Linear motors for underground passenger carriage - has acceleration and deceleration motor each side with constant speed motor between

摘要

The underground passenger carriages are required to stop accurately in front of access lifts and platforms, as controlled by a computer. The carriage doors open vertically up and down. Each carriage has three linear motors on its chassis (110). The two outer or side motors (122, 123) have their inductors (106, 121) fixed to the track (R, R'). These are supplied with d.c. generating a magnetic field. They are also supplied with a.c. in the form of positive or negative half-phases, depending on whether the carriage is accelerated or decelerated. A centrally placed linear motor (124, 125) is also fed with a.c. this providing constant speed.