Patent GB-490369-A (GB)
Title: Improvements in or relating to electric motor control systems
IPC: B60L11/18
Filed: 1937-02-11
Abstract: 490,369. Control of motors ; electricity supply ; charging and discharging batteries. GENERAL ELECTRIC CO., Ltd., and CROFT. E. H. Feb. 11, 1937, No. 4107. [Class 38 (iii)] [Also in Group XXXV] A control system for a vehicle in which a driving motor is supplied either from a battery carried by the vehicle or from an external source, and in which the battery is arranged to be charged from the external source, comprises a first switch 24 controlling the selective con.. nection of the motor to the battery or to the external source, and a second switch 23 which controls the connection of the battery to the external source, and also isolates the motor from both sources. With the switch 24 operated to its position T under the control of coils 26, 27 controlled by switches 25, and the switch 23 in its position I, a voltage relay VRW is effective, if the track voltage is sufficient, to close its contacts VRC to energize a contactor B1W which closes its contacts B1 to complete a charging circuit for the battery from the track shoes 1-6. Auxiliary contacts B1A on the contactor B1 also close to energize contactors B2W, B3W, to connect resistances R1-R3, in parallel in the charging circuit. This charging circuit is under the control of an overload relay OCW, a reverse current relay RCVW, RCCW, and a charge control relay CCW as described in Specification 489,239, [Group XXXV]. The contactors B2W, B3W, are also controlled by contacts closed when the switch 23 is in its positions I and II, and the contactor B1W is controlled by contacts on the switch 23 and contacts 89, 90, 91, closed when a lock is operated to lock the switch 23 from movement. The charging circuit includes contacts on both the switches 23, 24. The motor circuits 22 are also completed in these positions of the switches 23, 24, to be supplied from the track in parallel with the battery. The lock on the switch 23 is operated by a key removable from the switches 25 only when these are in their off positions, and the key is removable from the lock only in its locked position. Upon operation of the switch 23 to its position II the motor circuits are opened and the battery charging circuit alone remains. In position III of the switch 23 the contactors B2W, B3W, are de-energized and the battery remains on change at a " gassing " rate with the resistance R1 alone in circuit. In position IV of the switch 23, the motor circuits remain disconnected and the battery is charged from plugs 13, 14, the resistances RI-R3 being excluded from the circuit. When the switch 24 is in its position B and the switch 23 in its position I, the motor circuits are completed to be supplied from the battery through contacts on both the switches 23, 24. In this position of the switches auxiliary contacts are effective to cut resistances 19, 20, 21, from lighting circuits L1, L2, and a compressor motor circuit CM. With the switch 23 in its other positions II-IV, the motors are disconnected from the battery. The coils 26, 27, controlling the switch 24 are under the control of interlock contacts LS1 which prevent operation while the motor circuits are closed. The contactor B1W controlling the battery charging circuit is energized in parallel with the coil 27 when the switch 24 is in its position T and the switch 23 is in its position I, and is maintained by contacts on the switch 23 when this is in its position II. Thus in position I of the switch 23 the contactor B1W can be closed only when the switch 24 is moved fully to its position T, and contacts B10 on the contactor B1W ensure that the contactor B1W is opened before the switch 24 is moved. The lock for the switch 23 carries contacts which prevent completion of the compressor motor circuit CM and ensures opening of the line switches for the motors while the switch is unlocked.