Three-phase asynchronous motors are widely used in transmission equipment in daily production

What is the protective device of a three-phase asynchronous motor? It is actually a thermal relay. Refers to the structure of the motor rotor. According to the type of power supply, three-phase induction motors can be divided into DC motors and AC motors. According to different functional characteristics, it can be divided into ordinary type, electromagnetic brake type, inverter type and inverter type brake.

Three-phase asynchronous motor is a kind of motor in the motor industry, but it is also a kind of machine with wide application and development. In modern transmission system machinery, about 70%-80% of the mechanically designed transmission equipment is driven by it. The reason why the traditional three-phase asynchronous motor can be used must be because it has the characteristics of large transmission torque, simple structure, safe and reliable operation, and relatively low maintenance and management prices.

More and more motors have appeared, and as overload protection components of three-phase asynchronous motors, they are widely used in daily production of transmission equipment. So, if the motor has burned out and the thermal relay hasn't moved, is there a problem?

1. The action mechanism is stuck or the guide plate falls off. To operate, open the thermal relay cover, check the action mechanism, reposition the guide plate, and press the reset button. Check whether the action mechanism is flexible.

2. The bimetal is permanently deformed by the short-circuit current in the heating element, so the combustion thermal relay of the motor can work when the motor is not overloaded. In this case, replace the bimetal, then adjust.

3. The rated value of the thermal relay of the three-phase asynchronous motor is too large, and the contacts are not in good contact, which is not good for the society. At this point, businesses can adjust the ratings to remove dirt or oxides on the contact surfaces.

4. When repairing the thermal relay with a three-phase asynchronous motor, due to negligence, the bimetal is reversed, or the bimetal and the heating element are used incorrectly. In this case, overcurrent flows through the heating element, the bimetal cannot push the guide rail, and the motor is overloaded and burned, but it is not the operation of the thermal relay. Handle, inspect and adjust the orientation of the bimetal or place a suitable heating element and bimetal on it.