PURPOSE: To prevent an elevator driving system from receiving an unwarrantable burden at the time of resuming the operation of an elevator by providing a reflux operating means for driving a motor and sending operating oil discharged from a hydraulic pump to a flow circulating means when the detected oil temperature in the hydraulic pump during the stoppage of an elevator is lower than the specified value.
CONSTITUTION: In the case of the temperature of operating oil being lowered below the specified value at the stop time of an elevator, a contact 32 is in the closed state, and a control device 9 starts its temperature control operation by an operating oil temperature signal 23a from a temperature sensor 23 so as to switch a solenoid change- over valve 31 as shown in the drawing by a change-over signal 32a. At the same time, a motor 17 is rotated by a rotation command with the rotating speed corresponding to the value of the temperature signal 23a, thus discharging operating oil from a hydraulic pump 14. As the discharge is circulated as shown by an arrow mark, the elevator is not started but the motor 17 performs idle rotation. Oil is thereby agitated, and the operating oil becomes exothermic according to the rotating speed. When the temperature is lowered considerably because of long-time stoppage; the motor 17 is idly rotated at high speed after making power supply, thus raising oil temperature to the specified value in a short time.