Re: Protection circuit

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "J. B. Weazle McCreath by way of Terry Fritz <twftesla-at-uswest-dot-net>" <weazle-at-hurontel.on.ca>


At 07:23 AM 27/02/01 -0700, you wrote:
>
>Original poster: "Tim by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<warpath-at-wtp-dot-net>
>
>Hi All, I have two NST's which are 15/30's at 450VA. I want to hook them
>in series to get 15/60 to produce 900 VA.  Terry's schematic says that
>it is good at up to 240MA.  Is this enough protection for my setup?
>Thanks to all for your help. Later, Tim
>

Hi Tim,

You should have plenty of protection with Terry's circuit.  I don't know
if you meant to type parallel, but instead typed series, but you want to
put the two NSTs in PARALLEL to increase the current while keeping the
voltage the same as one.  You will need to phase the two transformers in
order to get things to work right.

Join the two transformer cases together with a bare wire and ground it,
then wire the two primary windings in parallel.  Put a piece of high
voltage lead onto any of the four secondary terminals and attach the
other end of the wire to a long insulated handle.  Apply power to the
transformers and bring the end of the wire on the insulated handle up
close to one of the secondary terminals of the transformer that is NOT
connected to the wire.  In one instance you'll get a good long arc,
while in the other you should get no arc and can actually touch the
wire to the terminal.  If you find that you can hook the two left hand
secondary terminals together, you've got it right the first time, if not
then remove power and flip the two primary wires of only one transformer
and try again.  Once you've found which way is right, mark the two left
hand secondary terminals with a piece of colored tape and also put a 
piece of tape on either pair of primary leads that are joined.


73, Weazle, VE3EAR/VE3WZL

Listening: 147.030+ and 442.075+
E-mail:    weazle-at-hurontel.on.ca
           or ve3ear-at-rac.ca
Web site:  www.hurontel.on.ca/~weazle