Re: [CAD_CAM_EDM_DRO] transformer selection

In a message dated 3/21/2004 10:06:06 PM Central Standard Time,
sspeed@... writes:
I have found a 220 volt pri to 120 sec volt transformer 25amp 3kva rated
Is this over kill? or is it too small?
If the PRICE is right, NO, not overkill. But, were you designing from
scratch, I'd say yes.

No, certainly NOT too small! In fact, you may find that the output voltage
WILL be a bit higher than you expect, as the 25 A. secondary will be so lightly
loaded with just the 10 amp you need.

As you say "220 volt pri". MOST single-phase AC in 21st C. USA is 120/240.
The days of "110/220" are mostly gone, with possible exceptions in very
"way-out, rural" sites, or parts of some still-19th C. towns in the far-N.E., etc.
Thus, if you put a REALLY-220 VAC-pri. transformer on a 240 VAC supply, the
output will be more like 130 VAC, rather than 120, IF loaded to 25 A. If only
loaded to 10 A, you might be seeing 140 VAC! Gotta WATCH such subtleties!
Jan Rowland, old troll


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