DUAL TEMPERATURE DETECTING DEVICE FOR MONITORING UNDERWATER PUMP MOTOR

摘要

PURPOSE: A dual temperature detecting device for monitoring an underwater pump motor is provided to prevent the overheat of the pump motor and the damage of the motor winding by using cheap temperature sensors. CONSTITUTION: The first temperature sensor(70) detects the temperature value of a winding of a motor. The second temperature sensor(71) detects the temperature of the bearing side of the motor. The first differential amplifying section(80) removes the noise of the temperature value detected in the first temperature sensor(70), and amplifies the signal. The second differential amplifying section(81) removes the noise of the temperature value detected in the second temperature sensor(71). A float switch inputting section(60) detects the submerging of the vicinity of the motor. A reset switch(sw1) sets the temperature values of the sensors(70,71) to an initial value, and turns on a motor interrupting section(50). A temperature value setting section(10) comprises a setting switch(sw2). A controlling section(20) compares the temperature values of the first temperature sensor(70) and the second temperature sensor(71) with the predetermined temperature value to determining the interrupting time of the motor, or determines the interrupting time according to the input signal from the float switch inputting section(60).