On Tue, 8 Aug 2006 15:01:26 -0400, "t.hoehler"
wrote:


"Mark Fortune" wrote in message
.. .
Greetings to the collective.

For my next project I want to build a bench power supply and do away with
this old switch mode AT computer PSU that i'm currently using.

The design I have in mind will be pretty beefy, giving a wide range of
fixed and variable output voltages (i'm thinking from -50v up to +50) and
deliver up to 5amps of current. if my estimates are right i'll need a
600va+ (100v * 5a + overhead) transformer to do the job well. Now i've had
a look at some transformers in this range, and they're a little out of my
price range. so now i'm considering building my own.

The specifications I need are as follows:

primary: 0-230v @ 50Hz
Secondary: 60v-0-60v
secondary output current max: 5A

I have an intermediate understanding of transformers, but have never
actually built one, hence I am seeking advice from those with experience
in this field.
So where do I start? what type of core is best for this application? - I
have a friend who's blasting off that toroids are best, but i'd like a
second opinion, and what kind of wire to use for the primary and
secondaries? what are good safety practices regarding insulation? Is this
even a feasable project to undertake (moreso on the money side than
timewise). Any other advice also greatly appreciated.

regards,
Mark

Not really worth the effort, IMHO. However, take a look at All Electronics,
Hosfelt Electronics, MCM Electronics. There are others also. They have over
run surplus trannys with really good prices. The other alternative is try to
find an old high power am fm receiver which is kaput and not worth fixing.
They have a transformer with the approximate outputs you seek. You're right,
if you have the time, building your own power supply is fun and saves lots
of loot.
regards,
Tom



I had 3 toroids made by Tortran a couple years ago for a homemade
audio amp, they where very reasonable. I recommend you tell them to
give you a non-thermo protected primary.