RE: Three phase rectifiers

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Gavin Hubbard by way of Terry Fritz <twftesla-at-uswest-dot-net>" <ghub005-at-xtra.co.nz>

David and Bob

You can get around the power balancing problem by connecting an interphase
transformer between the two rectifier bridges to insure proper current
balance. 

A good industrial electronics textbook should have the information you need.

Gavin Hubbard



Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<sccr4us-at-erols-dot-com>

Bob
Just several cautionary notes...

The "Delta" connected transformers (3) will have a turns ratio 1.732 times
higher on the secondary winding then the "Wye" connected transformers.
The reason for this is the Delta-Wye transformation to keep the two
transformers balanced kVA load wise. Any other ratio and you may get
destructive bucking (can you say "Let's let the magic smoke out of our
diodes!!! "   :^)    )

Also, be aware that the kVA to DC kW conversion factor with a 12 pulse
rectifier is considerably less then 0.6 (ie you need about 1.6kVA 3 ph
for each 1.0kW DC output).  I speak this from experience, having to build
a very high power low voltage linear regulated power supply (4kW to load
at 22V) for a separate R&D group...

Cheers, and regards!
Dave Sharpe, TCBOR
Chesterfield, VA. USA