PURPOSE: To provide a device for preventing over-load of pump which can maintain the operation of a pump at the rotating speed within a range, where over-load is not generated, without stopping the pump (motor) even under the over-load condition of the pump.
CONSTITUTION: In a pump device provided with a pump and a direct current motor M1 for driving the pump, a current detecting unit 16 for detecting the motor driving current and a setting unit 17 for setting the upper limit value of the motor driving current are provided. Furthermore, an output voltage control unit 18 for comparing the detected current from the current detecting unit 16 and a set current value of the setting unit 17, and in the case that the detected current value exceeds the set current value, for lowering the voltage to be supplied to the direct current motor to lower the rotating number of the direct current motor M1 and set the motor driving current at the upper limit value or less is provided.
KOJIMA YOSHINORI
YAKABE TADASHI
| JP59194583B | ||||
| JPS6189988A | 1986-05-08 | |||
| JPS6361782A | 1988-03-17 | |||
| JPH0249983A | 1990-02-20 |