The Difference Between Variable Frequency Motor And Ordinary Motor

Ordinary motors are designed based on the frequency of the mains and the corresponding power, and can only operate stably under rated conditions. Frequency converter motors are different. Frequency converter motors must overcome overheating and vibration at low frequencies, so frequency converter motors have better performance than ordinary motors in design.
The differences between the two motors are as follows:
1. The variable frequency motor can adjust the speed of the motor, thereby achieving the purpose of energy saving according to the load conditions. An ordinary motor is a device with a fixed rotation speed and cannot be adjusted.
2. Unlike the cooling system of ordinary motors, the frequency converter motor adds a forced cooling fan. The power of the fan comes from a separate power supply and cannot be output from the main motor. The function of the strong cooling fan is to ensure the cooling of the motor at low speeds.
3. The frequency converter motor with the same power is larger than the core of the ordinary motor, with more coil turns, larger wire diameter and higher insulation.

4. The frequency converter motor increases the electromagnetic load. The working point of ordinary motors is basically at the magnetic saturation inflection point. If used as frequency conversion, it is easy to saturate and generates a higher excitation current. The frequency conversion motor increases the electromagnetic load during design, making the magnetic circuit less likely to saturate.
5. The frequency converter motor strengthens the groove insulation, one is to strengthen the insulation material, and the other is to increase the thickness of the groove insulation to improve the level of withstand high-frequency voltage.
6. Measures were taken to prevent shaft current and bearing insulation measures were applied to motors with capacity exceeding 160KW. It is mainly to prevent the occurrence of magnetic circuit asymmetry and shaft current. When the current generated by other high-frequency components work together, the shaft current will increase greatly, resulting in bearing damage, so insulating measures are generally required.
7. In addition, for constant power frequency conversion motors, when the speed exceeds 3000/min, special high-temperature resistant grease is used to compensate for the temperature increase of the bearing.