GB633212A - Motor control systems - Google Patents

Abstract

633,212. Control of D.C. motors. ENGLISH ELECTRIC CO., Ltd., and CALDBECK, C. J. Nov. 27,1947, No. 31476. [Class 38 (iii)] Apparatus for controlling the direct-current driving motor of an electrically-propelled vehicle comprises a power controller for connecting the motor to an external supply, an auxiliary source of supply on the vehicle, a reversing switch for the motor having ahead and reverse positions on external supply and ahead and reverse positions on auxiliary supply, interlock'means for automatically disconnecting the power controller from the external supply when the reversing switch is moved to either of the auxiliary supply positions, and contacts on the power controller effective to connect the motor to the auxiliary supply when the controller is moved from the off position with the reversing switch in either of the auxiliary supply positions. A series traction motor 1 is adapted to be supplied from trolleys 6 and 7 or from batteries 12 and 13 which are carried on the vehicle. A reversing switch 2, which is selectively operable to ahead and reverse trolley positions, and like battery positions, is provided. When the switch 2 is. in either of the trolley positions, movement of a pedal-operated controller 8 firstly effects, through contacts 2a of the reversing switch, energization of the operating coils of line contactors 4 and 5 and then the successive energization of those of resistance-step contactors 9, 10, and 11. A switch 14 connects the batteries 12 and 13 in parallel for charging and for vehicle lighting and in series for operating the motor. To operate the motor from the batteries, the reversing switch is moved to the desired battery-position so isolating the controller 8 from the line, and rendering it ineffective to operate contactors 4, 5, 9, 10, and 11, by opening contacts 2a. Movement of the controller from the " off " position closes contacts 8a and 8b, and, with the switch 14 in the series-position, contacts 14a are closed, so that the operating-coil 15a of contactor 15 is connected across the batteries. The motor is then connected to the batteries through contactor 15 and contacts 2b and 2c of the reversing switch. The operating-lever of the reversing switch is removable when the switch is in the " off " or in one of the batterypositions only, and is used for operating the switch 14, so that operation of the seriesparallel switch is prevented if the reversing switch is in either of the external-supply positions.