Actually, the filament transformers are likely the best ones for voltage insulation.
Many of them are used in 400 to 600v power supplies.
The 5V winding is specifically that high for just that.

I'm buying three buck/boost transformers to ease back my output from the 220 Wye
to Delta.

But I'm buying real buck/boost units.

Martin Eastburn
@ home at Lions' Lair with our computer lionslair at consolidated dot net
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder



Bruce L. Bergman wrote:
On Sun, 02 Oct 2005 22:45:15 GMT, "Leo Lichtman"
wrote:

"AL" wrote:


You need a buck boost transformer. A new one
will set you back $100-$150. (clip)

^^^^^^^^^^^^^^^
Maybe you could find a 32 volt transformer with sufficient current rating,
and hook the secondary up to buck line voltage.


Nice idea, but no.

When you hook a transformer up as Buck-Boost you have full primary
line voltage to ground on the secondary windings, so the transformer
you use has to be designed for it. A lot of the surplus transformers
you find are rated B-B, but the nameplate has to be readable, and you
have to dig out the spec sheets and check first.

The cheaper filament transformers that aren't rated for B-B service
will not have the proper insulation on the secondary windings for that
use, and much excitement can happen - think "Fourth Of July Finale".

It might happen the first time you plug it in, or it can wait till
after a few switching transients puncture the insulation. And best of
all it can easily turn into a fire, if you aren't standing there with
a fire extinguisher close at hand...

-- Bruce --


----== Posted via Newsfeeds.Com - Unlimited-Uncensored-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----