G04C3/00—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means
G04C3/02—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a pendulum
G04C3/027—Electromechanical clocks or watches independent of other time-pieces and in which the movement is maintained by electric means wherein movement is regulated by a pendulum using electromagnetic coupling between electric power source and pendulum
C—CHEMISTRY; METALLURGY
C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS