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Re: Questions about current
Original poster: "davep by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davep-at-quik-dot-com>
Tesla list wrote:
> Original poster: "Matt S. by way of Terry Fritz <twftesla-at-uswest-dot-net>"
> I have a couple of questions I was wondering if someone could possibly
> answer for me.
> (I am in the process of launching off my first coil and am hoping to learn
> as much as possible as I go).
> I am fully aware of the basic nature of these questions an appreciate any
> 1. Is there any current 'lost' to corona?
Where in the system?
NST voltages are just getting into the range where Corona is a
major factor. Along the secondary, corona can rob current.
> 2. I understand that an NST is current limited. Is it also a constant
> current kind of thing - i.e. when I'm only putting 80 volts to my 12/60
> NST, is it still supplying 60 ma?
Depends on the exact transformer. They are _quasi_ constant.
What the transformer supplies depends on several things:
Current in (set, usually, by voltage in)
Details of the core (the famous air gap).
Assuming a low enough load current will fall somewhat, but
not (FOR AN NST!!!!) directly as the voltage. At 'really
low voltage' input, current out will be in proportion to
current in. As the current in rises, the current out
will start to limit.
> 3. Is it out of the question to toss an old common analog current
> meter in the output of my NST (before powering it up that is)--
If done with care (and, preferably with an expendable meter
8)>>), its fine. Read the meter from a difference as it
is live. (meters have a relatively low (tho nonzero)
impedance/resistance, so the voltage ACROSS the meter is
minor. I'd stick with nonrectifier (moving iron, etc, etc)
type meters. AND the reading will be nonexact, unless the
load is resistive. Still, it will provide a 'picture'
of what is happening.
> (I'm trying to grasp the nature/% of the voltage drop across the
> internal components of the meter in relation to the nst/gap
> circuit... .......and probably missing some key point).
Should work fine, just recall the meter is live and will
bite. And, if inadvertent short circuit applied, the meter
may be toasted. Recommend an expendable one. Bot cheap at,
say, a ham flea market....