Title:
POWER-SAVING CIRCUIT OF MOTOR
Document Type and Number:
Japanese Patent JPS5863091
Kind Code:
A
Abstract:
PURPOSE:To enable accurate discrimination of a loaded time from an unloaded time, by varying a detection reference value in proportion to the fluctuation of a supply voltage in the case of a change from the unloaded state to the loaded, and by fixing the detection reference value in the case of a change from the loaded state to the unloaded. CONSTITUTION:A comparison circuit 5 conpares a load current delivered from a current detecting circuit 4 and flowing to an induction motor 2 with a reference voltage delivered from a reference voltage switching circuit 10. A gate pulse circuit 8 controls a phase control element 3 so as to impress on the induction motor 2 a full voltage at a loaded time and a low voltage at an unloaded time according to the output of the comparison circuit 5. The reference voltage switching circuit 10 delivers a reference voltage varying in proportion to the fluctuation of the voltage of a power source 1 obtained via a voltage-dividing circuit 9 in the case of a change from an unloaded operation to a loaded operation, while delivering a fixed reference voltage 6 in the case of a change from the loaded operation to the unloaded operation.
Inventors:
KANARI MASAYUKI
UNO TAKESHI
UNO TAKESHI
Application Number:
JP15877881A
Publication Date:
April 14, 1983
Filing Date:
October 07, 1981
Export Citation:
Assignee:
HITACHI LTD
International Classes:
H02P29/00; H02P23/00; (IPC1-7): H02P7/00
Attorney, Agent or Firm:
Akio Takahashi