The characteristics of variable frequency motor

1,the electromagnetic design For ordinary asynchronous motor,and the design main consideration of the

performance 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 ability to adapt the

motor of the non sine wave power. Generally as follows: 1) as far as possible,the reduction of the

stator and rotor resistance. Reduce the stator resistance can reduce the fundamental wave copper consumption,to compensate for wholesalemotor.blogspot.com higher harmonic caused by copper consumption increase 2) to suppress the higher harmonic current,should be appropriate to increase the inductance of the motor. But rotor slot leakage resistance is larger the skin effect is also big,higher harmonic copper loss also increased. Therefore,the size of the leakage reactance of the motor should give attention to two or morethings arrives the rationality of the impedance matching within the whole speed range. 3) the main magnetic circuit of frequency conversion motor generally designed to unsaturated state,one is to consider will deepen higher harmonic magnetic circuit saturation,2 it is to consider at low frequency,in order to improve the output torque and appropriate to increase the output voltage of inverter. 

2,the structure design Structure design,main is also considering the non-sinusoidal power characteristics of variable frequency motor insulation structure,the influence of vibration and noise cooling mode,generally pay attention to the following questions: 1) the insulation class,generally for perkins diesel generator set F or higher,strengthen the insulation and line turn insulation strength,especially want to consider the ability of impact resistance voltage insulation. 2) to the problem of vibration and noise of the motor,the motor should be fully considered component and overall rigidity,trying motor

laminationto improve its natural frequency,in order to avoid and every force wave resonance

phenomenon. 3) cooling method: generally adopts the forced ventilation cooling,namely USES the

independent main motor cooling fan motor driver. 4) measures to prevent shaft current,the capacity of

more than 160 kw 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 often insulation measures. 5) www.facebook.com/guohong.trading to

the constant power variable frequency motor,when the rotation speed of more than 3000 / min,high

temperature resistant special grease should be adopted,to compensate for the temperature of the

bearing