GB370097A - Improvements in and relating to starting devices for electric motors - Google Patents

Abstract

370,097. Master control of motors; electromagnetic switches. BRITISH THOMSON-HOUSTON CO., Ltd., Crown House, Aldwych, London, and BOURNE, S. N., Birding- bury, Rugby. Feb. 4, 1931, No. 3591. [Classes 38 (iii) and 38 (v).] When a motor A is started consequent upon closure of start button 11, contactors 2, 5 are latched in so that they do not open upon failure of voltage. Depression of button 11 energizes coil 2a and closes contactor 2. Line voltage is thus impressed on coils 6a, 7a, 8a, causing contacts 6, 7, 8 to move to the left. Coil 1a is thus energized over contact 6 and causes contactor 1 to close, and maintains itself over auxiliary contact 1x. As coil 6a is now shorted, contact 6 moves to the right and coil 3a of contactor 3 is energized. Acceleration proceeds by the sequential shorting of coils 7a, Sa, movement of contacts 7, 8, energization of coils 4a, 5a and closure of contactors 4, 5. Stopping can only be effected by closure of stop button 12 or overload contacts 9 causing energization of unlatching coils 2b, 5b of contactors 2, 5. An auxiliary contact 3x prevents re-energization of coil 2a until after opening of contactor 3. A construction of latched contactor is shown in Fig. 2. The operating coil L when energized attracts its armature K and the end thereof engages the latch M and is held in the attracted position until the release coil O is energized.