shocks from unpowered secondary?

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

Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>" <davep-at-quik-dot-com>

Tesla list wrote:

> Original poster: "David Kyle by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <dave-at-kyleusa-dot-com>

> Well my shoes were fairly sensible but I would not classify them as
> shock proof. I seriously doubt that I had accumulated a charge as only
> moments before I had my hand on the grounded Variac case. I suspect as
> others have suggested the charge must accumulate on the form or coil
> coating. My coil is coated with very thick polyurethane.

	Possible.  Not clear how effectively it would couple from
	the form to the _toroid_.  But, if it happens...
 
> Next time I run it I will try a few unpowered experiments to see if I
> can learn any more about it. The shock really startled me since it was
> totally unexpected. I am very lucky I did not cause the toroid to fall.

	such shocks are quasi one time event's, hard to instrument.
	That Said. might be interesting to fab an electroscope
	(coupla bits of Al foil, on a paper clip, inside a
	jar, etc...).  Assuming a Hi Z DC DVM is to hand, simply
	'grounding' one lead, then moving the other towards the
	toroid (and form, etc) might be instructive.

	(One might test by doing the same to the front glass of
	a TV tube.  Or 'puter monitor...  (with them on...
	then off...))
 
	This will NOT yield a measured value, but should
	allow the field to be sensed....

	(I actually did the meter trick the first time, accidentally
	with a moving coil meter.  NOT recommending drawing an
	arc/spark TO the meter probe...)

	Just some rambling...

	best
	dwp
> =========================================
> Dave Kyle
> Austin, TX USA
> Email: dave-at-kyleusa-dot-com
> 
> -----Original Message-----
> From: Tesla list [mailto:tesla-at-pupman-dot-com]
> Sent: Tuesday, February 19, 2002 1:34 PM
> To: tesla-at-pupman-dot-com
> Subject: RE: NON-static shocks from unpowered secondary?
> 
> Original poster: "Malcolm Watts by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> Hi David,
> 
> On 19 Feb 2002, at 8:09, Tesla list wrote:
> 
> > Original poster: "David Kyle by way of Terry Fritz
> <twftesla-at-qwest-dot-net>"
> <dave-at-kyleusa-dot-com>
> >
> > I drew a quarter inch static spark off the toroid after the coil hand
> > been powered down for several minutes (all AC connections severed). It
> > really surprised me as the base of the secondary was still connected
> > very solidly to earth ground so I had assumed and residual charge with
> > have drained away. I now routinely discharge the toroid prior to
> > touching it.