Movable barrier operations method and apparatus

摘要

The device has a motor (20) mechanically coupled to a barrier (10) by a barrier coupling device (21). A dummy electrical load (22) is operationally coupled to the motor by a commutator (23). The commutator selects an electrical load according to an input from sensors (25-27) to control braking of the motor when the barrier is shifted from a raised position to a lowered position. Independent claims are also included for the following: (a) a device for controlling movement of fire-proof door (b) a process for controlling movement of a fire-proof door.