Re: Earth leakage and SS Variac

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

Original poster: "Byron by way of Terry Fritz <twftesla-at-qwest-dot-net>" <byron-at-4zzzfm-dot-org.au>

On Sat, 1 Sep 2001, Tesla list wrote:

Up to now, prior to starting ti play with NSTs and ignision coils, I
normaly play with low voltage stuff.
However, due to my ability to make stupid mistakes while running things
and being a little clumsy, I'm trying to put in a few more safty levels
than normal. I know they aren't garenteed to work, but circuit breakers
and earth leakage will add a little more, if they save me once, it's good
enough for me. :)

As far as safty on the purely on/off stage, I /WILL/ make sure the box is
switched off(It's designed sofar to be rather hard to start, needing two
hands for 5 seconds, a keyswith and no faults), w/ big red, flashing lighs
for 'coil on' and green for coil off. The lights themselvs have fault
detection(Atleast the green and red main ones, and will prevent the box
from powering up). For full power to be applied any other way, is asking
for two(maybe three) main and interlock power relays to fail, and the
supply breajers too.

There's a deadman's switch that will be enabled s few seconds after the
coil switches on, that failing will again cause shutdown.

The cable idea, while very good, will be prone to me forgetting about it,
big flashing lighs tend to work a lot better with big red buttons that
kill everthing. It's ment to be hard to turn on, so easy to turn off.

The only problem with ELDs is will the coil's normal operations false
trigger them, or do I need to put some kind of RC(As RLC seems very bad
acording to everyone) to cut out most of the rubbish?

(If there was some way to ELD detect, using the balanced core(?) method
onthe 15kV side, would it trip out if the streamers hit the primary coil?
Just a thought)

The final layer of protection, will be my roomate nearby ready to pull
cables or press the big button. 

> 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
> 
> 
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