US1305044A - System of control - Google Patents

Description

C. C. WHITTAKER.

SYSTEM OF CONTROL.

APPLICATION man APR.5. 1917.

Patented May 27, 1919.

4`SHEETS-SHEET l.

INVENTOR Char/@66. Mii/faken ATTORNEY C. C. WHITTAKER.

SYSTEM 0F CONTROL APPLICATION FILED Ams. 1911.

1,305,044. Patented May 27,1919.

4 SHEETS-HEBT 2.

INVENTOR I ATTORNEY C. C. WHITTAKEH.

SYSTEM OF CONTROL. APPLICATION FILED Ams. 1917.

1,305,044. Patented May27,1919.

4 SHEE`I S-SHEET 3.

Accelera/'on Jem/ence of d'wfcea.

Jer/'es Trans/Tian Pera//c/ Para//e/ Trans/'fion C. c. WHITTAKER.

SYSTEM 0F CONTROL. y

Patented May 27, 1919.

4 SHEETS-SHEET 4.

APPLICATION FILED APR. 5.19I7

Grou

Ground INVENTOR wnNEssEs; l

Y l j A'ToRNEY UNITED STATES PATENT' oEEIcE.

CHARLES C. WH ITTA KER, OF WILKINSBUBG, PENNSYLVANIA, ASSIGNOR T0 WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A` CORPORATION 0F PENNSYLVANIA.

SYSTEM or coN'rnoL.

Patented May 27, 1919.

Application led April 5, 1917. Serial No. 159,935.

To all whom it may concern:

Be it known that I, CHARLES C. WHIT- TAKER, a citizen of the United States, and a resident of Wilkinsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Systems of Control, of which the following is a specification.

My invention relates to systems of control and especially to the regenerative control of electric vehicle motors, and the like, under predetermined conditions.

One object of my invention is to provide a system of the above-indicated character, wherein the regenerated current is automatically maintained between predetermined limits under certain braking conditions of the momentum-driven machine.

More specifically stated, it is the object of my invention to provide an automatic regenerative control system embodying a limit switch, or the like, that is adapted to lift to normally maintain the regenerated current aboveaa redetermined lower value -and a second re ay device or limit switch that is adjusted to lift at a predetermined higher value only under free-runnin conditions of the momentum-driven mac ines, that is, when the machines are connected in either full-parallel or full-series relation.

A further object of my present invention is to provide means, operated by the abovementioned high-current relay device, to complete certain emergency or alarm circuits only under conditions of the weakest excitation of the momentum-driven machines, that is, only when the maximum amount of resistance is included in the machine circuits.

My invention may best be understood by reference to the accompanying drawings, wherein Figure 1 is a diagrammatic view of the main circuits of a system of control embodying my invention; Fig. 2 is a diagrammatic view of the auxiliary governing circuits for manipulating the various circuitswitches that are illustrated in Fig. 1; Fig.

.3 and Fig. 4 are sequence charts of wellknown form for indicating the desired order of operation of the various switches during the accelerating and the regenerating periods, respectively; Fig. 5 is a detailed diagrammatic view of one of the complete maincircuit switches that are shown in Fig. 1; and Fig. 6 and Fig. 7 are simplified views of the accelerating and the regenerating circuit connections, respectively.

Referring to Fig. 1, the system shown comprises a plurality of suitable supply-` circuit conductors respectively marked Trolswitches RRl, RR2, RRS and R 4; a t ird main-circuit resistor JR that is adapted to be short-circuited by a switch J3; a plurality of motor-controlling switches LS, J l, M1, and Gl; alimit switch L of a familiar type; a high-current relay 1 for a novel purpose to be described; a change-over switch CO, preferably of the drum type and electrically controlled, as explained in connection with Fig. 2, for arranging certain of the mainmotor, and also the auxiliary, circuits during both the accelerating and regenerating periods in accordance with its occupation of the positions marked Acc. and Reg; a fieldcircuit controlling device PK of the drum type, having an operatin mechanism OM, for varying the active va ue of a plurality of resistors FRl and FR2 that are disposed in circuit with the main field windings during the regenerating period, as set forth later; a motor-generator or dynamotor D of a familiar type for supplying exciting energy to the main field-winding circuits during the regenerating period; and a relay decoil thereof is connected from the high motor or an equivalent motor-generator set may be employed, if desired, and the customaryfunctions of such a machine, for example, driving air-compressors. and furnishing energy for various auxiliary circults, may be utilized, if deemed advisable.

The relay device RD is preferably o f a familiar solenoid type, and the actuating voltage terminal of the switch M1 to the lower-voltage terminal of the armature. A2. It will be observed that, when the parallelconnecting switches M1 and G1 are closed,

` the relay device receives the voltage of each of the parallel-related armatures, while, upon the closure of the series-connecting -switch J 1 and the opening of the parallelconnecting switches, the relay device is energized in accordance with the combined. voltages of the two sets of armatures, for regenerative purposes to be set forth.

The control device PK comprises a main drum portion MD that is provided with suitable stationary and movable contact members for gradually short-circuiting the liield circuit resistors FRl and F R2 as the mechanism OM as described in connection with Fig. 2, whereby a step-by-step movement of the PK controller is effected.

The operating mechanism OM is of a familiar type and comprises a pinion .6 ythat is rigidly secured to the end of the shaft 5 of the PK controller and meshes with a horizontally movable rack me1nber'7, with the ends of which a plurality of .pistons 8 and 9 are respectively associated. A plurality of suitable operating cylinders 10 and 11 are provided for the pistons 8 and 9, and a plurality of valve members 12 and 13 are adapted to admit iiuid pressure from any suitable source (not shown) through pipes or passages 14 and 15, respectively, in accordance with predetermined conditions t0 be described. The valve 12 is normally closed to .exclude fluid-pressure from the cylinder 10 and to permit communication of the cylinder with the atmosphere. An actuating coil 0n is provided for controlling the action of the valve 12. On the other hand, the valve 13 is normally open to admit Huid-pressure to the cylinder 11, whereby the operating mechanism is biased to the position shown, and an actuating coil Off is taneously energized, whereupon the initialunbalanced fluid-pressure conditions are reversed toactuate the pistons toward the right. l If it is desired to arrest the controller movement at any point, the oli' coil is deenergized, and balanced-pressure conditions obtain in the two cylinders, thus positively and lreliably stopping the controller.- To effect return movement, it is merely neces'- sary to denergize both coils, whereby the initial unbalanced-pressure conditions are restored and the pistons are moved to the illustrated positions.

The high-current relay device or limit switch 1 is adjusted to lift at some predetermined current value higher than the average or normal value, for example, 20% higher than the setting of the limit switch L. In general, the high-current relay 1 is arranged to ei'ect a backward movement of the' controller PK, that is, to produce a 90 decrease the regenerated current whenever the relay lifts, as hereinafter more fully set forth. The relay device 1 is provided with a bridging contact disk 2 which closes certain circuit connections for the operating mechanlsm OM normally andcompletes an emergency or alarm circuit when the relay occupies its upper position,l as is subsequently` described in detail.

However, the arrangement of auxiliary circuits is such that the limit switch 1 becomes operative only in certain'positions of the controller PK, which preferably correspond to the weakest lexcitation of the momentumdriven machines during both parallel and series machine operation, thatis, to the inclusion of the greatest possible value of resistance in the machine circuits.

The auxiliary governing system that is shown in Fig. 2 comprises, in addition to the 110 actuating coils of the various switching devices that are illustrated in Fig. 1, a plurality ,of interlocking contact members of a l familiar type that are illustrated in Fig. 5y in connection with the switch LS1, and the interlocking4 ID, a master controller MC that is adapted to occupy a plurality. of. operative positions a to n, when operated in one direction that corresponds to acceleration of the motors, and a plurality of operating positions a to c, when Vmoved in the opposite direction that corresponds to 'regeneration of the momentum-driven machines; a master reverser MR of a familiar type; a suitable source of energy, such as a battery B, for energizing the various actuating coils through the master controller MC and through a plurality of train-line conductors TL, whereby' mult-iple-unit. op-

eration of my system may be readily effected, as will be understood; a control relay CR, for a purpose to be described; and certain auxiliary contact members of the change-over switch CO, the limit switch L, the high-current relay 1; the relay device RD, which closes certain auxiliary circuits in a manner to be set forth; and a Huidpressure-controlling valve V that is electrically governed as hereinafter described.

The fluid-pressure-controlling valve V may be of any familiar type and is shown as comprising essentially an actuating coil 16 A for governing a normally closed valve member 17 to efect the admission of fluid pressure through an inlet 18 from any suitable source (not shown) to an outlet or working passage 19.

The valve V is energized only under emergency conditions, namely, the lifting of the high-current relay 1, and may be employed for the purpose of venting the brake-pipe to apply the brakes or to blow an alarm whistle, for instance, whereby the mechanical braking system may be thereby rendered operative or the 'train operator may be warned of the high-current conditions in the system and may manually operate the system to eliminate such conditions.

Assuming that yit is -desired to effect acceleration of the main motors, the master controller MC may be actuated to itsinitial accelerating position a., provided that the master reverser MR and the main reversingswitch RS occupy their forward positions,

as illustrated, whereupon, one circuit is established from the positive terminal of the battery B through conductor 20, train-line conductor 21, conductor 22, control fingers 23 and 24, which are bridged by contact segment 25 of the master controller in its position a, conductor 26, contact member 27, conductor 28 and contact member 29 of the master reverser MR in its forward position, conductor 30, train-line conductor 31, conductor 32, contact member 33 of the main reversing switch RS in its forward position, conductors 34, 35 and 36, the actuating coil of the switch LS1 and an interlock (lO-Acc., whence circuit is completed through conductors 37, 38 and 39, Contact member 40 of the change-over switch CO in its position Acc., conductor 41, train-line conductor 42, conductor 43, control fingers 44 and 45, which are bridged by contact segment 46 of the master controller, conductor 47, train-line conductor 48 and conductor 49 to the negative terminal of the battery B. The switch LS1 is thus closed, as indicated in the sequence chart of Fig. 3.

A further circuit is established, at this time, from the contact segment 25 of the master controller through conductor 58, contact segment 59, conductor 60, contact segment 61 and control linger 62 of the various sections of the master controller; conductor 63, train-line conductor 63a, conductor 64, contact member 65 of the change-over switch CO in its osition Acc., conductor 66, interlocks RR -out and RR2-out, conductor 67, the actuatin coil of the switch J1, conductor 68 and t e interlock LS1- in to the negative conductor 39. Upon the closure of the switch J1, a holding circuit therefor is formed by interlock J1-m, which directly connects conductors 66 and 67.

Still another circuit is established in position a of the master controller from contact segment 25 through control finger 69, conductor 70, train-line conductor 71, conductor 72, interlocks J 1-in and G1--out, conductors 73 and 74, the parallel-connected actuating coils of the switch R1 and RR1, conductor 75 and interlock LS1-in to the negative conductor 39.

Referring temporarily to the main circuits that are shown in Fig. 1, the closure of the various switches that have been mentioned completes a main circuit from the trolley through conductor 76, the switch LS1, conductors 77 and 78, conductor 80, the armature A1, conductor 81, contact member 82 of the change-over switch CO in its position Acc., conductor 83 and certain contact members of the reversing-switch RS, field winding F1, reversing switch RS, conductor'84, contact member 85 of the change-over switch CO, conductor 86, switch R1, conductor 89, the entire resistor ARl, conductor 90, switch J 1, resistor JR, conductor 91, the entire resistor AR2, conductor 92, switch RR1, conductor 93, armature A2, conductor 96, the actuatin coils of the high-current relay 1 and of t e limit switch L, conductor 97, reversing switch RS, conductor 98, field-winding F3, conductor 99, reversing-switch RS, conductor 100, contact member 104of the change-over switch CO in its position Acc., and conductor 105 to the negative sup lycircuit conductor Ground. (See Fig. 6

Referring again to Fig. 2, when themaster controller MG is actuated to its second accelerating positionb, a circuit is established from the positively energized contact segment 61, through control finger 106, conductor 107, train-line conductor 108, conductors 109 and 110, interlock J1-in, conductor 111, the actuating coil of the switch J3, interlock 112-J3-out, conductor 113, interlock M1-out, interlock LS1-in, conductor 115, contact member CO--Acc. and conductors 37 and 38 to the negative conduc-tor 39. As soon as the switch J3 is closed, an additional holding circuit therefor is completed from the actuating coil thereof through interlock 112-J3-in and conductors 116 and 116a to conductor 39, which additional circuit is employed in connection with certain other resistor-shortcircuiting switches, as about to be described.

In position c of the master controller, the

117, whence circuit is completed through conductor 118, train-line conductor 119, conductors 120 and 121, the actuating coil of Vso the switch R2, conductor 122, interlock 123-, R2-out, conductor 124, interlock 125-J3- in, and thence through conductor 113, as

previously described. Upon the closure ofthe switch R2, a holding circuit therefor is completed from conductor 122, through interlock 123-R2--in, and conductors 126 and 127, to the conductor 116.

In position d of the master controller, -a circuit is completed from the contact segment 25 through control finger 128, conductor 129, train-line conductor 130, conductors 131 and 132, the actuating coil of the switch RR2, conductor 133, and thence through interlock 123-R2-in, as already set forth.

In position e, a circuit is completed from the contact segment 25 through control nger 134, conductor 135, train-line conductor 136, conductors 137 and 138, the actuating coil of the switch R3, conductors 139 and 140, interlock 141-R2-in, and thence through conductor 124, as previously described.

In position f, a further circuit is completed `from the contact segment 25 through control linger 142, 'conductor 143, train-line conductor 144, conductors 145 and 146, the actuating coil of the switch RR3, conductor 147 and interlock 148-R3-in, a common holding circuit for the switches R3 and RR3 being completed from the interlock 148 through conductor 127 to the conductor 116.

In position g, a circuit is established from the contact segment 61 of the master controller through control finger 149, conductor 150, train-line conductor 151, conductor 152, contact member 153 of the change-over switch CO in its position Acc., conductors 154, 155 and 156, the actuating coils of the switch R4 and RR4, conductor 157 and interlock LS-in to the negative conductor 39.

In position g, the initial energizing circuit of the actuating coils of the switches R1 and RR1 is also opened after the closure of the switches R4 and RR4, by reason of the disengagement of the control finger. 69 from vthe contact segment 25. Such action, however', does not vary the main-circuit resistance since direct shunting paths around the main-circuit resistors ARl and AR2 are provided through the switches R4 and RR4, respectively. An open-main circuit at this time is prevented by the use of a holding circuit including conductors 35, 163, 208 and 209, interlocks R4out and RR1-in and conductor 74 which is connected to the R1 and RR1 switch-actuating coils, thus preventing the opening of switches R1 and RR1 until the closure of switches R4 and RR4,-

In position h, the switches R2, RR2, R3

and RR3 are opened by reason of the disengagement of the contact segment 25 from the corresponding control lingers. To effect initial parallel connection of the motors, the master controller may be moved toward its position i, whereupon, at first, the contact segment 61 engages 4control nger 166, whence circuit is completed through conductor 167, train-line conductor 168, conductor l169, contact member 170 of the change-over switch CO in its position Acc., conductor 171, interlocks Rl-out and RR2-out, conductor 172, the parallel-related actuating coils of the switches M1 and G1, conductor 173, and interlock LS1-in to the negative conductor 39.

Immediately after the closure of the switches just mentioned, the contact segment 61.015 the master controller becomes disengaged from the control fingers 62 and 106, thereby de'ner'gizing the previously described circuits of the actuating coilsy of the switches J 1 and J3, respectively. However, the opening of the switch J 1 before the closure of the switches M1 and G1 prevented by an interlocking arrangement similar to that set forth in connection with the switches R4 and RR4, namely, comprising conductors 165, 174 and 17 5, interlock Ml--out and interlock J 2-in, which is connected directly to the acuating coils of the switch J 1. rl`hus, the energization of the J1 actuating coil is maintained through the holding circuit just recited until the switch M1 closes to 'interrupt the connection between conductor 175 and interlock J2-in.

' Referring, for the time'being, to Fig. 1, the main circuits that are established in the initial parallel connections of the motors that correspond to position z' of the master controller may be set forth as follows: from the trolley through the main armature A1, main field winding F1, switch R4, and the resistor ARl, as previously described, conductor 182, switch G1, contact member 183 of the change-over switch CO in its position Acc., conductor 184 and conductor 103 to the negative supply-circuit conductor Ground, as already traced. The circuit of the-other motor is completed from the 'trolley through conductors 76, 77 and 185, switch M1, the resistor AR2, conductor 186, switch RR4,

conductor 93 and then through the other the armature A2.

In position i (Fig. 2), the contact segment 2 5 re'ngages control finger 117, whence .circuit is established as previously recited through the actuating coil of the switch R2, thence through the interlock 123-R2-out, conductors 124 and 177, interlocks M2-in and LS1-in and thence through conductor 115 to the negative battery terminal, as pre- In the final position n, the contact segment 61 of the master controller engages control finger 178, whence circuit is completed through conductor 179, train-line con-u ductor 180, conductor 181, interlock Gl-in and conductors 73 and 74 to the actuating coils of the switches R1 and RR1, in accordance with a circuit already traced. Although the resistor-short-circuiting switches are manipulated during the parallel operation of the motors in a diierent sequence from that employed during the series acceleration of the motors, it will be observed that the change of sequence is necessary by reason of the altered relations of the main circuit resistors with respect to the motors, and, in either case,- the manipulation of the switches is such as to gradually eect acceleration of the motors.

More specifically stated, the switches R1 and RRl are initially employed, whereby the current traverses the corresponding resistors in a certain direction duringl series acceleration; whereas the switches 4 and RR4 are employed during the first portion of parallel acceleration, and the current traverses the main resistors in the opposite d1- rection. However by connecting the intermediate switches, R2 and R3, for example, from intermediate points of the resistor AR1 to the terminal of the switch R1 that isremote from the armature A2, the same sequence of operation of the intermediate switches may beemployed during both series and parallel operation, which 1s desirable for manufacturing and commercial reasons.

Assuming that the vehicle is coasting at a relatively high speed and that it is desired to eiect regenerative operation of the system, the master controller MC may be actuated to its initial regenerative position a', whereupon a circuit is iirst established from the positive terminal of the battery B through conductor 20, train-line conductor 21, conductor 200, interlocks LS1- out and PK-a, the actuating coil Reg. of the change-over switch CO, contact member 201 over the change-over switch in its position Acc., conductor 202, train-line conductor 203, conductor 204, control fingers 205 and 45, which are bridged by contact segment 206 of the master controller in its position a and thence,through conductor 47,to the negative battery terminal, as already described in connection with the motor acceleration. The change-over switch is thus actuated to its regenerative position Reg., in a wellknown manner.

The switch LS1 is not closed at this time by reason of the exclusion of the contact member CO-Acc. from the ener 'zing circuits of its actuating coil. The c osure of the switch LS1 is entirely dependent upon the upward actuation of the relay device RD, which takes place, under certain regenerative conditions, in a manner to be described. v

A further circuit is established from the conductor 34 through conductors 163, 208,

209 and 210, control ngers 211 and 212,

which are bridged by contact segment 213- of the interloc drum ID, conductor 214, contact member 215 of the change-over switch CO in its position Reg. and conductor 154 to the actuating 'coils of the switches R4 and RR4, as hereinbefore described.

A circuit is established Vsimultaneously from the contact segment 213 of the interlock drum ID through control finger 216, conductor 217, contact member 218 of the change-over switch and thence through conductor 171 to the actuating coils ofthe switches M1 and G1, as already traced.

In the meantime, the ield windings of the main machines are excited by the generator armature G in accordance with circuits about to be traced, and the voltage of the main momentum-driven armatures is thus built up to a point where the combined effect of the machine speed andield excitation suice to produce a voltage across each of the two armatures A1 and A2, or, in other words, impresses a voltage upon the actuating coil of the relay device RD, that is preferably higher than the supply-circuit voltage by a predetermined amount, whereupon, the relay device is actuated to its upper position to complete the circuit of the actuating coil of the switch LS1 from the conductor 36 through the actuating coil, conductor 225, auxiliary contact members 226 of the relay device RD in its upper or closed position, and conductor 227 to the negatively-connected conductor 37. Upon the closure of the switch LS1, .a holding circuit therefor is formed from conductor 225, through conductor 228, interlock LS1-in, and conductor 229 to conductor 227, whereby the auxiliary contact members of the relay device RD are bridged, and the device is inoperative with respect to varying the circuit connections during the remainder of the regenerative operation.

Upon the closure of the switch LS1 and the actuation of the relay 1, the previouslymentioned interlock LS1- in completes the circuits of the actuating coils of the switches RR2, R2, R3 and RR3, which are respec- Aer;

tively connected through conductors 220, 221 and 222 to suitable control fingers that are joined by a contact member 223--00- Reg., to which energy is supplied from the conductor 154 through interlock J 1--out and M2-in and conductor 224. In this case, however, the conductor 115 is opened-circuited at the change-over switch, and circuit is completed from interlock LS1- in through contact members 114 of lthe limit switch L, and conductor 116a to the negative conductor 39. i

Since an appreciable interval of time, approximately one and one-half second s in a typical case, is necessary for the'full initial field-winding current from the auxilia generating armature G to build up, a su cient regenerated or armature current will have been established to lift the limit switch L, and the remainder of the normal automatic regenerative operation is governed by the limit switch, in accordance with customary practice.

The progressive closure of the resistorshort-circuiting switches thus'occurs a short time after the closure of the switch LS1 and the attainment of a predetermined' fieldwinding current, to short-circuit the main resistors AR1 and AR2, dependent upon the main armature current. Thus a steady initial regenerated current of a normal value and producing a suitable retarding effort is automatically obtained.

Referring temporarily to the main circuits that are shown in Fig. 1, the connections that are established by the actuation of the .change -over switch CO and the closure of the connecting switches just recited may be set forth as follows: One circuit is completed from the lower-voltage terminal of the armature A1,'through conductor 81, contact member 187 of the change-over switch CO in its osition Reg., conductor 86, switch' R1,

con uctors 89 and 182, switch G1, contact member 188 of the change-over switch, conductor 189, field-regulating resistor FR1 and conductors 190 and 191 to the negative supply-circuit conductor Ground. A similar circuit for the other motor is completed from the lower-voltage terminal of the armature A2 through conductor 96, the actuating coils of the high-current relay 1 and of the limitvswitch L, conductors 97 and 192, contact member 193 of the change-over switch, conductor 194, field-regulating resistor FB2 and conductor 95 to the negative supply-circuit conductor Ground. The two ,motor armatures are thus respectively connected 4in series relation with the regulating resistors FR1 and FB2 across the supply circuit. (See Fig. 7.)

A further main circuit is established from the contact member 188 of the change-over switch through conductor 196a, contact change-over switch, conductors l84`and 103,

contact member 104a of the change-over switch in its position Reg., conductor 199, the exciting armature G and conductor 199@ to the conductor 190. A similar circuit for the other ficld Winding is completed from the conductor 97 through conductor 98 the field Winding'F2, the actuating coil of the field-winding current relay 1, conductor 100 and thence to conductor 103 and the exciting armature G as just described. The exciting armature G is thus connected to excite the main field .windings through the resistors F R1 and FRZ, respectively. However, such arrangement of main-circuit connections forms no material part of my present invention, but is fully shown and described in a co-pending application of R. E. Hellmund, Serial No. 44,443, filed August 9, 1915, and assigned to the Westinghouse Electric & Manufacturin Company.

As previous y stated, the limit switch L governs the normal automatic operation of the system, in accordance with a' familiar practice, that is, the master controllerV M-C may beplaced in its position e or c cor-v responding to the free-running conditions,

of the machines, that is, full-parallel and full-series connection, respectively, and the main controller PK will then operate stepby-step, in accordance with the position of the limit switch L, which lifts whenever the current exceeds a' predetermined lower value and thus automatlcally' maintains the regenerated current above such predetermined value.

0n the other hand, the high-current relay 1 is lifted to its upper position only when the regenerated current attains a relatively high value which it is desired shall not be exceeded, to interrupt the common energizin circuit for the actuating coils On and O of the controller PK and, therefore, produce a backward movement of the co-ntroller and a corresponding reduction of regenerated current, in accordance with principles already pointed out.

However, such action of the high-current relay lis effected only under the above mentioned free-running conditions of the momentum-driven machines, since the cooperating contact members of the relay 1, in its lower position, are short-circuited or bridged `in all positions of the master controller MC except positions e -and la', corresponding to full parallel and fullseries Vconnection of the machines, respectively.

The bridging circuit just mentioned is completed from one of the lower stationary contact members of the relay device 1 through conductor 310, train-line conductor 311, conductor 312, control ngers 313 and 314 which are bridged by either contact segment 315 of the master controller in positions a to d', inclusive, or by contact segment 316 in positions f' to j', inclusive, conductor 317, train-line conductor 318 and conductor 319 to the other stationary lower contact member of the high-current relay 1.

It will be understood that, if automatic operation under the control of the low-current limit switch L is not desired, manual step-by-step operation of the controller PK, in accordance with the movements of the master controller MC, may be effected, and such manual operation is subsequently described in detail.

Whenever the high-current relay device 1 occupies its upper or emergency position to eii'ect the backward movement of the controller PK, an additional circuit is completed thereby, provided the controller is moved backwardly-as far as either its initial parallel position a or initial series position f. Under such conditions, the additional circuit in question is established from the positively energized conductor 163 through conductor .325, the coperating stationary and movable contact members 2 of the highcurrent relay 1 in its upper position, conductor 326, control fingers 327 and 328 which are bridged by contact segment 329 of the controller PK in its position a or by contact segment 330 in position f. conductor 331, actuating coil 16 of the valve V, and conductor 332 to the negative conductor 39.

Thus, the valve V is energized to apply the air-brakes or blow an alarm whistle, as previous described, whenever the high-current relay 1 occupies its upper position and the controller PK occupies its initial parallel or initial series position concurrently, that is, when the maximum resistance is included in the machine circuits and, conse-- quently, the weakest field excitation of the main machines obtains.

A further auxiliary circuit is then established from the conductor 208 through conductor 230, interlocks BB3-in, Gl-in and CO-Reg. and conductors 231 and 74 through the actuating coils of the switches R1 and RRl, as previously set forth.

When the master controller is moved to its second regenerative position b a circuit is completed from the contact segment 232, which is connected by conductor 231a to the segment 61 of the master controller, through control finger 233, conductor 234, train-line conductor 235, conductor 236, where the circuit divides, one branch including conductor 237, control finger 238, contact segment 239 and control finger 240 of the interlocked drum ID, conductors 241 and 242, the actuating coil On, contact members 2 of the high-current relay 1 in its lower position, and conductor 243l to the negative conductor 39, and the other branch including conductor 244, control fingers 245 and 246, which are bridged by contactsegment 247, conductor 248, interlock G1-in, the actuating coil Off, interlock R3in, conductor 249, auxiliary contact members 250 of the limit switch L and contact members 2 of the rela 1 in their lower or operative positions, an thence, through conductor 243, to the negative conductor 39. Inasmuch as the two actuating coils On and Off of the PK controller are simultaneously energized, forward movement of the controller toits position b occurs inl accordance with the principles already set forth.

In position b of the interlock drum, the circuit of the actuating coil On is maintained by the engagement of the control finger 238 with the contact segment 239, while the control finger 245 becomes disengaged from the contact segment 247, thereby denergizing the actuating coil Off and, consequently, effecting the previouslydescribed balanced-pressure conditions in the operating mechanism OM to positively and reliably stop the PK controller in position b.

In position c of the master controller, the contact segment 232 engages control finger 166, whence circuit is completed through conductor 187, train-line conductor 168, conductor 169, contact segment 251 of the change-over switch, conductor 251a and control finger 252 which is connected to contact segment 247 of the interlock drum ID in position b thereof. The two actuating coils On and Off are thus again simultaneously energized and the PK controller is actuated to its position c, whereupon the control finger 252 is disconnected from the contact segment 247 while the contact segment 239 engages another control finger that corresponds to control finger 252 and thus maintains the energization of the on actuating coil.

.In position d, contact segment 232 engages control finger 149,- whence circuit is completed through conductor 150, train-line conductor 151, conductor 152, contact member 253 of 4the change-over switch, conductor 253e and control finger 254, which engages contact segment 247 of the interlock drum in position c and thus permits movement of the drum in the manner already described as far as position d;

In position e of the master controller, a control finger 255 engages the contact segment 232, whence circuit is completed through conductor 256, train-line conductor 257, conductor 258, contact member 259 of the change-over switch CO, conductor 260 and control finger 261, which engages the contact segment 247 of theV interlock drum in position d and thus permits movement of the drum to position e, which correment of the controller PK. It will be un- 1 derstood that, when the limit switch is utilized, the master controller may be initially actuated to its osltions c or 7c', and the controller PK will then advance from notch to notch in accordance with the action of the limit switch L, as is familiar practice.

If the master controller MC is moved toward its initial series position f', a circuit is first established from the contact segment 232 through control finger 267, conductor 268, train-line conductor 269, conductors 270 and 271 and control finger 272 which engages the Contact segment 239 of the interlock drum and consequently, maintains the energization of the actuating coil On durin the transitional movement of the contro ler PK. A new circuit for similarly maintaining the energization of the off' coil circuit comprises control finger 296 which engages contact segment 232, conductor 297, train-line conductor 298, conductor 299, and control finger 300 which makes contact with segment 247 until just before position f of the interlock drum ID, is reached.

The control fingers 263 and 264 are also bridged by contact segment 273 between the positions e and f of the controller PK,

' thus bridging the stationary contact members of the limit switch L and servin to maintain the actuating coil Ofi' energize to insure the movement of the controller PK to its initial series position fl.

As soon as the controller PK passes beyond its position e the contact segment 213 engages control finger 274.-, whence circuit is completed through conductor 275, contact vmember 276 of the change-over switch CO, where the circuit divides, one

branch including conductor 66, interlocks RRl-in and RR2-out, since the contact segment 232 disengages the `corresponding control fingers of the master controller during the movement thereof t0 position ff', and thence through conductor 67 to the actuating coil of the switch J 1, as previously set forth, and the other branch including conductor 260, interlock Gl-out as soon as the switch G1 has opened, as about to be set forth, interlock Jl-in and conductor 27 8a to the contact member 223CO-Reg.,'

thereby effecting the progressive `closure of switches RR2, R2, R3 and RRS. I

The switch J3 is also closed at this time by reason of the completion of a circuit from the interlock 223-CO-Reg. through conductors. 219, 110, interlock J l-in and conductor 111, whence circuit is completed in accordance with circuits already traced. In addition, a circuit is completed from the positively energized conductor 163, through interlocks RR3-in, y(lO-REG., and J l-in and conductor 156 through the actuating coils of the switches R4 and RR4, as previously describedn The initial coil-energizing circuits of the switches M1, and G1 are also opened by reason of the disengagement of the contact segment 253 from the corresponding control finger 166 during the transitional movement of the master controller, although the opening `of these switches is prevented until the switch is closed, by reason of an interlocking arrangement similar to that hereinbefore set forth in connection with the transition from series parallel acceleration of the motors, such interlocking arrangement comprising the positively energized conductor y 174, interlocks ,T1-out and M'l-in and conductors 277 and 172 to the actuating coils of the switches M1 and G1, thus insuring that the switch J 1 shall be closed before the holding circuit just described for the switches M1 and G1 is interrupted by the exclusion of the interlock J l-out upon the closure of the switch J 1.

As soon as the master controller reaches its initial series position f', one circuit is cornypleted from the contact segment 232 through control finger 279, conductor 280, train-line conductor 281, conductor 282, actuating coil 283 of the control relay CR and conductor 284 to the negative conductor 29.

As soon as the interlock drum ID passes beyond its position c, a plurality of contact segments 285 and 286 that respectively correspond to contact segments 247 and 239 engage control fingers 290 and 293, whence one circuit is completed through conductor 291, Coperating contact member 292 of the control relay CR in its upper or closed position, interlock G1-out and thence through the off' coil in accordance with a circuit that has hereinbefore been traced, while the other circuit is completed from control finger 293 through conductor 294, coperating contact members 295 of the control relay,- conductor 242 and thence through the actuating coil On as previously set forth.

When the controller PK occupies its position f, the control finger 244 engages contact segment 285 and the control fingers 272 and 240 still engage the contact segment 239.

Upon actuation of the master controller to its position g', the contact segment 232 engages control finger 233, whence the control finger 244 is energized to complete the circuit of the actuatin coil Off and thus permit movement of the controller' PK to its position g, whereinl .the control fingers 272 and 240 become disengaged from contact segment 239 and control fingers 238 and 293 engage contact segment 266 to maintain the energization of the on actuating coil.

Upon movement of the master controller through its positions h', z and j', the control ngers 156, 149 and 255 are successively energized, thus completingthe corresponding circuits to permit a corresponding stepby-step actuation of the controller PK.

In the final position k of the master controller," the contact segment 232 engages control finger 62, whence circuit is completed through conductor 64 as hereinbefo're described, contact member 301 of thel changeover switch CO, conductor 302 andV control finger 303 which engages contact segment 285 and thus effectsA the movement of the controller PK to its final position k.

As previously mentioned, the foregoing description considers the case wherein the regenerative machines are operated at a relatively high speed so that initial parallel regenerative operation is permissible.

However, if the speed of the machines is sufficiently low to preclude the possibility of employing parallel-connected regeneration even though the controller PK is actuated to its final parallel position e to fully excite the main field windings, the further movement of the master controller MC will effect the energization of the control relay and, consequently, of the actuating coils On and Ofi and thus effect a step-by-step movement of the controller PK until the voltage across the series-related main armatures preferably exceeds the supply-circuit voltage by a predetermined amount, whereupon the relay device will be actuated to its proper position to close the line switch LS1 in accordance with the previously traced circuits, and regeneration will take place from that point on to the final position of the controller PK, in the manner already described.

Although I have shown and described my high-current relay l in connection with a certain type of system that is more or less complicated, it is believed that a materially simpler set of circuit connections would not fully set forth all the advantages accruing from the use of my invention.

I do not wish to be restricted to the speciiic circuit connections and arrangement and location of parts herein set forth, as

' various modications thereof may be effected without departing from the spirit and scope of my invention and I desire, therefore, that only such limitations shall be imposed as are indicated in the appended claims.

I claim as my invention 1. In a system of control, the combination k with a supply circuit 'and a momentumdriven dynamo-electric machine, of means for connecting the machine to the supply 3. In a system of control, the combination with a supply circuit and a momentumydriven dynamo-electric machine, of means for connecting the machine to the supply circuit, means for normally maintaining the regenerated current above a predetermined lower value, and other means operative only under free-running conditions of the machine for preventing the regenerated current from exceeding a predetermined higher l value. Y

4. Ina system of control, the combination with a supply circuit and a momentumdriven dynamo-electric machine, of means vfor connecting the machine to the supply circuit, a relay device adjusted to lift to normally maintain the regenerated current above a predetermined lower value, and a second relay device adjusted to lift at a predetermined higher current value to prevent a regenerated current in excess of vsaid higher value only under free-runningl conditions of the machine.

5. In a system of control, the combination with a supply circuit, and a plurality of momentum driven dynamo electric machines, of means for connecting the machines to the supply circuit, a relay device adjusted to lift to normally maintain the regenerated current above a predetermined lower value, and a second relay device adjusted to lift at a predetermined higher current value to prevent regenerated currents yin excess of said higher value only when the machines are connected in full-parallel or full-series relation.

6. In a system of parallel-series regenerative control, the combination with a. supply circuit, and a plurality of momentum-driven dynamo-electric machines severally having armatures and field windings, of means for separately exciting said field windings, means for connecting the machines to the supply circuit, resistors initially connected in circuit with said machines, means controlled by armature current for gradually spectively connected in circuit with the groups of corresponding armatures and field i windings, a relay device controlled' by the plete] armature current for gradually excluding said resistors from circuit as the machine speed decreases during both parallel vand ser1es machine operation, and av second relay device for preventing the regenerated currents exceeding a predetermined value whenever the resistors are substantially comexcluded from circuit.

8. n a system of control, the com-bination with a supply circuit, and a momentumdriven dynamo-electric machine having an armature and a field winding', of' means for separately exciting said field winding, means for varying such excitation, means for connecting the machines to the supply circuit, means for preventing the regenerated current exceeding a predetermined value, an auxiliary circuit, and means for rendering said auxiliary circuit active only after said predetermined current value obtains and the field-winding excitation is relatively Weak.

9. In a system of control, th-e combination with aesupply circuit, and a momentumdriven dynamo-electric machine having an armature and a field Winding, of means for separately exciting said field winding, a variable resistor in the exciting circuit, means for connecting the machine to the supply circuit, means for preventing the regenerated current exceeding a predetermined value, an auxiliary circuit, and means for rendering said auxiliary circuit active only after said predetermined current value obtains and said resistor is fully included in circuit.

10. In a system of parallel-series regenerative control, the combina-tion with a supply circuit, and a plurality of momentum-driven dynamo-electric machines severally having armatures and field windings, of separate means for exclting said field windings, re-

sistors in the respective exciting circuits, a controller for simultaneously decreasing the active value of said resistors as the machine speed decreases during both parallel and series machine operation, means for connecting the machines to the supply circuit, means for preventing the regenerated current exceeding a predetermined value, an auxiliary circuit, and means for rendering said auxiliary circuit active only after said predetermined current value obtains and said controller occupies either its initial parallel or initial series position.

11. In a system of control, the combination with a supply circuit and a momentumdriven dynamo-electric ma-chine'having an armature and a field winding, of means for separately exciting said field winding, means for varying such excitation, means for connecting .the machines to the supply circuit, means for normally maintaining the regenerated current above a predetermined lower value, other means operative only under free-running conditions of the machine for preventing the regenerated current `exceeding a predetermined higher value, an auxiliary clrcuit, and means for rendering said auxiliary circuit active only after said predetermined higher current value obtains and lthe field-winding excitation is relatively wea 12. In a system o parallel-series regenerative control, the com ination with a supply circuit, and a lurality of momentum-driven dynamo-electric machines severally having armatures and field windings, of separate means for exciting said iield windings, resistors in the respective exciting circuits, a controller for simultaneously decreasing the active value of said resistors as the machine speed decreases during both parallel and series machine operation, means for connecting the machines tothe supply circuit, relay means for normally maintaining the regenerated current above a predetermined lower value, relay means for preventing the regenerated currents exceeding a predetermined higher value whenever the resistors are substantially completely excluded from circuit, an auxiliary clrcuit, and means for rendering said auxiliary circuit active only after said predetermined higherY current vvalue obtains and said controller occupies either its initial parallel or initial series position. i

In testimony whereof, I have hereunto subscribed my name this 29th day of March,

CHARLES C. WHITTAKER.

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