Electric motor circuit for vehicle window control - has thyristor controlled overload protection withstanding short periods of overload

摘要

The protection circuit for electronic motors operates when the supply current to the motor exceeds a given threshold level. The circuit is designed to allow easy introduction into the supply system, to accommodate period overloads and the spread of the relay characteristics upon which the circuit is based. The threshold can be altered by adjustment of the relay and is suitable for a range of applications, esp. electrically operated vehicle windows. The circuit consists of a thyristor controlling current in the relay coil and an RC delay circuit breaking the series line through the relay contacts, the line to the thyristor being taken through a switch operating when the motor function has been completed.