Automatic reset for servomotor circuit power failure - using reservoir capacitor switched across motor by transistors on relay

摘要

A circuit for resetting a measurement mechanism, esp. for an electrical servo device with a servomotor, ensures reliable resetting in the event of failure of the auxiliary power supply without involving the motor in working continuously against a return spring and the resulting increased wear and speed asymmetry. For this purpose an energy storage capacitor (6) is used. This is automatically connected to the servomotor (M) by a switching circuit (8,9) if the power supply fails. A transistor switching circuit may be used. Alternatively, a bistable relay may be used as a switching circuit. This has an associated control circuit. The transistor switching circuit may contain two (8,9) transistors or four and requires a stabilised and an unstabilised voltage. The motor can be returned to a positive or negative mechanical stop.