Title :
Failure mechanism of the interturn insulation of low voltage electric machines fed by pulse controlled inverters
Author_Institution :
Inst. for Nat. Meas. Stand., Nat. Res. Council of Canada, Ottawa, Ont., Canada
Abstract :
When induction machines are fed by fast switching inverters, their interturn insulation is electrically more stressed than in the conventional feed. When inverters are used steep voltage pulses of high repetition frequency occur. This can cause partial discharges (PDs) leading to insulation failure. The PD inception voltage and velocity of the resulting electrical ageing depend on the voltage characteristic, insulation design and temperature. These relations were investigated using laboratory models of interturn insulation, semiconductor-based pulse generator and as PD detector an UV-sensitive photo multiplier tube
Keywords :
PWM invertors; ageing; asynchronous machines; electric breakdown; failure analysis; machine insulation; partial discharges; PD inception voltage; electrical ageing; failure mechanism; fast switching inverters; induction machines; insulation design; insulation failure; interturn insulation; low voltage electric machines; partial discharges; pulse controlled inverters; temperature; voltage characteristic; Aging; Dielectrics and electrical insulation; Failure analysis; Feeds; Frequency; Induction machines; Low voltage; Partial discharges; Pulse inverters; Temperature dependence;
Conference_Titel :
Electrical Insulation and Dielectric Phenomena, 1995. Annual Report., Conference on
Conference_Location :
Virginia Beach, VA
Print_ISBN :
0-7803-2931-7
DOI :
10.1109/CEIDP.1995.483711