(under subclass 68) Subject matter wherein the motor structure is either responsive to a predetermined frequency of the signalling or actuating current or operates at a speed corresponding to the frequency of the actuating current.
SEE OR SEARCH THIS CLASS, SUBCLASS:
94, for periodic switches with vibratory reeds tuned or resonant at a particular frequency.
101, below, for alternating current responsive switches which are synchronous frequency responsive.
SEE OR SEARCH CLASS
318, Electricity: Motive Power Systems, appropriate subclasses, for electric motors having means for varying or adjusting frequency of the current applied thereto usually for speed control. See
503, and the search notes thereunder for the general field of search for motors with armature current frequency or pulsation control. 334, Tuners,
20+, for motor operated tuners, particularly subclass 21 for predetermined frequency selector tuners.
361, Electricity: Electrical Systems and Devices,
113, for safety and protective systems which are frequency responsive and subclasses 182+ for relay systems which are frequency responsive.
