To: mail11:;-at-cimcad.enet.dec-dot-com (-at-teslatech)
From: I am the NRA <pierson-at-cimcad.enet.dec-dot-com>
Date: Mon, 28 Nov 94 11:52:15 EST
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>> All transformers are not created equal. Neon Sign transfromers and
>> Oil Burner ignition transformers are designed for arc/spark duty
>> (quasi short circuit).
>> Microwave oven transformers are not.
>I know that neon sign xformers are buit with a magnetic shunt to limit
>the current during a short-circuit condition and that microwave oven
>xformers aren't, but what other differences are there and how would
>they affect their use in Tesla coil circuits?
That is what i waas discussing, the current limit effect in the
sign/oil burner transformers. Those two are designed ot handle an arc
or spark load. The Oven transformers are not.
>I wired two 4kV microwave oven xformers in series to give 8kV out, and
>(if my meter was correct) I was pulling over 60 A from the wall (on a 20
Methinks something was not happening as expected. 60 (real) amps
(or 60 out of phase amps) would trip the breaker REAL QUICK.
>when I was drawing an arc! Obviously, to use a microwave oven xformer you need
>external current limiting (like the larger pole and potential xformers),
Yup. Only to some folk it may not be obvious. Adding this will affect
simplicity and efficiency.
>and you can saturate the core and heat things up if you try to draw too much
>current, but I assumed they would work fine if you limit the current and
>don't drive them too hard?
I should think so. That was teh gotcha i was worried about.
>A few issues ago, the TCBA newsletter featured a design where the builder
>rectified the output of a couple of microwave oven xformers for a DC powered
>Tesla coil and was getting great results judging from the pictures and
What was used for current limit?
(An "rf choke" to "keep the RF out of the transformer" might, by
accident or design serve the function....)