US1711672A - Remote control system - Google Patents

Description

y 1929- L. E. COON 1,711,672

REMOTE CONTROL SYSTEM Filed July 27, 1925 2 yMmMAf/y Patented May 7, 1929.

UNITED STATES PATENT OFFICE.

LESLIE E. .OOON, OF CHATHAM, NEW JERSEY, ASSIGNOR TO WESTERN ELEGTBTG COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

REMOTE CONTROL SYSTEM.

Application filed July 27, 1925. Serial No. 46,274.

This invention relates to remote control systems and its object is to provide a system whereby the operator at a central station may exercise very close control of apparatus at a distant station.

In remote control systems now in use, a device such as a power switch at a substation can be operated from the dispatchers station by inaugurating a series of events which involves the operation of a number of relays, selectors, etc., and to return such a device to its original condition a similar series has to be gone through. Such systems are adapted primarily to change the position of a power switch from closed to open position or vice versa and permit no intermediate variations in the operation. These systems are not well adapted to remote control systems in which the control to be exercised is very close as, for example, in hydro-electric power plants where the flow of water through turbines requires close adjustment or in some stations where the load carried by a generator is to be varied.

The present invention provides a remote control comparable to that which could be exercised by an attendant directly operating the device to be controlled.

In the present embodiment of this invention, each of the generators has associated with it a pair of devices to raise or lower the load, and also a pair of selectors. The selectors are stepped around under control of a transmitter at the central or dispatchers station until one of the selectors is one step short of selecting the associated device in which position it is held when the impulses stop, the other selectors restoring in the well known way. A key is then operated by the dispatcher to give the held selector another step in which position its arm closes a circuit to operate a relay which starts the device, which may be a motor, to operate means to change the generator output to the desired extent whereupon release of the key stops. the motor due to the selector moving back one step.

This invention will be better understood from the following description in connection form of the invention; Fig. 2 represents a portion of the stepping selector in one position while Fig. 3 represents the same portion of the selector in another position.

Referring to Fig. 1, A represents a central station located at a point distant from a remote station B. At the remote station are two devices 1 and 2 the action of which is to be controlled from station A.

The drawing represents a system for load control which may be accomplished by changing the field resistance of generators. The system is not limited to use in such connection but its application to a power system wherein the field resistance of generators is varied has been illustrated to simplify its description.

Devices 1 and 2 are represented as motors, 1 being referred to as a raise load device while 2 is referred to as a lower load device. These devices are arranged to vary the resistance 31 of generator 32 by meanaof cooperatlng gears 33 and 34, threaded shaft 35. actuating sliding contacts 36 and 37 in an obvious manner.

At station. A are two transmitter keys 3 t and 4 adapted to control respectively devices 1 and 2. The transmitter keys are in a local circuit arranged to operate relay 5 which is of the pole changer type adapted to impress on line wires 6 and 7 impulses of alternate polarity from a current source 8. At station B these impulses are impressed on selectors such as 9, to operate them to within one step of closing a circuit, the closing of which circuit operates a relay such as 10 to start device 1 or 2. The apparatus associated with device 1 is designated generally by 30 while rectangle 11 represents another selector, relay, con'denser etc, associated with device 2. The selectors illustrated are of the type disclosed in Patent No. 1,343,256 to J. 0. Field, dated June 15, 1920. It is understood that the system is not limited to such selectors but any selector ofa similar type may be used.

A key 12 at station A gives the final pulse to step the arm 13 of selector 9 at station E the one step required to contact with the contact 14c. As explained in the above mentioned patent, if contact of key 12 is broken at statlon A, the selector arm will not return to its normal position but will drop back but one step so that if the key 12 is again operated arm 13 again contacts with contact 14 to cause relay 10 to operate which again operates motor device 1. x

This action will be more clearly understood by referring to Figs. 2 and 3. In Fig. 2 the selector mechanism is shown in the position it assumes at the cessation of the last pulse caused by the transmitter. Armature 38 is in the neutral or unoperated position, contact arm 13 carried by wheel 39 is within one step of making contact with contact 14. Wheel 39 is held in this position by means of piece 40 attached to wheel 39 which is engaged by holdinig arm 41. It is to be understood of course that transmitter 4 sends a different number of impulses than transmitter 3. In other words a given number of impulses which step selector 9 around to the point where it will be held by the member 40 will not cause the selector 11 to be held since at that moment'the member 40 ofselector 11 is not opposite the holding arm 41 of selector 11. When the next pulse is sent through the selector windings (caused by operating key 12 Fig. 1) armature 38 takes up a position such as that shown in Fig. 3. Arm 42 attached to armature 38 is provided with two pins 43 and 44. In the position shown in Fig. 3 pin 43 has moved arm 45, thereby causing pawl 46 attached to arm 45 toengage one of the teeth 47 on wheel 39 which moves the wheel one step to make contactbes tween arm 13 and contact point 14. This same action would have been caused if armature 38 had beenattracted by the core of the other winding. In this case pin 44 would have caused the movement of arm 45. Upon the cessation of the pulse (when contact at key 12 is broken Fig. 1) the armature resumes its neutral position and the associated mechanism returns to the position shown in Fig. 2. 1

The operation of the system is as follows: Assume that it is desired to raise the load. Transmitter key 3 marked Raise Fig. 1 is caused to rotate. As soon as the transmitter cam moves, contact is made between it and contact arm 15 which closes a circuit from battery 16, conductor 17, contact arm 15, cam

of transmitter 3, conductor 18 winding of relay 19, conductor 20 to battery 16. Relay 19 is therefore energized and in operating pulls up both armatures. At its left armature it closes an obvious circuit to operate relay 21 which removes the chargingisource from battery 8 to provide against any surges etc., which might be impressed on the line from the-chargmg source. At its right armature relay- 19 closes an obvious circuit through relay 22 to-operate it and hence connect battery 8 through contacts and armatures of relay 5 to the transmission line.

-As the transmitter key continues to rotate contact is made and broken between arms 15 and 23 to alternately energize and deenergize relay 5 over a circuit from battery 16, conductor 17, contact arms 15, 23, conductor 24, winding of relay 5, conductor 20 to battery 16. Relay 5 being of the pole changer type, upon energizing and deenergizing impresses impulses of alternate polarity on selector 9 at station B from current source, or battery, 8. This circuit may be traced from battery 8, front or back contact and left armature of relay 5, left armature and front contact of relay 22, line wire 6, conductor 25, windings of selector 9, condenser 26, conductor 27, line wire 7 right armature and either front or back contact of relay 5 to battery 8. The code transmitted by key 3 steps selector arm 13 around to within one step of engagement with contact 14. The transmitter cam then completes its rotation and returns to its initial position in which position contact arm 15 is out of engagement with thecam and also with arm 23 and hence relay 19 becomes deenergized. Relays 21 and 22 are also deenergiz'ed, relay 21 again connecting charging source to battery 8 and relay 22 disconnecting .the transmission apparatus from the line.

If key 12 at station A is now operated it will have the same effect as the first step in the operation of transmitter key 3 namely, relay 19 will be operated which in turn will operate relays 21 and 22 as described above and for the same reason. However, key 12 has no control over relay 5 and hence current flows over line Wires 6 and 7 in but one direction. This pulse controlled by key 12 steps selector arm 13 into engagement with contact 14 and closes a circuit from battery 28 through relay 10 over an obviouscircuit. At

its left armature relay 10 closes a shunt circuit around condenser 26 which will have become charged by the continuous flowing current. If this shunt circuit were not provided currentlwould cease to flow when condenser 26 became charged and selector arm 13 would drop back from contact 14.

At its left armature relay 1O closes an obvious circuit from current source 29 to cause the operation of raise road device 1.

If key 12 is now caused to break its circuit relay 22 will open the circuit through. the selector windings and thereby permit selector arm 13 to drop back one step breaking the energizing circuit for relay 10 which upon deenergization opens the circuit for raise load device 1. If required, key 12 may again be operated to cause the operation of device 1.

With the necessary indicators at station A the load at station B may be re ulated within very close limits by means of key 12. After the load-has been properly regulated the selector arm is returned to its initial position by again operating the "transmitter key 3. Since now the selector arm is not in its initial position it will not be at a stopping point when the transmitter key has ceased transmitting and the arm will therefore return to its initial position.

The code which transmitter key 4 is adapt-- ed to transmit will actuate the selector controlling the -lower load device 2 represented as contained in 11. The other operations are identical with those just described in connection with the raise load device.

This system may be modified in various ways to accomplish this purpose and the above description and drawing refer to but one embodiment of the invention which is limited only by the scope of the following claims.

What is claimed is:

1. In combination, a central station, a remote station, devices to be regulated, electromagnetic means for controlling said devices, selectors and operating means therefor, a circuit including said selector operating means, each selector operating means, having a condenser in series therewith, means at the central station for impresisng a code of impulses of alternate polarity on said circuit to'cause one of said selectors to select one of said elec tromagnetic means, muiti-contact relays at said remote station, one for each selector operated thereby to short-circuit the associated condenser at one of its contacts in the selecting position, a circuit closed at a second contact of said relay and including the associated electromagnetic means, and means including a key at the central station for controlling said selector to hold said circuit closed.

2. A remote control system comprising a central station and a remote station, line conductors joining said stations, devices at said remote station motors thereat for regulating same, impulse transmitters at said central station, selectors at said remote station responsive to codes of impulses sent out by said impulse transmitters to be actuated within one step of selecting the corresponding motor, a key at said central station, a circuit controlled by said key for giving the impulse required to move said selector another step and thereby to select said motor, and means tending normally to restore the selector, said selector having means to hold it one step from the selecting position when said circuit is opened by said key.

3. A remote control system comprising a central station and a remote station, line conductors joining said stations, a generator at the remote station to be regulated, means including a pair ofmotors at said remote station for raising and lowering the load on. said generator respectively, a relay for each motor for controlling the same, step-by-step selector switches at said remote station each having means adapted to operate one of said relays when in its operated position, means including transmitter keys at the central station adapted to actuatesaid selector switches to within one step of selecting the corresponding motor to start the same, means including a key at said central station adapted when operated to step the selector switch one step to select said motor, and means tending normally to restore the selector switch, said switch having means to hold the selector switch one step from the operated position upon release of the key.

4. In a control system, a line circuit, a controlled device comprising an actuating coil supplied through said line circuit, a condenser in the circuit of said coil, a source of direct current, means for holding said device in a predetermined position after it has been moved to said position by said actuating coil, means adapted to effect the connection of said source to said line circuit so that the proper series of impulses are produced through said actuating coil to eflect the movement of said device to said predetermined position, means for connecting said line circuit to said source to effect movement of said device from said predeterminedposition to another position, and means for completing a short-circuit around said condenser when said device is in said last mentioned position.

5. i In a control system, a line circuit, a controlled device comprising an actuating coil connected to said line circuit, a. condenser in the circuit of said coil, a source of direct current, means for holding said device in a predetermined position after it has been moved to said position by said actuating coil, means adapted to effect the connection of said source to said line circuit so that the proper series of impulses are produced through said actuating coil to efiect the movement of said device to said predetermined position, means for connecting said line circuit to said source to effect movement of said device from said predetermined position to another position, a control relay, a circuit for said control relay, contacts in said control relay circuit arranged to be closed when said device is in said last mentioned position, and a circuit around said condenser arranged to be completed in rezlsponse to the energization of said control re ay.

In witness whereof, I hereunto subscribe my name this 25th day of July, A. D. 1925.

LESLIE E. COON.

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