Title:
OVERLOAD PROTECTING DEVICE OF STAR-DELTA STARTING TYPE INDUCTION MOTOR
Document Type and Number:
Japanese Patent JPS6059983
Kind Code:
A
Abstract:
PURPOSE:To enable to protect even at the starting time requiered for a long period by monitoring a starting current by an overcurrent detector at the starting time of star-connection wirings, and monitoring an operating current by a thermal relay at rhe normal operating time in delta-connection wirings. CONSTITUTION:A contactor 12 is opened, a contactor 16 is closed to close an operation switch 4 at the starting time of star-connection wirings, a starting current is detected by a current transformer 21 coupled via leads 17 of the contactor 16, inputted to an overcurrent relay 22, and when the starting current exceeds the prescribed value, the switch 4 is opened. The contactor 16 is opened, the contactor 12 is closed at the start completing time in delta-connection wirings, the operating current is monitored by a thermal relay 20, and when exceeding the prescribed value, the switch 4 is opened. Accordingly, even if the starting required a long period, a motor 8 can be sufficiently protected from an overload, thereby improving the reliability.
Inventors:
NAKAMURA YOUICHI
Application Number:
JP16615583A
Publication Date:
April 06, 1985
Filing Date:
September 09, 1983
Export Citation:
Assignee:
TOSHIBA KK
International Classes:
H02P1/32; (IPC1-7): H02P1/32
Attorney, Agent or Firm:
Saichi Suyama
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