Patent GB-515234-A (GB)
Title: Improvements in and relating to control systems for electrically operated elevators
IPC: B66B1/50
Filed: 1938-06-13
Abstract: 515,234. Motor control systems for lifts. BRITISH THOMSON-HOUSTON CO., Ltd. June 13, 1938, No. 17529. Convention date, June 12, 1937. [Class 38 (iii)] Relates to the control of electric motors for lifts, involving low-speed and high-speed decelerating means brought into action responsive to the position of the lift. With a car controller 27 in its off position a relay 46 is energized to open contacts 47 and close contacts 48, and at the first position 53 a relay 54 is energized to open contacts 56, 57. At the second position 58 of the controller coils 21 and 60 are energized in series, the former connecting the field 15 of the generator 12 supplying the driving motor 11, to the supply with parallel resistances 22, 24 in circuit, and the latter effecting release of a brake 70a. The coil 60 also opens contacts 50 to deenergize the relay 46 whereby contacts 47 close and contacts 48 open after a time interval. In the position 78 of the controller a relay 79 is energized to connect a resistance 25 in parallel with the resistances 22, 24, and strengthen the generator filed. In the final position 91 of the controller a relay 92 is energized to connect a resistance 23 in parallel with the resistances 22, 24, 25, and futher accelerate the driving motor. The relay 92 also energizes a relay 100 provided the elevator speed is sufficient to cause closure of a switch 105. The relay 100 shortcircuits the resistances 22-25 to give full speed. When the controller is thrown to its off position, and a vane 44 positioned in the hatchway at a certain distance from the next floor passes between inductively related coils of thermionic device 35, a relay 112 operates to de-energize coils 92 and 100. Thus resistances 22, 24, 25 are reinserted in parallel in the generator field circuit, and the elevator decelerates to a low speed. Levelling devices 38 and 37 then take control, the former co-operating with a vane 39 when the car is about two feet from the floor to energize a coil 119 to open a switch 89 which de-energizes a coil 79 to disconnect the resistance 25, and the latter co-operating with a vane 40 at a distance of eight inches from the floor to energize a coil 124 which disconnects the resistance 24. As the device 38 leaves its vane 39 the coil 119 is de-energized and the field 15 is disconnected, and the brake applied. In the event of overrun a device 36 effects reverse energization of the field 15 until the floor is reached and thereupon the elevator is stopped. For one floor runs, the car controller is returned to its off position before the contacts 48 of the relay 46 open and thus the relay 129 is energized and energization of the relay 100 is prevented. The car accelerates with the resistances 22, 25 in the generator field circuit. Contacts 111 on the relay 129 close the circuit through deceleration devices 32, 33, which cooperate with respective vanes 41, 42, situated nearer to the corresponding floor than the vanes 43, 44. When the device 33 reaches its vane 42 a coil 134 is energized to open the switch 98 and de-energize the coil 92. This opens the switch 94 leaving the resistances 22, 24, and 25 in the generator field circuit. Deceleration then proceeds as before. Specifications 401,389 and 406,655 are referred to.