Transformers in the UK

 * Carbons Sent to: usa-tesla-at-usa-dot-net

Quoting <i_hopley-at-wintermute.co.uk> (Ian Hopley):

> My two transformers give me about 1.1KVA after unpotting and 
> removal of a couple of shunt plates, and are probably more than
> ample for my first attempts, although i'll probably soon 
> outgrow and/or destroy them in my first efforts.  


> This has led me to look at alternatives and have considered 
> microwave units as a bit of a safty liability, lower power 
> option. 

In Volume 14, #3 (July-Sept 1995) of the Tesla Coil Builder
Association publication _NEWS_ there is an excellent article
on placing four microwave transformers with the primaries in
parallel and the secondaries in series (hot coring the end two
units) to produce a workable power supply.

Last night my good coiling buddy Dave Hartwick calls me and asks
if his 11.5 kV 300 mA microwave power supply would be of interest
to anybody... Anybody?

Dave has been making some really simple modifications to these
transformers and is coming up with solid HV power supplies for
Tesla coils. He indicated by phone that on 9 out of 10 microwave
transformers he has worked with, the grounded lead wire from the
secondary can be freed from the core with minimal effort. The
freed up wire is then soldered to an extension lead, the
connection is insulated with a section of heat shrink tubing.
Epoxy, hot glue, or polyester resin is used to beef up the
insulation between the core and the two windings.

He then places six units with the secondaries in series to obtain
the required voltage rating without hot coring.

He admits that there is a possibility of breakdown with the
possibility of the HV getting back to the LV mains; so he uses
inductive current limiting and an isolation transformer with
grounded core for safety. 

Dave is giving up this line of experimentation soon because he
has a new pole pig on it's way, but I have implored him to write
a paper on this for publication (he has only a 286 with no modem
and a 5-1/4 floppy drive, I have also begged him to upgrade
systems and join us...)

I hope this sparks as much interest as I feel it is worth,
especially to you guys in the UK.

Richard Quick 
... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12