The difference between ordinary motor and variable frequency motor
1. Insulation requirements higher
General inverter motor insulation level F or higher, to strengthen the ground insulation and turn insulation strength, in particular, to consider the ability of insulation resistance to impact voltage.
2. Frequency motor vibration, noise requirements higher
Inverter motor to fully consider the motor components and the overall rigidity (public number: pump housekeeper), try its best to increase its natural frequency, in order to avoid resonance with all the force wave phenomenon.
3. Variable frequency motor cooling method is different
Inverter motor generally adopts forced ventilation cooling, that is, the main motor cooling fan using a separate motor drive.
4. Protection requirements are different
On the capacity of more than 160KW inverter motor bearings should be used insulation measures. Mainly easy to produce magnetic circuit asymmetry, will produce shaft current, when the combination of the current generated by other high-frequency components together, the shaft current will greatly increase, resulting in bearing damage, so generally take insulation measures. Constant power inverter motor, when the speed exceeds 3000 / min, the special high temperature grease should be used to compensate for the bearing temperature.
5. Different cooling system
Variable frequency motor cooling fan with independent power supply to ensure sustained cooling capacity.