Actuator for lift doors - has two magnetic pole groups changed over for optimum door actuating torques

摘要

The compact actuator for lift doors has rotating field magnets coupled to a drive. Two different groups of magnetic poles ensure optimum opening, closing and moving speeds of doors. The magnets are arranged as a change pole system. Pole change is ensured with e.g. a Dahlander Pole changing circuit. The magnetic system pole change is carried out with two windings with the different number of poles. Different torques are obtained by changeover of windings or by changing voltage with a phase shift control system.