Resonant motor unit and electric device with resonant motor unit

Abstract

A resonant motor unit that has a resonant motor, a control unit, a measurement unit, and an evaluation unit is described. The control unit drives the resonant motor at a driving frequency, short-circuits the resonant motor during at least a first short-circuiting phase in successive driving cycles and concludes the first short-circuiting phases by switching off the current flow through the resonant motor at least at a predetermined first time instant within the driving cycles. The measurement unit successively measures at least a first voltage signal provided by the resonant motor at the predetermined first time instant, and the evaluation unit for determines whether the first voltage signal has changed between successive measurements.

Dependencies are inferred from the claim text.