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Overload protection principle of motor protector

What is overload? If the motor is overloaded for a long time, the winding temperature of the motor will rise and exceed its allowable value, resulting in brittle insulation material edges of the motor, shortened life, and even burnt out the motor. This phenomenon is called overload fault.

Then, with overload protection motor protector, and how to play a protective role?

JLW

 

When the motor is rated current, the motor will be rated temperature rise, this time the motor protector will not operate. When the overload current is small, the motor protector only needs to set the light current value. Once the current is lower than the set value of the protector, it will output a signal to the contactor, so as to disconnect the power supply on the circuit and protect the motor. When the overload current is large, the motor protector will act in the first time, making the contactor disconnect the power supply. As for this time accuracy, according to their actual protection requirements to choose the corresponding accuracy of the protector. Different types of protection, the accuracy range is not the same.

In addition, the motor protector will also take into account the motor’s thermal inertia. Therefore, the motor protector will not be affected by the impact of short-term overload current and instantaneous action of the motor. However, when the motor short circuit fault, the first instantaneous action. Therefore, the proper use of motor protector, you can effectively prevent the motor in the failure of operation to burn out the motor.

It should be noted that, although short-circuit, over-current, overload protection and other current protection category, but the fault current action value, protection characteristics, protection requirements and the use of components are different, so the concept between them can not be exchanged, can not be confused!


Post time: Nov-25-2019
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