Protective device for a controlling system of a sewage pump

Abstract

A protective device for a controlling system of a sewage pump has a protective unit to protect a start capacitor and to avoid the start capacitor from burnout when an overload is occurred by actuating power source or when a transient voltage is occurred by malfunction of a controlling circuit after actuating the sewage pump. Therefore, the start capacitor is certainly protected and significantly improved in lifespan. The characteristic of this invention is that the protective device comprises an analogic or digital electronic circuit with a cutter efficiency.

1 . A protective device for a controlling system of a sewage pump with a start capacitor and a run capacitor, the protective device comprising a protective unit having an analogic or digital electronic circuit with a cutter function providing a protective efficiency to avoid the start capacitor in the sewage pump from burnout. 
   
   
       2 . The protective device as claimed in  claim 1 , wherein the protective unit further comprises:
 a first terminal served as a signal input end of a power source;   a second terminal kept at NC status with the first terminal to control the start capacitor and the run capacitor;   a third terminal controlling the start capacitor; and   a fourth terminal kept at NO status with the third terminal to control the start capacitor and the run capacitor.