Tubular Motor has 4 cases of excessive current:

1. The power supply voltage is too high
When the power supply voltage is too high, the motor back electromotive force, magnetic flux, and magnetic flux density will increase accordingly. Since the size of the iron loss is proportional to the square of the magnetic flux density, the iron loss increases, causing the core to overheat. The increase in magnetic flux also causes the component of the excitation current to increase sharply, resulting in an increased copper loss in the stator winding and overheating of the winding. Therefore, when the power supply voltage exceeds the rated voltage of the motor, the motor will overheat.

2. The power supply voltage is too low
When the power supply voltage is too low, if the electromagnetic torque of the motor remains unchanged, the magnetic flux will decrease, and the rotor current will increase accordingly, and the load power component in the stator current will increase accordingly, causing the copper loss of the winding to increase, resulting in the stator and rotor The winding is overheated.

3. Asymmetrical power supply voltage
When one phase of the power cord is broken, the fuse is blown in one phase, or the corner of the knife starting device is burned to cause one phase to fail, it will cause the three-phase motor to go single-phase, causing the running two-phase winding to overheat through high current and even burn.

4. Unbalanced three-phase power supply
When the three-phase power supply is unbalanced, the three-phase current of the motor will be unbalanced, causing the winding to overheat.