The characteristic of frequency conversion electromotor

From;  Author:Stand originally

1, electromagnetism design

To common asynchronous electromotor, the performance data that when be being designed again, basically considers is the overload ability, function that start, efficiency and power factor. And frequency conversion electromotor, as a result of critical turn poor rate inverse ratio at power source frequency, can be in critical turn poor rate is adjacent 1 when start directly, accordingly, overload ability and the function that start does not cross much consideration in need, and the crucial problem that should solve is how to improve electromotor to be opposite the suiting that is not sine wave power source ability. Means is as follows commonly:
1) as far as possible reduce stator and rotor resistance.
Reduce stator resistor to be able to be reduced base wave copper bad news, increase in order to offset the cupreous cost that Gao Cixie wave causes
2) to restrain electric current medium tall second harmonic, need to increase the inductance of electromotor appropriately. But rotor chamfer leakage is fought bigger effect of its collect skin is big also, bad news of copper of Gao Cixie wave also increases. Accordingly, the size that electromotor leakage fights wants the rationality that give attention to two or morethings matchs to the impedance inside whole timing scope.
3) of frequency conversion electromotor advocate magnetic circuit designs not saturated condition commonly, it is to consider Gao Cixie wave to be able to deepen magnetic circuit saturation, 2 it is to consider to be when low frequency, output torsion to rise and heighten the output tension of transducer appropriately.

2, structural design

Again when the structure is designed, also basically be character of power source of consideration blame sine the influence of the respect such as means of refrigeration of the insulation system of electric machinery, oscillatory to frequency conversion, noise, note the following problem commonly:

1) insulation grade, be F class commonly or taller, enhance right insulation and turn insulation strength, should consider to be isolated from particularly impulse withstand the ability of voltage.
2) problem of the vibration to electric machinery, noise, want mature electrically operated mechanism the tigidity that reachs whole, endeavor to increase its natural frequency, produce resonance phenomenon in order to keep away from with each force wave.
3) cooling means: Use commonly force ventilated refrigeration, namely advocate electric machinery comes loose the electric machinery drive that heats up fan to use independence.
4) avoid measure of axial electric current, exceed 160KW electromotor to should adopt bearing insulation measure to the capacity. Basically be asymmetry of easy generation magnetic circuit, also can produce axial electricity, when the voltaic tie that produces when place of other and high frequency heft acts well, axial electric current will increase greatly, cause bearing damage thereby, want to take insulation step commonly so.
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