| 摘要 |
PROBLEM TO BE SOLVED: To provide a highly reliable automatic operation type submerged pump capable of surely stopping, without having to provide an electrode and a float type water level detector which may be damaged, when handling them outside the pump and detecting a draught water flow operation condition due to the reduction of water level by monitoring other electric motor operation parameters, without relying on conventional current values to control operation. SOLUTION: This automatic operation type submerged pump for controlling the operation of a motor 1 by detecting a water level is provided with a phase difference detection means for detecting the difference in phases between a voltage and a current supplied to the motor 1, and a pump control means for stopping the automatic operation submerged pump PC, when the difference in phase reaches a prescribed threshold.
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