasing the said shunt resistance upon the attraction of the movable magnet to the armature magnet and for decreasing the said shunt resistance upon withdrawal of themovable magnet from the armature magnet.

24. In a system of motor control, the combination of an armature magnet located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondingly to the direction of armature current flow and energized correspondingly to the amount of such flow, a series resistance and a shunt resistance in the armature circuit, a movable magnet polarized suitably for attraction to said armatuie magnet during current flow outward from the armature of a certain amount and withdrawn therefrom during such dim. tional current flow of less than the aforesaid certain amount and a switch actuated by said movable magnet for decreasing the said shunt resistance upon the attraction of'the movable magnet to the armature magnet and for increasing the said shunt resistance upon withdrawal of the movable magnet from the-armature magnet. a

25. In a system of motor control, the combination of an armature magnet, located in the armature circuit, said armature magnet being constructed and arranged so as to be polarized correspondingly to the direction of armature current flow and energized correspondingly to the amount of such flow, a series resistance and a shunt resistance in the armature circuit, a movable magnet polarized suitably for attraction to said armature magnet during current flow into the armature of a certain amount, and withdrawif therefrom during such directional current flow of less'than the aforesaid certain amount and a switch actuated by said movable magnet for increasing the said shunt resistance upon the attraction of the movable magnet to the armature magnet and for decreasing the said shunt resistance upon withdrawal of the movable magnet from the armature magnetywith a secondmovable magnet polarized suitably for attraction to said armature magnet during current flowloiitward from the armature o a certain amouiit and withdrawn therefrom during such directional current flow of less than the aforesaid certain amount, and an additional switch actuated by said second movable magnet for decreasin' the said shunt resistance upon the attraction of said second movable magnet to the armature ma et and for increasing the said shunt resistance uponwithdrawal of said second movable magnet from the armature magnet.

26. In a system of motor control, a motor, a speed controlling circuit for said motor,

iao

current supply mains therefor, a regulating.

electro-magnet in the armature circuit provided with a magnetic flux path concentrating its ma etic ines upon an actuation area within sai path, and distributing said magnetic lines substantial] uniformly withln said actuation area, an a polarized actuating member constructed and arranged to move in said actuation area responsively to 1 the'said regulating electro-ma the polarity and degree of magnetization of at and a switch operated by said actuating member for modifying the speed controlling circuit of said motor contro system while the current supply mains are transmitting current to the apparatus.

27. In a system of motor control, a motor, a speed controlling circuit for said motor, current supply mams'therefor, a regulating electro-magnet in the armature circuit consisting of a magnetizin coil, an internal iron core and an externa iron jacket therefor constructed and arranged so as to absorb substantially all the ma 'etic flux arising from the'energization said coil, projections upon said "core and said jacket approaching each other but leaving between them an air-gap so pro rtioned as to concentrate the magnetic ux therewithin and a polarized actuating member constructed an arranged to move in said air-gap responsively to the lari and degree of magnetization of t e sai regulating electro-magnet, and a switch 0 erated by said actuating member for modi ying the speed controlling circuit ofsaid motor control system' while the current supply mains are transmitting current to the apparatus.

28. The combination with an electric motor of reversing switches, interlocking means operated by said reversing switches whereb the closin A of either switch prevents t e closing 0 the other, and electromagnetic means permanently connected to the armature of said motor for retaining said interlocking means operative until the motor is substantially at rest.

29. In a system of motor control the combination with an electric motor of electromagnetic reversing switches therefor, means connected with each one of the reversing switches whereby closing of either switc prevents the electro-magnetic'closlng of the other, and additional electro-ma etic means whereby the said prevention 0 the closin of said other switch continues operative unti the motor speed is substantially reduced irrespective of any opening of either reversing switch.

30. 'In a system of motor control the combination with'anelectric motor of reversing switches therefor, an actuating electro-magnet associated with each switch, an individual operating circuit for each one of said actuating electro-ma ets, a separate switch associated with eaci one of said reversing switches in each of said 0 crating circuits whereby the closing of eit er one of said reversing switches opens the o erating circuit of the other reversing switc and a olding electro-magnet permanently connected to the armature of said motor for retaining such said circuit open until the motor speed is substantially reduced.

31. In a system of motor control the combination with an electric motor of reversing switches therefor, an actuating electro-mag-.

magnet-ic influence of said holding electromagnet. g

32. In a system of motor control the combination with a motor, a current supply therefor, an armature speed circuit for said supply containing armature series resistance and armature shunt resistance therein, an

operators switch for starting said motor control system into operation and controlling its speed circuits, a switch for breaking sui armature shunt resistance path, a switc for connecting the current supply to said armature circuit, and switches for automatically, and gradually cutting out the armature series -resistance of said circuit path upon the connection of the supply .thereto; of means ifor so actuating said switches from the said operators switch that the armature supply circuit cannot be actuated to close without breaking the said armature shunt resistance circuit path.

'33. -In a system of motor control the combination with a motor. a current supply therefor, an armature circuit path containing armature series resistance and armature shunt resistance. therein, an clcctro-magnetic switch which when actuated breaks the armatureshunt resistance path. an electromagnetic switch which when actuated connects the current supply to the armature circuit, automatic switches for gradually cutting out the series resistance from the armature circuit path upon the connection of the supply thereto and the breaking of the armature shunt resistance circuit ath, an operators switch for starting and udjusting said motor, a current supply for said opcrators switch, said switch having a fixed position wherein none of the above mentioned armature current controlling switches arr-actuated, an adjusting position near said fixed position and a starting position more remote therefrom: circuits from said starting position actuating the above mentioned switch for connecting supply current to the armature circuit and said above mentioned switch for breaking the armature shunt resistance circuit, and circuits from said ad usting position for retaining the armature current supply switch in actuated position.

34. In a system of motor control' the combination with a motor, a current supply therefor, an armature circuit path containing armature series resistance and armatureshunt resistance therein, an electro-magnetic switch which when actuated breaks the cutting out the series resistance from the armature circuit path upon the connection of the supply thereto and the bieaking'of the armature shunt resistance circuit ath, an operators switch for starting adjusting said motor, a current supply for said 0 rators switch, said switch having a. fixe position wherein none of the above mentioned armature current controlling switches are actuated, an adjusting position ncargsaid fixed position and 'a' starting position more remote therefrom;' and an additional adjusting position between the aforesaid positions; circuits from said starting position actuating the above mentioned switch for connecting supply current to the armature circuit and said above mentioned switch for breakin the armature shunt resistance circuit, an circuits from said adjusting 3 position for retaining the armature current supply switch in actuated position, and circults from said additional adjusting position for varyin the resistance in the armature circuit an for retaining the armature current supply switch in closed position.

35. In a system of motor control the com.- bination with a motor, a current supply therefor, an armature circuit path contain ing armature series resistance and armature shunt resistance therein, an electro-magnctic switch which when actuated breaks thearmature shunt resistance path, an electromagnetic switch which when actuated connects the current supply to the armature circuit, automatic switches for gradually cutting out theseries resistance from .the armature circuit path upon the connection of the supply thereto, and the breakingof the armature shunt resistance circuit path, an operators switch for starting and adjusting said motor, a current supply for said 0 rators switch, said switch having a fix position wherein none of the above mentioned armature current controlling switches are actuated, an adjusting position near said fixed position and a starting positionmore remote therefrom; circuits from said starting position actuating the above mentioned switch for connecting supply current to the armature circuit and said above mentioned switch for breakin the armature-shunt resistancecircult, an circuits from said. adjusting position for retaining the armature current supply switch in actuated osition, andswitches for varying the resistance in the armature circuit automatically in accordance with armature current conditions.

'36. In a system of motor control the combination with a motor, a current supply therefor, an armature circuit path containing armature series resistance and armature shunt resistance therein, an electro-magnetic switch which when actuated breaks the armature shunt resistance path, an electro magnetic switch which when actuated con--.

nects the currentsupply to the armature circuit, automatic switches for gradually cut ting out the series resistance from the armature circuit path u on the connection of the supply thereto an mature shunt resistance circuit path, an operator's switch for starting and adjusting said motor, a current supply for said oper ators switch, said switch having a fixed position wherein none of the above mentioned armature current controlling switches are actuated, an adjusting position near said fixed position and a startin position more. remote therefrom; and an additional adjusting position between the aforesaid positions; circuits from said starting position actuating the above mentioned switch for connectinglisupfily current to the armature circuit an "a'i above mentioned switch for breaking'tlie' armature shunt resistance circuit, and circuits from said adjusting position for retaining the armature current supply switch in actuated position, and circuits from said additional adjusting position for varying the resistance in the armature circuit and for retaining the armature current supply switch in closed position, and switches for varying the resistance in the armature circuit automatically in accordance the breaking of the ar- 38. In a systemof motor control the combination with a motor, a current supply therefor, a switch for connecting current supply to the armature circuit, an electromagnet for actuating said switch, a circuit for carrying actuating and energizing current supply for said electro-magnet, a switch controlling said actuating and ener zing current supply circuit, means for. c osmg said last mentioned switch, and means for therefor, a switch for connecting current .supply to the armature circuit, an electromagnet for actuating said switch, a circuit for carrying energizing current supply for said electro-magnet, a switch controlling said energizing current supply circuit, means for holding said last mentioned switch closed during the presence of armature potential, and a retarding device for delaying its openin 40. n a system of motor control the combination with a motor, a current supply therefor, a switch for connecting current supply to the armature circuit, an electromagnet for actuating said switch, a circuit for carrying energizing current supply for said electro-magnet, a switch controlling sai energizin current supply circuit, means for closing sai last mentioned switch, means for holding it closed during the resence of armature potential, and a retar ing device for delaying its opening.

41. The combination of a motor, conductors carryin current supply therefor, a circuit for sai motor armature containin armature series resistance, and armature s unt resistance therein, and automatic means constructed and arranged to va said circuit so as to maintain substantia ly the same potential upon the armature under variations in its current conditions.

42. The combination of a motor, conductors carrying current supply therefor, a circuit for said motor armature containin armature series resistance and armature s unt resistance therein, and automatic means constructed and arranged to vary said shunt circuit so as to maintain substantially the same potential upon the armature under variations in itscurrent conditions.

43. The combination of amotor, conductors carrying current supply therefor, a plurality of circuits for sai im sing a different speed condition upon sai motor, means for connecting the motor to either one of said circuits, an armature series resistance and an armature shunt resistance in one of the said circuits, andautomatic means constructed and arranged 'to vary the last mentioned circuit so as to maintain substantially the same potential upon the armature under variations in its current conditions.

44.. The combination of a motor, conductors carrying current supply therefor, a plurality of circuits for said motor each circuit imposing a different speed condition upon said motor, means for connecting the motor each circuit motor to either one of said circuits, an armature series resistance and an armature shunt resistance in one of the said circuits and automatic means constructed and arranged to vary the shunt resistance of said last mentioned circuit so as to maintain substantially the same potential upon the armature under variations of its current conditions.

45. The combination of a motor, conductors carryin current supply therefor, 1!. dr-

cuit for sai motor armature containin armature series resistance, and armature unt resistance therein, and automatic means constructed and arranged to vary said circuit so as to maintain a higher potential upon the armature when it is receiving current from the supply than when it is generating current.

46. The'combination of a motor, conductors carryin current supply therefor, a circuit for sai motor armature containin armature series resistance and armature s unt resistance therein, and automatic means constructed and arranged to vary said shunt circuit so-as to maintain a higher potential upon the armature when it is receiving current from the supply than when it is generatin current.

47. e combination of a motor, conductors carlying current supply therefor, a plurality o circuits for said motor each circuit imposing a difi'erent speed conditionupon said motor, means for connecting the motor to either one of said circuits, an armature series resistance and an armature shunt resistance in one of the said circuits, and automatic means constructed and arranged to vary the last mentioned circuit so as to maintain a higher potential upon the armature when it isreceiving current from the supply than when it is generating'current.

48. The combination of a motor, conductors carrying current su ply therefor, a plurality of circuits for sais motor each circuit im osing a different speed condition upon sai motor, means for connectmg the motor to either one of said circuits, an armature series resistance and an armature shunt resistance in one of the said circuits and automatic means constructed and arranged to vary the shunt resistance of said last men-- tioned circuit so as to maintain a higher potential upon the armature when it is receiving current fromthe supply than when it is generating current.

49. In a system'of motor control the combination of a motor, a current supply therefor, an armature circuit path containing armature series resistance and armature shunt resistance therein, an electro=magnetic switch which when actuated connects the current supply to said armature circuit path, an operator s switch for adjusting and stopping said motor; said operators switch having a fixed sition wherein said electromagnetic switch is deprived of energizing current; thereby depri current sugiply, and" anditional position provided or said operators switch next to the first named fixed position, a supply of current for said operators switch, a circuit from a contact closed by the said operators switch when in said additional position holding the said electro-magnetic switch in actuated position, and automatic means conlthe armature circuit so as to maintain a lngher potential upon the armature when it is receiving current from the supply than when it is generatin current.

50. n a system of motor control the combination of a motor, a current supply-therefor, an armature circuit path containin armature series resistance and armature s unt resistance therein, an electro-magnetic switch which when actuated connects the current supp y to said armature circuit path, an op erators switch for adjusting and stopping said motor; said operators switch having a fixed position wherein said electro-magnetic switch is deprived of energizing current;

thereby de rivin the armature of currentsupply, an an a ditional position provided for said operators switch next to the first named fixed position, a supply of current for said operators switch, a circuit from a contact closed b the said operators switch when in said ad itional position holdin the said electro-magnetic SWll'Lh in actuated position, and automatic means constructed and arranged to decrease the resistance in the shunt portion of the armature circuit as the current received by the armature from the supply decreases and to increase said resistance in the shunt portion of the armature circuit as said re4 eived current increases so as to maintain a higher potential upon the armature when it is receiving current from the supply than when it is generating curre t.

51. In a system of motorcontrol the combination of a motor, .a current supply therefor, an armature circuit path containing armature series resistance and armature shunt resistance therein, an electro-magnetic switch which whenactuated connects the current supply to said armature circuit path, an operator s switch for adjusting and stopping said motor; s a1d o ratprs switch havmg a fixed 'tion w ereln said electromagnetic switch is deprived of energizing current; thereby de the armature of current 8!?)Pl-Y, and an ditional position provided or said operators switch next to the first named fixed position, a supply of current for said operators switch, a circuit from a contact closed by the said operators switch when in said additional posltion the armature of actuated position, and automatic means constructed and arranged to increase the resistance in the shunt portion of the armature circuitas the current generated by the armature decreases and to decrease said resistance as said generated current increases, so as to maintain a higher potential upon the armature when it is receiving current i from the supply than when it is generating current.

52. In a system of motor control the com- ,bmation of a motor, a current supply therefor, an armature circuit path containin armature series resistance and armature s untresistance therein, an electro magnetic switch which when actuated connects the current supply to said armature circuit path, an operator s switch for adjusting and stopping said motor; said operators switch having a fixed position wherein said electro-magnetic swltch is deprived of energizing current; thereby de IlVlIl the armature of current supply, an an a ditional position provided for said operators switch next to the first named fixed position, a supply of current for said operators switch, a circuit from a contact closed b the said operators switch when in said ad itional position holding the said electro-magnetic switch in actuated position and automatic means constructed and arranged to decrease the resistance in the shunt portion of the armature circuit as the current received by the armature from the supply decreases, and to increase said resistance as said received current increases, and to increase the resistance in the shunt portion of the armature circuit as the current generated by the armature decreases and to decrease said resistance as said generated current increases so as to maintain a higher potential upon the armature when it is receiving current from the'supply than when it is generating current.

'53. In a system of motor control the combination of a motor, current supply means therefor, a speed controlling circuit for said motor, a regulating electro-magnet in the armature circuit, and provided with a magnetic flux path concentrating its ma netic lines substantially uniformly within said actuat ion area, and a polarized actuation member movably located within said actuation area, with a retardin device constructed and arranged to de ay the responsive motion of said actuation member to a change of magnetic flux of said regulati electro-magnet, and a switch oper: atedfiiy said actuation member for modifying the speed controlling circuit of said motor control system while the current sulp- 1 6 ply mains are transmitting current to t e apparatus.

54. In a system of motor control the combination of a motor, a speed controlling cirholding the said electro-magnetic switch in cuit for said motor, a regulating electrom magnet in the armature circuit consisting of a magnetizing coil, an internal iron core and an external iron jacket therefor constructed and arranged so as to absorb sub stantially all magnetic flux arising from the energization of said coil, projections upon said core and said jacket approaching each other but leaving between them an air-gap so proportioned as to concentrate the magnetlc fluxtherein, .a polarized actuation member movably located within said airgap, with a retardin device constructed andarranged to delay e responsive motion of said actuation member to a change of magnetic flux ofsaid regulating electro-magnet and a switch 0 erated by said actuation member for modi ing the speed controlling circuit of sai motor control system, while the current supply mains are transmittin current to the apparatus.

55. n a system of motor control the combination with a motor, conductors carrying current supply therefor, a switch for closing the armature current supply, a circuit path for the motor armature which contains armature shunt resistance and armature series resistance therein, anadditional switch for breaking the armature shunt portion of said path and means independent of the armature supply circuit operated by the closure of said first mentioned switch to efi'ect the operation of the said second mentioned switch.

56. In a system of motor control the combination with a motor, conductors carrying current supply therefor, an electro-magnetic switch for closing the armature current supply, a circuit path for the motor armature which contains armature shunt and armature series resistance therein, an additional electro-magnetic switch for breaking the armature shunt portion of said ath, a contact closed by the closure ofsaid first mentioned switch, and a circuit therefrom indeendent of the armature supply circuit ofecting the operation of the said second mentioned switch.

57. The combination with a motor, conductors carrying current supply therefor, an electro-magneticswitch for closing and opening the armature current suppl an electro-magnetically actuated friction rake for the armature, an armature circuit which contains armature series resistance and armature shunt resistance therein, automatic means constructed and arranged to main tain substantially the same potential upon the armature under variations in its current condition,'and means 0 erated by the closure of the said first mentioned switch to release said electro-magnetic friction brake, and to apply said brake .u n its opening.

58. The combinationwith a motor, conductors carrying current supply therefor an electro-magnetic switch for closing and o ning the armature current supply, an e ectro-magnetically actuated friction rake for the armature, an armature circuit which contains armature series resistance and armature shunt resistance therein, automatic means constructed and arranged .to. maintain a higher potential upon the armature when it is receiving current from the supply than when it is generating current, and means operated by the closure of the said -76 first mentioned switch to release, said electro-magnetic friction brake and to apply said brake upon its opening.

59. In a system of motor control, the combination of a motor, conductors carrying current therefor, a circuit for the armature of said motor containing armature series resistance and armature shunt resistance therein, automatic means constructed and arranged to oppositely vary the resistance of said circuit in accordance with increase or decrease of armature current flow and automatic armature connected means operative upon a predeterminedamountof revolution 0 said armature to break the said armature circuit.

60. In a system of motor control the com-. bination of a motor, conductors carrying current therefor, a plurality of circuits for said motor each circuit imposing a different speed condition upon said motor, means for connecting the motor to either one of said circuits, and armature series resistance and an armature shunt resistance in one of said circuits, automatic means constructed and arranged so as to oppositely vary the resistance in said last mentioned circuit in accordance with increase or decrease of armature current fioyv, and automatic armature connected means operative upon a pre- 1 determined amount of revolution of said armature to change the existing circuit connection of the motor to a lower speed circuit connection.

61. In a system of motor control, the combination of a motor, conductors carrying current therefor, a circuit for said motor including means whereby variable speed conditions are imposed thereupon, and automatic means constructed and arranged to oppositely vary said circuit, so as to raiseor lower the potential applied to the armature of said motor in accordance with 'increase or decrease of armature current flow, and automatic means operative upon a redetermined amount of revolution of sai armature, to break the armature circuit.

62. In a system of motor control, the combination of a motor, conductors carrying current therefor, a plurality of circuits for said motor each im osing a different speed condition upon sai motor, means for connecting the motor to either one of said circuits, one of which-includes means whereby variable speed conditions are imposed on the motor, means constructed and arranged to oppositely vary the latter of said circuits so as to raise or lower the potential applied to the armature of said motor automatically in accordance with increase or decrease of armature current flow, and automatic means operative upon a predetermined amount of revolution of said armature to change the existing circuit connection of the motor to in a lower speed circuit connection.

63. In a motor control system a regulator for automatically controlling variations of armature potential whose actuating coil is placed so as to be in series with series armature resistance, and in shunt with shunt armature resistance during current flow into the armature; and in series with shunt armature resistance and in shunt with series armature resistance during current flow outward from the armature.

EDWIN S. MATTHEWS. Witnesses:

AoNns R. MATTHEWS,

Amcm V. Onvnt'r.

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