[Prev][Next][Index][Thread]

Re: H.V. Transformers

Subject:   Re: H.V. Transformers
  Date:    Wed, 7 May 1997 20:57:58 -0500
  From:   "Robert W. Stephens" <rwstephens-at-headwaters-dot-com>
    To:    Tesla List <tesla-at-pupman-dot-com>


> Date:          Mon, 05 May 1997 23:49:56 -0500
> To:            tesla-at-poodle.pupman-dot-com
> Subject:       H.V. Transformers
> From:          Tesla List <tesla-at-pupman-dot-com>

> Subject:  H.V. Transformers
>   Date:   Mon, 5 May 1997 12:48:57 +0500
>   From:   "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
>     To:   Tesla List <tesla-at-pupman-dot-com>
> 
> 
> Greetings all
> 
> I have noticed many of you have difficulty finding Neon sign 
> transformers for your Tesla Coils, but aside from Neon sign 
> transformers, Neon sign bombarder transformers and pole pigs
> there is another usually neglected source of H.V. transformers
> namely oil burner ignition transformers. These transformers put
> out typically 10,000 volts at 23 ma. and they are damn near 
> indestructible. They can easily be connected in parallel for higher 
> power levels. Whats nicer yet is most oil burner repair men will 
> throw out the entire burner with the ignition transformer. Right now 
> is the end of the heating season for North America and I have pulled 
> six of these little beauties out of the trash in the past two weeks. 
> When you see an oil burner unit in the trash the transformer is the 
> box on top of the motor typically 5" X 3" X 4" high. Usually the 
> transformers are covered with soot and grease but you can submerge
> these babies in a hot T.S.P solution scrub and rinse, LET DRY BEFORE
> testing. BTW if anyone know of any other untapped sources of H.V. 
> transformers why not share the info with the group.
> 

I am suprised to hear you say that furnace ignition transformers are 
virtually indestrictible.  You must not be plugging your's in.  I 
have found them to be very intolerant of Tesla coil type service, 
somewhat moreso than the generally beefier and notoriously fragile
neons. 

Try an experiment.  Put a 500 pF doorknob cap from each terminal of 
your 23 mA, 10 kV ignition xfmer to case ground and plug it in.  In 
less than 60 seconds you will hear frying/boiling inside and will 
probably have also within this short time have a shorted secondary.

The following scene played to the tune of sizzling sound in 
background....

"This is your furnace transformer, this is your furnace transformer 
with RF bypass caps...any questions?"

Merely 500 pF starts to send these into 60 HZ resonant rise but I 
haven't measured how much.  The same caps tested today on a common 15-at-30 
neon produced a 500 volt secondary voltage rise above the nominal 8000
volts
measured on each leg.

I once parallelled 6 of these ignition transformers to get ~ 1+ kVA the 
hard way for a very early coil.  You are correct, these are an 
alternative source for builders of small coils to neons, but they are 
rather electrically fragile.  They also are not as easy to bolt down 
mounting wise as neons.

rwstephens