Re: Short circuit

Subject:       Re: Short circuit
       Date:   Thu, 05 Jun 1997 23:34:21 -0700
       From:   Bert Hickman <bert.hickman-at-aquila-dot-com>
Organization:  Stoneridge Engineering
         To:   Tesla List <tesla-at-pupman-dot-com>
 References:   1

Tesla List wrote:
> Subject:  Short circuit
>   Date:  Thu, 5 Jun 1997 18:09:23 -0700 (PDT)
>   From:  gweaver <gweaver-at-earthlink-dot-net>
>     To: Tesla-at-pupman-dot-com
> While running my 1350 watt Tesla Coil today something very strange
> happened.
> The ON/OFF switch shorted itself closed and I could not turn the Tesla
> Coil
> off. I tried the switch several times and it refused to turn off.  I
> then
> walked a few steps to unplug the cord from the wall when it suddenly
> arced
> on the side of the cord about 2" from the plug.  The arc turned into a
> hissing ball of fire.  For several seconds the Tesla Coil was still
> making
> sparks and the extension cord was arcing also.  I unplugged the cord and
> found the copper wires were melted and burned in half on the cord.  I
> know
> high voltage can do strange things but never had this happen before.  If
> only the switch had gone bad or only the cord had fried I would guess it
> died of old age.  But 2 things fried within seconds of each other makes
> me
> think it was caused by something.  Has anyone ever had something like
> this
> happen?
> Gary Weaver


What are you using for a ground on the base of your coil? What is the
green earthed wire in your line cord tied to in your system? Some
coilers have used the line "earth" connection for a ground on smaller
systems. This elevates the potential on this wire from several hundred
volts to a kilovolt or more. If you then get a flashover to the
power-line hot or neutral, the resulting 60 hz power arc can do nasty
things (like welding switch contacts, melting blower motor wires, or
blowing out other electronic equipment tied to the mains... :^[}. Your
experience shows why an emergecny "kill" switch using a power contactor
is a very good idea!

Safe coilin' to you!

-- Bert --