How to distinguish variable frequency motor from ordinary motor

Variable frequency motor

Variable frequency motors are generally used in special occasions with frequency converters, and run continuously in the range of 10% ~ 100% rated speed with 100% rated load, and the temperature rise of the motor will not exceed the calibrated allowable value.

Ordinary motor

Motor is a kind of electromagnetic device which can convert or transfer electric energy according to the law of electromagnetic induction, and its main function is to generate driving torque.

Difference:

1. Heat-removal system

The variable frequency motor uses forced cooling, and the cooling fan of the main motor is driven by an independent motor, while the cooling fan of the ordinary motor is on the same line as the motor core.

2. Insulation grade

The frequency converter precision of ordinary motor is not very high, while the variable frequency motors strengthens the slot insulation, and the insulation level will be very high.

3. Electromagnetic load

The working point of ordinary motors is generally at the inflection point of magnetic saturation, which is easy to saturate if frequency conversion is done. However, the variable frequency motor increases the electromagnetic load, and the magnetic circuit is not easy to saturate.

4. Measures to prevent shaft current

Bearing insulation measures are required for variable frequency motors with power exceeding 160KW.

5. Temperature rise compensation of bearings

When the rotating speed exceeds 3000/min, the constant power variable frequency motor should use high temperature resistant special lubricating grease to compensate the temperature rise of the bearing.