Why can’t a 60Hz motor be connected to a 50Hz power supply?

Since the inductance L of a motor winding is constant, and the inductive reactance XL = 2πfL, it can be seen from this formula that when L remains constant, the frequency f is proportional to the inductive reactance XL; the lower the frequency f, the smaller the inductive reactance XL. Therefore, connecting a 60Hz motor to a 50Hz power supply increases the excitation current, causing severe heating and preventing it from operating properly.

Isn’t a 60HZ motor an inverter-driven motor? Why can’t it operate at 50HZ? Where did it say it can’t be used?

A motor with a rated frequency of 60Hz connected to a power supply with a frequency of 50Hz: 1. The frequency decreases, which reduces the inductive reactance resulting from the coil and core, leading to an increase in the starting and excitation currents. In severe cases, it can damage the motor ； 2. In the design of some motors, the magnetic flux in the core is close to saturation; in such cases, a decrease in frequency may not result in an increase in starting and excitation currents. But the cooling performance declines as a result, causing the motor temperature to rise ； 3. A decrease in frequency leads to a reduction in speed; if the motor’s coils and core are of the type where the current does not rise significantly enough to cause damage to the motor, then the torque will also not increase. The result of a constant torque with decreasing speed is that the motor’s output power is reduced by about 20%.