When a three-phase motor lacks one phase of electricity, an effective magnetic field cannot be formed inside the motor, which can quickly burn out the motor.

What is the specific reason for the lack of phase electricity? How to avoid it?

External reasons for the lack of phase current in the phase motor

1. Loose wiring screws in the motor junction box

2. Loose or oxidized connection points in three-phase power circuits

3. Poor contact of contactor contacts

4. The contact resistance is very high

5. The fuse in the fuse is disconnected or not securely connected

Internal reasons for the lack of phase current in three-phase motors

Measure the DC resistance of the three-phase winding. If one phase has a high or infinite resistance value, then this winding is the open circuit phase.
Solution measures

Thermal relays with phase failure protection can be used for phase failure protection.