Pump device

Abstract

Abstract PURPOSE:To reliably protect a pump even when a temperature relay fails to operate, by providing an abnormality detecting means for detecting abnormality of a temperature detecting means and a motor stopping means for stopping a motor according to an output signal from the abnormality detecting means. CONSTITUTION:In a shut-off operation of a pump 2, water temperature in the pump 2 is rapidly increased, and resistance of a thermister 17 is decreased. A partial voltage (a) becomes higher than a partial voltage (c). A comparator 25 generates a H signal, and a hold circuit 38 feeds a H signal to a NOR circuit 40 and hold the signal. Accordingly, even when a pressure switch 10 and a flow switch 11 generate H signals, the NOR circuit 40 continues to generate a L signal, and a motor 1 is therefore stopped. Further, when current across the motor 1 is excessive, an output (e) becomes greater than a partial voltage (f) through CT 31 and rectifier bridge 32. A comparator 33 generates a H signal, and the hold circuit 38 generates a H signal and hold the signal, thereby stopping the motor 1. Thus, the pump may be reliably protected even when a temperature relay fails to operate.

Inventors

• 👤 Sakue Yamamoto
• 👤 作衛 山本
• 👤 Toshio Oka
• 👤 岡　俊雄

Bibliographic Details