SCHALTUNGSANORDNUNG ZUR UEBERWACHUNG EINER ELEKTROMAGNETISCH BETAETIGTEN KUPPLUNG

摘要

A switched current source 3 drives an electromagnetic clutch 1. The current flowing through the electromagnet is monitored, and is kept between two thresholds by a Schmitt trigger 5 controlling the current source. The thresholds depend on whether the clutch is to be engaged or disengaged. The frequency fM of the switching (or of the current in the winding) is measured, and compared 10 to a reference frequency fR to verify that the clutch is positioned correctly. The circuit is suitable for use in a printing press.