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From: rpm@wd.msc.umn.edu (Rod Meyer)
Newsgroups: sci.electronics
Subject: Toroidal Transformers
Keywords: Toroids transformers
Message-ID: <2167@uc.msc.umn.edu>
Date: 18 Jul 90 21:41:43 GMT
Sender: news@uc.msc.umn.edu
Reply-To: rpm@wd.msc.umn.edu (Rod Meyer)
Organization: Minnesota Supercomputer Center
Lines: 36

Hello.
I need some help from somebody who understands transformers
very well and specifically toroidal transformers.  Please
e-mail me if you have a good knowledge.


Specific problem:
I enjoy racing RC cars but do not enjoy waiting for the batteries
to charge back up.  I have been looking at building a battery charger
that will be capable of charging many batteries at once.  The major
obstical that I need to overcome is finding a suitable transformer
that is capable of putting out 20 amps.  (You may have seen my
request about a month ago looking for power supplies.)  Anyway, I
recieved very little responce from the request (2 messages).  One
responce was very good.  He told me to look at a company called "Amecon"
in Anahein, California.  They make toroidal transformers for various
reasons.  When I talked to one of the engineers about the transformer
he instructed me that it would not be a good idea to use a toroid
because they tend to saturate under non-linear and/or capacative loads.

My question:  Why?  I don't understand why a capacative load such as
a battery would cause the transformer to saturate.  Another interesting
question if you can help me.  Can I get around the saturation problem
be using a bigger toroid?  I figure the most I will be drawing will be
around 20 amps, probably less.  They make a toroid rated for 20.8 amps
and I was going to use that one.  They also make one rated for 33.4 amps.
If I use the bigger toroid and keep the amperage much lower than what it
is rated for, will I avoid the saturation problem?  What happens to the
toroid when it becomes saturated and it there a way of detecting this?

Any help would be greatly appreciated.  If the problem is too complex
for a written message, send me a phone number and good times to reach
you and I will call you.

Thank you.
-Rod