At 23 January 2003, 04:49 PM, Joseph B. Reid wrote:
In 3-phase the phases are separated by 120� between each pair of phases. With 3 phases it is easy to produce a rotating magnetic field in an induction motor which does not require brushes. 3-phase may have other advantages, but I am not an electrical engineer.Joe is probably correct with respect to general electrical power distribution: it is pretty much universally 3-phase (or, for VERY high power distribution, direct current (DC) for which "phase" has no meaning).
There are no 4-phase systems.
However, 4-, 5 and 6-phase systems exist in certain applications:
four-phase: see attached PDF (one of six pages -- ask if you want the rest of it)
neat illustration of 1, 2, 3 and 4-phase motors: http://www.fleadh.co.uk/srm.htm
Jim Elwell, CAMS
Electrical Engineer
Industrial manufacturing manager
Salt Lake City, Utah, USA
www.qsicorp.com
2001APR19.pdf
Description: Adobe PDF document
