To securely prevent flow-in of excess current to an electric motor and to securely stabilize supply oil pressure to a hydraulic actuator in an electric hydraulic work machine which makes the three-phase inductive electric motor driven by star delta starting system a power source of hydraulic driving.
A control circuit is provided with an electromagnetic switching valve 40 interrupting and interruption-releasing supply of pressure oil to the hydraulic actuator; a power supply circuit 30 switching power supply to the three phase inductive electric motor 1 to a delta circuit when switching time elapses from starting time; a timer relay 35 provided with a switching time setting means for setting switching time; and an interruption release limiting means 35c for supplying power to the three phase inductive electric motor 1 by using a star circuit at starting time, and limiting output of an interruption release signal to the electromagnetic switching valve 40 until switching time elapses from starting time of the three phase inductive electric motor.
MATOBA NOBUAKI
YUME HIDEAKI
SHIMODA WATARU
IKEDA YOSHIHIRO
| JPH10271863A | 1998-10-09 | |||
| JPH11112990A | 1999-04-23 | |||
| JP2000175487A | 2000-06-23 |