METHOD AND APPARATUS FOR ELECTRICALLY CONTROLLING SYNCHRONOUS MOTORS

摘要

The invention concerns a method and an apparatus for actuating a plurality of synchronous motors which are connected to a common power supply and which are respectively used for displacing an element between two limit positions and have a connection for forward motion, a connection for reverse motion and a neutral connection. The connection between the forward or reverse motion connection which is in use and the power supply is interrupted by means of a limit switch which responds when the displaced element reaches a limit position. The connection between the reverse or forward motion connection which is not in use and the power supply remains interrupted during non-use. A gated switch is connected upstream of the connection for forward motion and another gated switch element is connected upstream of the connection for reverse motion. The gate input of the switch is connected to a respective control circuit which includes the respective limit switch. The advantages of the invention are that electromagnetic actuating members can be connected in parallel with this type of synchronous motor by way of limit switches without malfunctions occurring when the limit switches respond. The amount of wear of the synchronous motors is reduced and the service life thereof is thereby increased. The level of power consumption is reduced and the amount of noise developed is decreased.