19 Oct
2007
19 Oct
'07
11:55 a.m.
On Friday 19 October 2007, Chuck Guzis wrote:
On 19 Oct 2007 at 13:33, William Donzelli wrote:
Or, of course, you could just find a big heavy single phase motor, and
pair it up with a 3phase motor of the same RPM rating with a
shaft-coupler, and make your own single-to-three phase MG set.
Pat
--
Purdue University Research Computing --- http://www.rcac.purdue.edu/
The Computer Refuge --- http://computer-refuge.org
With older gear, why not? Most of that classic
mainframe stuff has
brute force power supplies, often fed by voltage regulating
transformers (almost always a Sola, it seems).
The three phase motors in the drives will just help things along,
as well.
My experience with these things (admittedly only with machine tools)
shows a strong tendency for less-than-perfect (i.e. 120 degree)
phase- to-phase relationships and fairly drastic phase-to-phase
voltage and current variations. They work with motors, but none
allows for full motor nameplate loading (usually around 80 percent of
nameplate). My take is that they work "sort of". Heaven only knows
how a power supply would behave attached to one of these things.
My feeling is that if you have to power some three-phase big iron
from a single-phase source, it's probably better to take a look at
one of the modern (and expensive) solid-state converters--or get some
real three-phase distribution installed.