Partial discharge inception voltage (PDIV) detection is an essential test method for evaluating the insulation performance of random wound inverter-fed motor stators. As an important parameter of pulse-width modulation voltage, the effects of pulse width on the PDIV of interturn insulation and interphase insulation in random wound inverter-fed motors are noteworthy. In this paper, the PDIV distribution laws of interturn insulation and interphase insulation in motor under different pulse widths were studied in the frequency of 50 Hz, rise time of 75 ns, and pulse widths within of 0.5-20 μs. The results show that when unipolar pulse square waves are input into random wound inverter-fed motors for PDIV testing, the overall trend of PDIV decreases as the input pulse width increases. Due to the combined effect of overvoltage from the rising and falling edges of short pulses, a turning point occurs in PDIV at a pulse width of 4 μs. It is necessary to consider the effects of pulse width and overvoltage and select appropriate pulse widths to obtain conservative values of stator insulation PDIV when conducting the PDIV test of interturn insulation and interphase insulation in random wound inverter-fed motor under unipolar pulse.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |