Working principle of motor protector

The classic star-delta starting method of the motor is mainly to protect the thermal relay. If the thermal relay is used to protect the large motor, the large wire will have a break point, that is, the screw wiring problem in and out of the thermal relay, which is prone to heat and failure points. If the fuse and thermal relay are not used, and the motor integrated protector is used to achieve it, because the protector is a through-type, the break points of the large wire can be reduced, thereby reducing the heat and failure points.

When using a motor protector, you must pay attention to the wiring of the control circuit to ensure the normal operation of the machine. It can replace a low-voltage electrical appliance such as a circuit breaker, contactor, thermal relay, fuse, etc.

The installation steps of the motor protector are as follows:

1. According to the installation location requirements and protection function needs, reasonably select the motor protector model and its various protection action parameter settings;

2. Install correctly according to the product manual, connect the terminals correctly according to their purpose, connect the working power supply before the control circuit, and make sure the nominal voltage is consistent with the actual voltage;

3. When the motor protector is equipped with a current ratio transformer, if an ammeter display is required at the equipment site or in the control room, it is best to equip it with another current transformer, otherwise it will affect the current display of the phase equipped with the ammeter;

4. When installing a split protector, do not use the matching transformers and display parts with different numbers together;

5. It can be improved according to user requirements. The output of the analog 4-20 mA interface should match the connected device;

6. Correct grounding. When the low-voltage system is a TN-C protection system, the grounding protection line of the equipment on the load side of the protector must be changed to an independent protective grounding according to the TT system. The neutral line must not be grounded repeatedly and must not be used as a protection line.