Water supply

Abstract

According to the present invention, in a water supply apparatus which converts output power of a solar cell with an inverter to drive a motor pump for pumping up water, a DC brushless motor having no sensor for detecting a position of a rotatable shaft is used as a motor for driving the pump. Further, the water supply apparatus, having a pump and a frequency converter for supplying electric power to the pump and controlling a rotational speed of the pump, includes a standard current value table in which rotational frequencies of the pump and standard current values as criteria for shutoff operation at the rotational frequencies are associated with each other, a rotational frequency detecting device for detecting a rotational frequency of the pump, a standard current value acquiring device for acquiring a standard current value corresponding to the rotational frequency detected by the rotational frequency detecting device with reference to the standard current value table, a current detecting device for detecting a current value supplied to the pump, and a comparing device for comparing the current value detected by the current detecting device with the standard current value acquired by the standard current value acquiring device.

Dependencies are inferred from the claim text.