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Re: Self-built power transformer



Doug,
	How much power are you going to draw from this transformer and are you going
to use it for a tesla coil?  I have built my own 29 kV 300 ma transformer and
it has worked fine with my tesla coil.  You said 15" long and 1" diameter.
This implies to me that you are using a cylinder core.  The losses from this
wouldn't even be funny.  You need to use either a torriod or a double E core
which looks like a 8 on its side.  If you used your 40 primary turns and 1600
secondary turns you would have a 1:40 transformer.  So with an input voltage
of 120 volts you would get 4800 volts.  With those wire sizes you are using
you wont be able to pass much current through the transformer without
something melting.  Form my calculations I get about 0.81 volts / (turns *
inch ^ 2) for the maximum flux in a transformer before saturation.  This value
does leave some room for error.  Let me give an example.

Using a torriod with a 5" radius and a 0.5" radius of curvature you get Pi
inch^2 of cross sectional area of the core.  Now if you want to connect the
primary to 120 volts you will need 120 / (0.81 * Pi) turns or about 47 turns.
Now if you wanted 12000 volts form the secondary you would need (47 * 12000) /
120 secondary turns or about 4700 turns.

I hope this helps a little.

For information about my transformer go to
http://members.aol-dot-com/tesla00/o_index.htm

Erik Schulz

>> I'm currently building a power transformer for my coil, and I'd like to
>> get some reactions on it. It's wound on a 15" long, 1" diameter
>> commercial iron core with 1600 turns of 32 AWG magnet wire for the
>> secondary, and 5 windings, 8 turns each, of 24 AWG (they're on top of
>> each other) for the primary. I'll probably wind a second primary so I
>> can run it on 240V as well as 120V. The whole thing will be immersed in
>> motor oil. Please reply with your opinion--I want to be sure it won't
>> fry on me when I power it up.