一、the difference of general motor and frequency conversion motor structure
1、insulation level is higher
General frequency conversion motor insulation class is F or higher, strengthen the insulation and line turn insulation strength, especially considering the ability of impact resistance voltage insulation.
2、 frequency conversion motor vibration and noise requirements higher
Frequency conversion motor, we must give full consideration to the motor components and overall rigidity, trying to improve its natural frequency, in order to avoid and every force wave resonance phenomenon.
3、 frequency conversion motor cooling in a different way
Frequency conversion motor generally adopts forced ventilation cooling, namely USES the independent main motor cooling fan motor driver.
4、 different requirements for protection
The capacity of more than 160 kw variable frequency motor bearing insulation measures should be adopted. Mainly produces magnetic circuit asymmetry, also can produce shaft current, while the rest of the high frequency component generated by the current role in combination, shaft current will increase greatly, which can lead to bearing damage, so commonly used insulation measures. Of constant power variable frequency motor, when more than 3000 / min speed, high temperature resistant special grease should be adopted, to compensate for the temperature of the bearing.
5、 different cooling system
Frequency conversion motor cooling fan with independent power supply, to guarantee the continuous cooling capabilities.
二、the difference of general motor and frequency conversion motor design
1、the electromagnetic design
For ordinary asynchronous motor, the performance of the main consideration when the design parameter is the overload capacity, starting performance, efficiency and power factor. And frequency conversion motor, because of the critical slip inverse ratio at power frequency, you can directly start when critical slip is close to 1, therefore, overload capacity and startup performance is not need to think too much, and to solve the key problem is how to improve the motor's ability to adapt is a cool wave power.
2、 the structure design
In structure design, main is to consider the is dazzle wave power characteristics of variable frequency motor insulation structure, vibration and noise, the influence of cooling, etc. |
