Re: Gap Losses (II) Re: Primary Heating

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

Original poster: "Malcolm Watts by way of Terry Fritz <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>

HI Dave,
         Let me restate my admittedly ambiguous position on this:

On 12 Mar 2002, at 12:29, Tesla list wrote:

> Original poster: "davep by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<davep-at-quik-dot-com>
> 
> Tesla list wrote (in part):
> 
> > Original poster: "Malcolm Watts by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <m.j.watts-at-massey.ac.nz>
> 
> > > come on people lets give it a thought or 10 ....  just maybe we can come
> > > up with a new approach ...
>  
> > I don't think it's any great secret. Increase Xp to reduce gap
> > current since the loss is essentially a VI function.
> 
> 	Is it?
> 	Seriously...
> 	ARC losses aren't.  (Arcs have a negative resistance
> 	characteristic:  More current means LESS voltage drop.)

Not to a linear degree. Voltage drop is not proportional to current 
rise. The point I was trying to make is that the gap cannot be 
accurately modelled as normal resistor since instantaneous Rgap is 
inversely proportional to Igap, and the degree of proportionality is 
not a straight constant (although for a given situation, the loss can 
be quantified as power lost in an *equivalent resistance*). The fact 
that the gap cannot be modelled as a normal resistance is given away 
by the primary's linear ringdown. Rgap in fact changes on the fly.  

> 	Sparks ARE a different beast, but, I'd have thought
> 	sparks were similar?  (without checking references...)

Try Sargent and Dollinger's "High Power Electronics".
 
> > Interestingly enough, there is probably only so well you can do.
> > Consider that for a given Xp, if you reduce all other primary
> > losses to an absolute minimum, primary current is maximised
> >which = maximised gap losses for that value of Xp. A related
> > approach is to run real high primary voltages as well to make
> > the Vgap drop a smaller fraction of the total.
> 
> > Regards,
> > malcolm
> 
> 	best
> 	dwp

Regards,
malcolm