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Current type Motor thermal protection thermostat switch overload. Locked rotor Test Method

Current type Motor thermal protection thermostat switch overload. Locked rotor Test Method

      Current motor thermal protection more widely used. For example: automotive, electric windows, electric motors, wiper motors, sunroof motor, blender, mixer, meat grinder and so on. When the motor is jammed, the current flowing through the coils act quickly in order to prevent overheating of the motor must be installed in the current thermal protection, common-off time is 4 to 10 seconds. If there are special requirements according to customer requirements.

There are two test methods current motor thermal protection:
       1. Analog test: the need for a stable constant current power protection and the protection to the power supply, this time should be the current overload current, after turning on the circuit breaker will trip within a predetermined time.
      2. Test Match: Before turning on the main circuit, you need to protect the device connected to the motor, and then lock the motor rotor in power, if the thermal protection parameter value is set correctly, it will disconnect the power supply within a predetermined time, first trip time may be slightly longer in after one or two cycles of work, follow-up and 20 to see a disconnect in time should be close to the same tolerances. If the 20-30 seconds, the protector still can not open the circuit, proof protectors parameters are incorrect, and you should immediately disconnect the main power supply to prevent motor burnout.
3. The overload test voltmeter:
   Objective 3.1: Pump overload long run, the detection pump motor temperature rise and thermal protection action case.
   3.2 Test procedure:
    a. After the pump impeller diameter increased, the entire pump placed in water (pump motor entirely under water) pump outlet portion does not install any device.
    b. measure the water temperature with a thermometer, and use a bridge measuring electric pump motor winding set of values, recorded.
c. The pump is powered on, the voltage at the pump is adjusted to the rated voltage of operation, when the pump is running at over load state, the current value is recorded under the boot time.
    d. Periodically stop immediately after use a bridge to measure the motor thermal state electricity group and start immediately, so you can observe whether the motor to reach thermal stability. When the thermal protector shut off, then immediately measured and recorded values ​​of motor resistance and downtime.
e. After the shutdown period, the motor temperature drops to restart temperature thermal protection, motor reboot at this time, immediately turn off the power and use a bridge measuring electrical resistance value and then immediately restart when power until the thermal protection shut off again As such repeated several times, recorded reboot (shutdown) time and motor resistance values.
    f. According to the measured initial water temperature, hot and cold motor resistance value calculated motor temperature rise of each time period, and the various parameters of temperature, voltage, current, time, etc. fill in the table.
   3. Role: In actual use, when the water pump impeller due to the foreign body coil around the pump is in overload state work, long-term operation, the motor temperature rises to within the temperature range of thermal protection, thermal protection disconnect and protect the motor.
4. Motor stall test
  4.1 Objective: When the motor stall, motor winding quickly warmed to a temperature range within the thermal protection, thermal protection if timely action for protection.
  4.2 Test procedure:
   a. The pump impeller stuck, the water pump fixed on the land, use a bridge measured resistance value of the motor windings and ambient temperature and record.
   b. adjust the voltage to the motor rated voltage, the power of the motor is energized 10 seconds immediately shut down, this time measuring motor spare set of resistors and start immediately re-boot 10 seconds, so repeatedly and record the resistance value of each time period, until the thermal protection is disconnected or the motor burned.
   c. according to the ambient temperature and the cold resistance value calculated from temperature thermal protection disconnected or motor burn time
 4.3 Role: pump at work, since leaving the foreign body stuck impeller motor stall, motor current increases rapidly, thermal protection can protect

 

 

 

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