PURPOSE: To prevent the detection error due to a minute signal by installing a main control circuit in which the speed information measured in a pulse interval measuring circuit is feedback-inputted and the speed control of an electric motor is carried out on the basis of the speed information.
CONSTITUTION: An induced voltage including the throttle higher harmonic ripples is generated in a searching coil wound on a motor stator. The induced voltage signal is taken out as the speed signal in a speed signal generating circuit 17, and feedback-input as speed information into a main control circuit 16 through a pulse interval measuring circuit 15, and a speed feedback control system for a sealed type motor-driven compressor 13 is formed. Therefore, the detection error due to a minute signal can be prevented.
SATO YUTAKA
SAKAI MASATOSHI
TAKIMOTO SUNAO
