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Re: Danger, and I don't understand why.
On Thu, 12 Aug 1999 12:04:15 -0600, you wrote:
>Original Poster: ARSONIST01-at-aol-dot-com
>
>> I
>> turned off the power switch, unplugged the supply cord, walked over
>> to the gap, and pushed the wires apart with a plastic rod. To my
>> surprise a 4mm white spark snapped across the gap.
>
>RIchie, all,
> This occurrence of an NST "holding a charge" is not uncommon. Last week i
>was paralleling two Nsts( a 15/60 and a 15/30). after i successfully
>paralleled them, i tried to hook them up on a jacobs ladder to see the efect
>of a more powerful xfmer on a jacobs ladder. When i first hooked it up and
>turned it on, nothing happenend so i turned it of. Like Richie, i thought
>that once its off, its off and all charges are dropped s ince the nst isn't
>supposed to hold charge. But i was dead wrong. When i touched the rods to re
>position them, i got one hell of a zap from them.
> This little incident wasn't posted to the list becuase i thought this was
>a rare incident since i haven't heard of it before, but now i guess this
>might be a common occurrence, again, I would like to know why this happens.
>Getting shocked in Los Angeles,
>-Alan
>
Could it be the capacitance between the NST windings to the case ? Is
the centre-tap actually grounded to the case ? If not, it's
conceivable that a charge could sit on the windings (which are of
course well insulated) when switched off. This charge would of course
be between windings and ground, not across the windings.