Nov. 26, 1946. ’ E. E. MOYER ' 2,411,145 ELECTRIC CONTROL CIRCUIT Original Filed Oct. 29, 1941 lg$5 .-kELSE #1 \N. 0 Ew Inventor Elmo E; Meyer, )3}; His Attorne‘g. 1] 2,411,745 Patented Nov. 26, 1946 UNITED srA'rEs PATENT‘ OFFlCE ELECTRIC CGNTROL CIRCUIT Elmo E. Moyer, Scotia, N. Y., assignor to General Electric Company, a corporation oi‘ New York - Original application October 29, 194i, Serial No. 416.3%. Divided and this appiicaticn February 25, 1343, Serial No. d'i'l,il3l ' ll My invention relates to electric control circuits -. ticulariy to improved electric con“ trol circuits for accomplishing variable energiza tlon oi‘ a load circuit, such as an electric motor, by the use of electric valve translating apparatus“ This application is a division of my application sér, No. 416,974.», filed October 29, 1941, entitled It is an object of my invention to provide a new and improved electric control circuit. It is another object of my invention to provide a new and improved electric control circuit for an electric valve translating apparatus for efiect= ing variable energization of a load circuit which provides for a predetermined initial energizatlon of the load. ' Electric control circuit, and assigned to the same It is still another object of my invention to assignee as the present invention. In control systems employing electric valve 10 provide a new and improved electric control sys tem I employing self-synchronous type motion translating apparatus for e?ecting variable ener transmitting devices which insures smooth regu gization of a load circuit and particularly in sys lating action under all operating conditions. terns where the load circuit comprises a motor Briefly stated, in the illustrated embodiment of which is to be maintained in some de?nite opera my invention I provide a controlled electric valve tive relation with respect to another motor, it is system for variably energizing the armature desirable to insure that the output of the electric winding of an electric motor to maintain a pre valve apparatus is returned to a predetermined determined speed relatlon between the motor and value each time the system is deenergized so that another motor which is not energized through the initial energization of the load circuit is always the same. In systems of this character employed 20 the electric valve means. ‘The control of the electric valve means to effect the desired variable for controlling the energization of one of a plu energlzation is accomplished by means of motion rality of motors to maintain the motors in de?nite transmitting devices including a differential mo speed relation by means of synchronous motion tion transmitting device which is operatively con transmitting devices driven by the motors and operating to control the position of a movable 25 nected with the rotor of a phase shifting device for controlling the excitation of the electric valve element for varying the output of the electric means. The connection between the rotor of the valve means, it has been found that if the mov differential signal device and the rotor of the able element is positively driven in accordance phase shifting device is accomplished by means with ‘the relative positions of the movable ele ments of the motion transmitting devices, uneven. 30 of a torque clutch which permits synchronous movement of the differential device after the operation of the regulating system results if the rotor of the phase shifting device has reached speed relation of the motors continues to depart the limit of its movement. This provides for from the desired relation after the movableele-s smooth functioning of the control at the time the ment of the valve controlling means has reached the limit of its movement. In order to overcome 35 desired speed relation is again attained and oper ating of the movable element of the phase shift“ this dimculty I provide a connection between the ing device within its effective range is resumed. motion transmitting devices and the movable ele In order to insure that the initial output of the ment of the tube controlling means which permits ' electric valve apparatus is always the same upon the motion transmitting devices to remain in syn chronism after the movable element of the con 40 energization of the anode-cathode circuit thereof, 1 provide means for automatically returning the trol device has reached the limit of its travel. In rotor of thc phase'shiiting device to a predeter this way a continued temporary departure of the mined position upon deenergization of the anode desired relation between the movable elements cathode circuit of the electric valve means and and the motors after the movable element of the _ also provide means for preventing energization tube controlling means has reached the limit of of the anode-cathode circuit until the rotor has its travel permits the motion transmitting devices been returned to the predetermined position. In to remain in synchronlsm and as soon as the speed order to improve the smoothness of action of the relation approaches that desired and the. motion control system still further I provide an improved ' transmitting devices tend to rotate the movable element of the controlling means in the opposite 50 anti-hunting circuit including a resistor-capacitor combination responsive to voltages of the load direction the control‘ is picked up smoothly as circuit for modifying the excitation voltages ap» contrasted with the sudden changes which occur if the motion transmitting devices temporarily plied to the electric valves. rthe anti-hunting circuit includes a pair'of parallel resistors each lose synchronism with the rotating elements of of which is provided with a variable tap for vary“ the motors which are controlled. 2,411,745 ing the magnitude thereof so-that it is possible to adjust independently the time constant ofthe condenser circuit and the magnitude of the re sistance included in the control circuit. My invention will be better understood by ref erence to the following description taken in con nection with the accompanying drawing and its _ scope will be pointed out in the appended claims In the drawing, the single ?gure is a schematic representation of one embodiment of my inven tion. ‘ - Referring now to the drawing, I have shown my invention embodied in a controlled electric valve system for variably energ’zing the armature with the voltages of the phase terminals of the threeephase stator winding 35 of a phase shift ing device 36 having a three-phase rotor winding 31. The phase shifting device 38 is of a'type well known in the art and is similar in mechanical construction to a three-phase wound rotor in duction motor. The circuit between the three phase terminals of the stator winding 35 and the respective control members 25 of valves I g, 20 and 2| is completed through current limiting re sistors 38. Thev'neutral terminal of the stator winding '35 is connected to the cathode bus 36 of the valves I9, 28 and 2! through a portion of a resistor 39 determined by the positionof the windings of a direct current motor 90 to maintain 15 slider 40. Resistor 39 and a parallel connected a predetermined speed relation between the mo resistor 4| form part of an anti-hunting circuit tor Ill and another direct current motor i I which which is operative to introduce by means of the has the armature l2 thereof energized from a di 7 portion of resistor 39 included in the circuit of rect current supply 13 through a suitable motor the control members 25 a voltage dependent upon starting and control circuit (not shown). The 20 changes in voltage across ‘the terminals of ar direct current ‘motor ID has the terminals of the mature id of the machine it. The anti-hunting armature Id thereof connected in the direct cur circuit includes a resistor 62 and capacitor 63 rent circuit of an electric valve recti?er illus connected in series across the terminals of the trated generally by numeral H5. The motors l0 armature It and a capacitor lit connected be and ii each include a ?eld winding l5 energized 25 tween the common point of resistor 52 and yea from a suitable source of direct current I1 pacitor t3 and the terminal of parallel resistors through a variable resistance It. 39 and Eli remote from the cathode bus 34!. The As mentioned above the armature winding of. condenser M for a given voltage of the armature I the motor to is energized from the direct current it is charged to a predetermined value. Changes circuit of an electric valve recti?er it. As illus 30 in the armature voltage result in a change in the trated in the drawing the recti?er is a three charge of the capacitor M and the charging cur ' phase half-wave system comprising three electric rent ?owing through resistor 39 introduces a di valves I9, 20 and 2i each preferably of the type rect current bias voltage in the circuit of vcontrol comprising a container enclosing an ionizabie me members 25 which a?ects the conductivity of the dium,_ such as a gas or vapor, and ‘within which 85 valves in a direction to oppose the change in ar are mounted an anode 22, a cathode 23 and asso mature voltage. The magnitude of the bias volt ciated heater element 213, a control member or age for a given current ?ow through resistor 39 grid 25 and a shield grid 26. The particular type is controlled by the position of the slider all while of valve illustrated~ is not essential to the present the position of a short circuiting slider 85 on re invention and any of the well known types of 4.0 sistor 4| determines the total resistance of the controlled electric valves may be employed, if de parallel resistance combination 39 and Ill to de sired. The anodeecathode circuits of the electric valves are energized from a three-phase alternat ‘ termine the time constant of the discharge cir-i cult of the anti-hunting capacitor it. Capaci ing current supply circuit 2? which energizes an tor 43 cooperating with resistor 42 operates as alternating current bus 28 under the control of a 45 ?lter to remove a portion of the ripple from the manual switch '29. The anodes of the electric voltage of the anti-hunting circuit. Capacitors valves I 9, 20 and 2! are connected to the end ter £511 are connected between the respectivecontrol minals of a Y-connected secondary winding 3d members 26 of electric valves 19, 2D and 2i and of an anode transformer 3i having a delta-con the cathode bus 34 and serve to minimize tran nected primary winding 32 connected to the al 50 sient voltages on the control members and im ternating current bus 28. The direct current cir prove the controlling action thereof. cuit of the recti?er is completed from the neu As previously mentioned, the motor i0 is vari tral connection 33 of the secondary winding 30 ably energized to operate at a speed dependent upon the speed of the motor [I i. The arrange to one armature terminal of motor Ill and from the other armature terminal of the motor to the 55 merit for controlling the position of the rotor 37! cathode bus 34 of the electric valves i9, 20 and of phase shifting device 36 to accomplish this 26. As is well understood by those skilled in the speed relation between motors in and M will now art the three-phase recti?er circuit described be described. A source of alternating current above is effective to supply direct current to the control voltage is derived from the alternating armature of the motor In at a voltage dependent dd current bus 28 by means of a control transformer upon the energization of the control members or 66 having a primary network it? comprising three grids 25 of the electric valves. phase windings provided with taps which may _ The control circuit for energizing the control - members 25 to e?ect Variable energization of the be adjusted to provide the desired magnitude of control voltage. The secondary network 48 pro motor in will now be described. In the arrange 65 vides a source of energizing voltage for the rotor ment illustrated the motor to is intended to op Winding 31 of the phase shifting device 3%. The erate at a ?xed ‘speed relation with respect to the transformer is also provided with secondary motor H as may be desired in many commercial windings t9 and 5d. Winding 69 provides a applications such. for example, as in the case of source of energy for heating the cathode heaters a cable making equipment where motor Hi, for 241 of electric valves 89, 20 and El and the sec example, may be the reel driving motor and the ondary d6 provides a source of voltage for en motor it may be the ?yer motor or, in other ergizing the rotor windings 5i and 5'2 of angular words, the motor which controls the twist or motion transmitting devices 53 and 56 respec ‘lay of the cable. The conductivities of the elec tively. The devices 53 and 553 are provided with tric valves lQ-Zl are controlled in accordance 75 three phase Y-connected stator windings 55 and 9,411,745 5 a as respectively with the phase terminals of stator winding 55 connected with the phase terminals valves I9, 20 and 2| are controlled by the movable contacts 66 of an anode contactor 61 having an of the three phase rotor winding 5.‘! of a differen operating electromagnet 68 including an operat tial motion transmitting device‘ 58 while phase ing coil 69. The coil 68 is connected to be en ergized from one phase of the transformer sec ondary network ‘8 through a manually controlled switch 10 and a pair of spaced’fixed contacts ‘H terminals of the winding 56 are connected with l ,the phase terminals of the polyphase stator winding 59 of the differential motion transmit- , the stator terminals of the differential device and - which are bridged by‘a conducting member 12 when the phase shifting device is in the position are of such a rating that they take a. leading of minimum output of the electric valves. The tingdevice 58. Capacitors 60 are connecte'dacross cooperating contacts ‘H and 12 also provide a excitation current equal to the lagging excitation mechanical 'stop for the rotor of the phase shift current required by the differential device with ing circuit. A mechanical stop 13 is provided the result that the exciting current which must to limit the movement of the rotor winding 37 be supplied to the differential by the device 53 for example, is equal only to the power compo 15 in the opposite direction. It is apparent that these stops may be adjusted in angular position nent of the current which is in general only to determine the minimum and maximum output a small portion of the total excitation current. of the electric valve means. A variable contact As illustrated in the drawing, the rotor wind 14 actuated by the relay 68 completes a circuit ing SI of device 53 is coupled to the shaft of motor ill by means of suitable gearing designated by 20 in parallel with the contacts ‘H to provide a hold ing circuit for the coil 68 after it has moved .the the numeral 6!, and the rotor 52 of device 5| is mechanically coupled to the shaft of motor I I by suitable gearing. 62. This gearing is arranged so 7 contacts 65 to closed position. ’ The rotor 31 of the phase shifting device 38 has that the speed of rotation of windings ii and 52 are equal when the desired speed relation be tween the motor ill and the motor It exists. As is well understood the Selsyn system including an inherent tendency to rotate in a direction to devices 53, 5B and 58 operate to produce a torque mum output when the anode-cathode circuits of electric valves are deenergized, I provide means on the rotor 5? dependent on the displacement reduce the output of the electric valves i9, 20 and ii. In order to utilize this tendency to restore the phase shifting device to the position of mini between windings 5i and 52. For example, if 30 for loading electrically the stator winding with impedance elements such as resistors 15 in re windings 5i and 52 are in equilibrium position sponse to opening movement of the contacts 66. ' no torque is produced on winding 51. However, As illustrated in the drawing, this is accomplished a change in speed of one of the motors from the by means of a switching device ‘it having mov desired speed with respect to the other motor causes a relative displacement of the windings 5i 33 able contacts Tl for connecting one of the re and 52 and torque is produced on winding 5i sistance elements 15 in circuit between each pair of terminals of ‘the stator winding 35 of the de-. dependent on the magnitude and direction of the vice 36. "The device 76 is provided with an actu relative displacement of the windings 5i and 52. ating coil ll'a connected to be energized from one As illustrated in the drawing, the rotor winding 57 is mechanically coupled by means of a shaft 40 phase of the control power supply transformer secondary 45 through a circuit including a mov 63 to a torque clutch illustrated schematically at able contact 18 on the anode contactor 61. From 64 which has the output shaft 65 thereof con an inspection of the circuit of coil 11 it is seen nected with the rotor of the phase shifting selsyn that it is electrically connected with the trans 36. The torque coupling provides what under normal operation is a positive drive of the rotor 45 former secondary winding 48 whenever the anode contacts 88 are closed. in this way the resistors of the phase shifting device 36 but which per ‘15 are automatically disconnected from the stator mits continued rotation of the differential Selsyn winding of the phase shifting device 36 when the after the phase shifting rotor has reached the anode leads of the electric valves i9, 20 and 2| limit of- its travel. This arrangement allows the differential Selysn to continue to rotate in the 60 are closed by closure of contacts 66. When the rotor 31 of the device 86 is energized from the differential selsyn to continue to rotate in the supply circuit 28 this loading of the stator in event that the departure from the desired speed creases the torque tending to rotate the phase relationship between machines Ill and H is not shifting device to the position or minimum out? immediately corrected by control of the electric valves I9 to 2| before the winding 31 reaches one 55 put of the electric valves and to maintain the same in that position with the cooperating con of its extreme positions. tacts ‘H and “I2 operating as a mechanical stop With the motor control system illustrated it is . against which the rotor is held. desired that the electric valves 19, 20 and 2| Although the operatic/n of the various elements have their anode-cathode circuits energized and that the control circuit therefor be adjusted so 60 of the system described above has been described during the description, it is believed that the fea that the output voltage is insu?icientto rotate tures and advantages of the present invention will the reel motor l0 until after the motor ‘I! has been started. Preferably the minimum output‘ be more apparent from a brief consideration of the operation of the system as a whole. Let it be of the valves is su'?lcient to produce considerable torque in the reel but insu?icient to rotate it. To 65 assumed that switches 29 and '16 are open and that both motors lo and il are-at standstill. If this end means are provided for insuring that the rotor 3101’ the phase shifting device 36 is re it is desired to start the system, switch 28 is ?rst turned to the position of minimum output of the closed energizing transformer 46 and the rotor winding of phase shifting device 36. The Selsyns electric valves when the anode-cathode circuits of the electric valves are deenergized and for pre 70 53 and 54 are also energized and the cathode heater elements of the electric valves l9, 2G and venting the energization of the anode-cathode 21 are energized. The contacts ‘H are normally circuits until the rotor has been returned to the position corresponding to minimum output volt closed and resistors 15 are thereby connected age of the electric valve recti?er. Referring across the terminals of the stator windings 35 of again to the drawing, the anode circuit of the 75 the phase shifting device 38, thus increasing the acreage torque produced on the rotor to insure that it is rotated to the position of minimum output and that movable conact‘ I2 is closed on contact Ii. After the cathode heater elements are at oper ating temperature, preferably insured by a time delay relay (not shown) having a contact in cir dependent upon the voltage of motor it. Any change in this voltage produces a change in the condenser charge at a rate dependent upon the time constant of the condenser resistor circuit. The resistor 39 is. connected in the circuit of the control members 25 so that the polarity of the cuit with switch 7@, the switch ‘ill is closed and voltage caused by a change in the condenser coil 69 of relay 6% is energized from one phase charge is in a direction to'oppose the change in of winding 458 through the contacts ll and'l2- of voltage of the armature machine i0 causing the the limit switch associated with the phase shift 10 change in the condenser charge. In this way ing device 36. As soon as relay 68 picks up, con overshooting of the system is prevented and a tact 18 is- closed to complete a circuit for coil smooth regulating action obtained. The slider 65 ‘Ha to operate contacts ill to open circuit position controls the magnitude of resistance in circuit and disconnect one terminal of each of the re- I with condenser Lid and in this way controls the sistors ‘l5 from the stator winding 35. The con time constant of the condenser circuit. The tacts 66 in the anode leads are closed and the slider d0 controls the portion of resistor- 39 in contact ‘M in parallel with contacts ‘H and I2 is the control circuit and in this way controls the magnitude of the anti-hunting voltage for a given closed to complete a holding" circuit for the coil 69. The tube circuit is now in operating condi current through resistance element 39. Con tion and will function to impress a variable volt 20 denser d3 cooperates with resistor (32 to provide a age on the armature winding of motor to de ?lter to remove some of the ripple from the anti pendent upon the relative position of windings 5i hunting voltage. The tendency of the regulat and 52 of the devices 53 and 56 respectively. The ing system to hunt may also be decreased by the next step in the operation is the starting of the introduction of-reduction gearing between the motor i! which is brought up to operating speed rotor 57 and rotor 31’ of the phase shifting device. The gearing may be incorporated in the clutch by any suitable starting circuit (not shown). As unit 6d if desired. motor it starts to rotate winding 52 will move with respect to winding 5! and in this way pro When it is desired to shut down the motors, motor H is ?rst deenergized and brought to a duce a torque on winding 57] which is transmitted to rotate the movable element of phase shifting 30 standstill by dynamic braking if desired and with the control circuit for motor iii functioning device 36 in a direction to increase the output in this way the motor ill follows motor it to voltage of the electric valve recti?er and in this standstill at which time switch W is opened. 1 way cause the reel motor iii to- start rotating. Upon opening of the control switch Ill coil 89 of The torque imparted to the winding 51 and its the anode contactor operating relay 68 is opened associated structure is always in a direction to to deenergize the anode-cathode circuits of the rotate the movable element 31 in a direction to ‘effect the change in the ‘impressed voltage on electric valves i9, 20 and 2i. Contact 18 is also opened to deenergize the winding Ila of the relay the armature of motor Iii necessary to change its It thus allowing contact II to close and connect speed in the proper manner to bring the ele ments ‘5i and 52 into the correspondence and in resistors 75 across the stator winding 35 of the phase shifting device 36. As described above this this way to maintain the desired speed relation between motors l8 and H. ' insures that the winding 37 is returned to the position of minimum output against the stops ‘ Inasmuch as movement of the rotor 37 of the provided by contacts ‘H and 72 and places the phase shifting device 36 to one of its extreme system in position to be again. operated. If the positions may fail temporarily to restore the de shutdown is for a long period the contact 29 may sired positional relation between the. movable be opened and the system completely deenergized. elements of motors H3 and H, it is desirable to provide for relative movement between the wind While I have described what I at present con ing El of the differential motion transmitting de-T sider the preferred embodiment of my invention, it will be obvious to. those skilled in the art that vice 58 and the rotor 37. To this end the torque clutch 6d interposed between the winding 57 and various changes and modi?cations may be made the winding 37 permits relative movement of without departing from my invention, and I. these windings when the torque required to ro therefore, aim» in the appended claims to cover all such changes and modi?cations as fall within tate winding GI exceeds a certain value. The the true spirit and scope of my invention. clutch is adjusted so that the windings 37 and 57 are maintained in fixed relation to each other What I claim as new and desire to secure by as long as winding 37 is not against the stops Letters Patent of the United States is: provided by contacts ‘H and 72 at one limit of 1. In combination, a supply circuit, a load cir travel and the mechanical stop ‘l3 at- the other cuit, electric translating apparatus interconnect limit of travel. In this way the system includ 60 ing said circuits including electric valve means ing motion transmitting devices 53, 5d and 58 are having a control member for controlling the con allowed to remain in synchronous relation so that r, as the elements of the motors ill and I I approach ductivity thereof, phase shifting means including the desired relationship and the phase shifting control member to thereby variably energize said a movable element for variably energizing said device 3‘? is to be moved away from its extreme 65 load circuit, means for stopping said movable ele ment at a predetermined limit of travel, means position the devices 53, 5d and 58 are functioning smoothly and the winding ill is not operated 11n evenly as it would tend to if it were resynchro forimparting a driving force to said movable element ,dependent upon the energization of said load circuit, and a mechanical connection be ni’zing after having been out of step with the remainder of the motion transmitting system. 70 tween said last mentioned means and the mov In order to prevent hunting of the regulating able element of said phase shifting means nor system the circuit including resistor d2, capaci mally providing a positive driving connection tor M and parallel resistors 39 and d! are con therebetween but permitting said last mentioned nected across the armature terminals of the m0 means to continue movement in the same direc tor ill. The capacitor tilt tends to have a charge 75 tion required to move said movable element to ' 2,411,745 10 said limit of travel after the movable element of. ' cal connection normally providing a positive said phase shifting device has been stopped at drive but permitting relative movement between the movable element of said .phase shifting the limit of its travel‘ 2. A supply circuit, a dynamo-electric machine, electric translating. apparatus interconnecting means and the movable element of said motion transmitting system when thegnovable element said circuit and said machine including electric of said phase shifting means reaches a limit of valve means having acontrol electrode, phase. its travel. ‘ _ shifting means including a movable element for 4. A supply circuit; a dynamo-electric machine, controlling the conductivity of said electric valve electric translating apparatus interconnecting means, a self-synchronous motion transmitting 10 said circuit and said machine including electric system for producing a torque dependent upon valve means having a control electrode, a control the operation of said dynamo-electric machine, circuit for controlling the energization of said and a torque clutch interposed between a mov control electrode including a phase shifting de able element of said motion transmitting system vice having a rotatable element, means for posi and the movable element of said phase shifting 15 tioning said movable element in accordance With device to permit said movable element of said the operation of the dynamo-electric machine motion transmitting system to remain in syn comprising a self-synchronous motion transmitchronism after the movable element of said phase ting system including a differential motion trans shifting device reaches the limit-of its travel. mitting device having a movable element, me~ 3. A supply circuit, a dynamo-electric machine, 20 chanical means interconnecting the movable ele electric translating apparatus interconnecting ment of said motion transmitting system and the said circuit and said machine including electric rotatable element of said phase- shifting device valve means havinga control electrode, phase comprising‘ means for normally driving the ro shifting means for controlling the conductivity tatable element of said phase shifting device in of said electric valve means including a movable 25 fixed relation to the movable element of said element movable between predetermined limits to motion transmitting system, said last mentioned vary the conductivity of said electric valve means means providing for relative movement of said between a maximum and a minimum, a self rotatable member and said movable member synchronous motion transmitting system for pro when the torque required to rotate said rotatable ducing a torque dependent upon the operation of 30 element exceeds a predetermined ‘value to permit said dynamo-electric machine, mechanical means the movable element of said motion transmitting interconnecting the movable element of said mo system to remain in synchronism. tion transmitting system and the movable ele ment of said phase shifting means, said mechani ELMO E. MOYER. '