Spiral spring drive type electronic clock - has control circuit which makes rotor rotate in predetermined direction at speed greater than desired rotation speed when delay of actual angular position of rotor is greater than predetermined delay

摘要

The clock has a tracking circuit (7) which actuates the application of a retarding torque to the rotor (3a) of an electric-machine converter (3) so that the rotation speed of the rotor will become less than a desired rotation speed. The converter supplies electrical energy to the tracking circuit. The delay of the actual angular position of the rotor with respect a desired angular position is determined. A control circuit operates the tracking circuit to apply a predetermined drive torque to the rotor to the make the rotor rotate in a predetermined direction at a speed higher than the desired rotation speed, when the determined delay is greater than a predetermined delay.