US411782A - Governor for electro-dynamic machines - Google Patents

Description

(No Model.) 2 SheetsSheet 1* G. F. CARD. GOVERNOR FOR ELEO'TRO DYNAMIC MACHINES.

No. 411,782. Patented Oct. 1, 1889 zl/z'inassasr Z0. .6: firdz'nsfan.

(No Model.) 2 Sheets-Sheet 2.

G. F. CARD. GOVERNOR FOR ELBOTRO DYNAMIC MACHINES.

Patented Oct. 1, 1889.

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UNITED STATES PATENT OEEic.

GEORGE F. CARD, OF COVINGTON, KENTUCKY, ASSIGNOR TO THE GEORGE F. CARD MANUFACTURING COMPANY, OF CINCINNATI, OI'IIO.

GOVERNOR FOR ELECTRO-DYNAMIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 411,782, dated October 1, 1889.

7 Application filed October 29, 1888- Serial No. 289,384. (No model.)

To aZZ whom it may concern.-

Be it known that I, GEORGE F. CARD, a citizen of the United States, residing in Covinge ton, in the county of Kenton and State of Kentucky, have invented a certain new and useful Improvement in Governors for Electro- Dynamic Machines, of which the following is a full, clear, and exact description.

My invention relates to governors for elec- TO tric motors or dynamic machines arranged to automatically maintain a sensible uniform speed of armature rotation under changing loads, current forces, &c., and whose construction is, further, such as to promptly bring the E 5 armature to rest either upon its rotation dropping below a given range of velocities or upon a disableinent of the centrifugal regulator.

My present invention is an improvement on the one shown and described in my pend- 2o ing application filed July 31, 1888, Serial No.

In the accompanying drawings, forming part. of this specification, Figure]. is a top plan view of an electric motor with my govz 5 ernor attached. Fig. 2 is a side elevation of the same. Fig. 3 is a diagram to illustrate the paths respectively taken by the currents.

Supported upon any suitable base A is a field-magnet having several pairs of cores D 1), arranged in any convenient manner, upon which is wound the wire C of a normallyclosed circuit which conveys the driving-cur rent. Beside the said direct-winding fieldcores one pairsay D D, Fig. 3--are Wound 3 5 in the reverse direction, with a comparative low-resistance wire 0, which forms a normally open loop of the direct-winding wire, which,

when closed, shunts part of the current in a direction opposite to the driving current.

This shunt-circuit c is known as the differential circuit. In the normal running condition of the machine this differential circuit is open and currentless and inert, but is capable of being automatically closed either by a speed 5 of the armature in excess of the maximum velocity assigned to it or for which it is gaged, or by the opposite action. of slowing down toward a stop,or also by the disorganization of the centrifugal mechanism of the governor '50 itself. IVhenever from either cause named said differential circuit becomes the path of a current its reversely-directed windings tend to neutralize and, if maintained long enough,

to even overpower the magnetism of the direct windings. The means employed by me for bringing said. differential circuit automatically into action in the presence of either condition mentioned are as follows:

The short-circuit wire or loop diverges at some convenient pointsay F-from the direct-winding wire to two normal]y-stationary terminals or contact-points G II. The contact-- piece G consists, preferably, of a piece of carbon supported by a bracket I and movable in the clamp J. The wire may connect with 6 5 the bracket I at any point, as the insulation at 15 cuts off the current from T or its connections, while the contact-picce H is supported on the bracket II. The other end of the wire 0, forming the loop or shunt circuit, is connected with the bracket I, supporting the shaft L. On the end of this shaft I. is a pulley driven from the armatuieshaft N by the belt N.

O is a centrifugal regulator hinged at one end to the collar 0 and at the other to the hub of the disk P. A spring Rtends to bring the regulator to a collapsed condition. On the shaft L is a non-revolving collar or sleeve S, carrying a bracket S, which extends over So and supports adj ustably the carbon point T.

The terminal or contact point If consists of a bar supported by brackets II, the spring H tending to force it forward, within adjustable limits, into contact with the disk I, which moves backward or forward on and with the shaft Ii, its hub extending through the sleeve S.

The differential circuit is closed by the contact of the carbons G T or the disk I and point H. As the speed of the engine increases beyond the maximum fixed the centrifugal regulator 0 draws the collar S toward it, and with it the bracket S and carbon T. As the carbon T comes in contact 95 with the carbon G the differential circuit is closed, and the reverse current tends to neutralize the drivingcurrent and reduce the speed of the engine, whereupon the centrifugal regulator bccomes more relaxed and Ice the carbon T moves out of contact,opening the difierential circuit. In practice the carbons do not actually part contact and entirely break the differential circuit unless the machine is overloaded; b ut as it beginmtoslow d QtheJinpMeI carbons is lessened, producing a variable rEistance'by the changesofpi'essuie." A still greatefcliange of-resistaneeisproduced by the slight parting of the carbons, producing a short are, so that within a very short space or limit of motion We have a variable resistance ranging from a pressing contact of the carbons to the actual or complete breaking of the circuit, thus securing very great delicacy of the regulator. The action of these parts is so delicate and prompt that the engine can be kept running at its maximum speed with great constancy and without any possibility of running away.

If the engine begins to slow down too much, the regulator 0 becomes more collapsed and the spring R forces the disk P into contact with the contact-point H, when the differential circuit is again closed and the driving-current neutralized and the engine entirely stopped. In case of any derangement of the centrifugal regulator from any cause the same action takes place, stopping the engine. In my application filed July 31, 1888, the general principles of my governor are shown. The arrangement, however, is less simple and efiective. A single contact-point connected with the negative rheophore of the differential circuit vibrates between the two contact-points of the positive. In my present construction Ihave two pairs of contact-points. Where either contact-point is in motion the friction causes sparks, and is apt to cause irregular wearing of the surfaces and make the action less certain. I find, also, the pair of carbon points arranged to move to or from one another without rotation or other movement much more delicate and accurate and less danger of producing irregular and uneven contactsurfaces, as wellas securing the variable resistanoe due to changes of pressure peculiar to carbon.

For adjusting the limit of speed I provide the gage U, which consists of a finger or pointer adjustable longitudinally in a slot by the thumb-screw U. The carbon T is adjusted in the clamp S, so that it will come into contact with the point G when the disk P comes under the pointer or gage U. Should the carbons wear or burn away, so as to permit the disk P passing the pointer, they must be readjusted to keep the speed within the limit, which is done by means of the screw X,

machine or motor, of the driving-circuit, the

normally-open low-resistance difierential circuit having two pairs of rheophores at its terminals, one of each pair of rheophores being movable and the other relatively stationary, the centrifugal speed-regulator, and connections between the same and the movable rheophores, whereby the respective pairs of rheophores will be caused to contact with variable degrees of pressure and thereby vary the resistance of the differential circuit when the speed of the dynamo becomes abnormal, substantially as described.

2. The combination, in an electro-dynamic machine or motor, of the driving-circuit, the normally-open differential circuit having the carbon rheophores at its terminals, one of which is movable, and the centrifugal speedgovernor connected to the movable carbon rheophore, and thereby adapted to vary the resistance of the differential circuit at abnormal speeds, substantially as described.

3. In an el'ectro dynamic machine or motor, the combination of the armature, the centrifugal specd-governor revoluble synchronously therewith, the field-magnets having the differential circuit wound in the reverse direction to the drive-circuit, said difierential circuit having the vibrating terminal connected to and operated by the governor, and the opposing relatively stationary terminals on opposite sides of the vibrating terminal, substantially as described.

4. In an eleotro-dynamic machine or motor, the combination of the centrifugal speed-go"- ernor, the field-magnets having the differential circuit wound in the reverse direction to the drive-circuit, said differential circuit having the vibrating terminal operated by the governor, and the opposing terminals on opposite sides thereof, and the gage to limit the play of the vibrating terminal, substantially as described.

GEORGE F. CARD.

Witnesses:

ALFRED M. ALLEN, GEORGE HEIDMAN.

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