Re: Earth leakage and SS Variac

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

Original poster: "S & J Young by way of Terry Fritz <twftesla-at-qwest-dot-net>" <youngs-at-konnections-dot-net>

Byron,
The best and safest thing you can do to prevent stupid, life-threatening
mistakes such as electrocution is build stuff where the voltage is never
more than about 20 volts.  The next best is to UNPLUG your power supply so
you visually can verify it is not powered, then discharge anything that can
hold a charge, i.e. tank caps.  Depending on ground fault breakers, switches
and the like is completely NOT safe.  I personally would NOT use them as
they can give a person a false sense of security - best to unplug stuff.
Your control box can have a female power socket and a short male power cord
and plug right on the front panel.  The archives have other safety posts.

Likewise, I would not trust a solid state variac to be off or to stay off -
the triacs or whatever can fail and put out full voltage.  At least a
electromechanical variac in the off position is not likely to suddenly put
out power.

Unplug for safety!
--Steve


----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Friday, August 31, 2001 9:24 PM
Subject: Earth leakage and SS Variac


> Original poster: "Byron by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<byron-at-4zzzfm-dot-org.au>
>
> Hi, I'm new to this, and partway through trying to build a control box
> capable of preventing me from making a few stupid mistakes, like touching
> the primary side..
> The main way I have of doing this is with earth-leakage protection, the
> first beig a normal meter-box type ELD. The second a current detection
> from the centertaped earth the NSTs have. Has anyone played around with
> anything like this? Does the coil's spikes and other crap it puts on the
> lines cause false triggering?
>
> My other idea, was, instead of using a normal variac, wich seems anoying
> hard to find and expensive to buy, if it' a good idea to build a
> solid-state version, the design I currently have involves cutting the
> half-waves of the cycles at a point along the wave.
> (aka: http://www.zetetics-dot-com/bj/papers/phd/appxa.pdf (Second section
> down)
>
> Thoughs apresiated.
>
> (And the coils are cool! I have so been looking forward to building one
> for ages! And I have nearly everything I need! (Once I can convince some
> people that the safty conreols are good enough))
>
>
> --
> __
>   Triple Zed  102.1MHz Agitate, Educate, Organise
>   Brisbane, Australia +61 7 3252 1555 voice
>   byron-at-4zzzfm-dot-org.au +61 7 3252 1950 fax
>   www.4zzzfm-dot-org.au
>
>
>