The calculation of equalizer currents in a 4.1 MW lap wound DC machine using finite element analysis
- Univ. of the Witwatersrand (South Africa)
The design of equalizer windings for large lap wound d.c. machines is generally of an empirical nature. This paper presents an analytical technique, using finite element analysis, for the calculation of equalizer currents in lap windings. Each path in a simplex lap winding is influenced by a different pair of poles. It is practically impossible to make the fluxes of all poles identical in large d.c. machines. The result of uneven pole strength is that the voltages induced in the parallel paths are unequal. Since the paths are in parallel, circulating currents flow in the winding; when the machine is loaded the tendency will be to overload certain of the brushes. To mitigate this effect, permanent equalizer connections are usually made to the back of the winding to join points whose e.m.f should at every instant be the same. The circulating currents then superimpose a partially corrected magnetic field. Since equalizer currents cannot be easily measured during operation, this investigation was undertaken to see how finite element analysis could be used to determine the equalizer current sensitivity to changes in the structure. The analytical technique was used to determine the equalizer currents in a large lap wound d.c. generator. The machine modeled has been rebuilt after a major breakdown when problems occurred with equalizer windings burning out.
- OSTI ID:
- 419559
- Report Number(s):
- CONF-9510203-; TRN: IM9706%%103
- Resource Relation:
- Conference: IEEE/Industrial Application Society conference, Orlando, FL (United States), 8-12 Oct 1995; Other Information: PBD: 1995; Related Information: Is Part Of Conference record of the 1995 IEEE Industry Applications Society, thirtieth IAS annual meeting. Volume 1; PB: 977 p.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mechanical States in Wound Heterogeneous Tapes by the Finite Element Method
Single phase four pole/six pole motor