PURPOSE: To suppress electrical noise in UHF band, which can not be suppressed sufficiently through a varistor, and to obviate the necessity of a large space by connecting a multilayer ceramic chip capacitor having small volume between the electrodes of the varistor.

CONSTITUTION: A rotor is constituted by fitting a magnetic core 7 and a communicator 8 to a shaft 6, applying a conductor coil 10 to the core 7 and applying a ring varistor 9 for suppressing electrical noise to the communicator 8. Terminals of the commutator 8 are jointed, through soldering or the like, to the terminal of the coil 10 and the electrode face of the ring varistor 9. A multilayer ceramic chip capacitor 11 is secured to the electrode face of the ring varistor 9. Consequently, capacitance of the capacitor can be selected freely and electrical noise in a desired frequency band can be suppressed.