RE: Wire-wound resistors as dummy test load

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-hp-dot-com>

I don't have an answer to the variation in inductance (does seem odd) but I
question the utility of dummy-loading just the power supply.  The load
presented by a tank cap being discharged by a gap bears no resemblance to a
resistive load.  A power supply loaded with resistors probably won't need
any power factor correction, while the "normal" configuration will be quite
another story.

Further, an 800 Ohm, 800 Watt load is only suitable for an 800V power
supply, much too low for TC use.  W=V*V/R.

Regards, Gary Lau
MA, USA


>Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<Mddeming-at-aol-dot-com>
>
>I found 4 200-Ohm, 200-Watt wire wound resistors all the same brand, that I
>thought I would string together as an 800 Ohm, 800 Watt, test load for my TC
>power supply, while checking things such as PFC cap size, etc.  However,
when I
>checked them with my meters, I got these readings:
>
>1) 205 Ohms 339 uHy 
>2) 206 Ohms 221 uHy 
>3) 210 Ohms 225 uHy 
>4) 208 Ohms 508 uHy 
>
>Physically, they all seem to be the same size, shape, and construction,
but the
>variation in inductance seems unreasonable. Has anyone looked into the
>inductance of wire-wound resistors before? If so, is this reasonable? I know
>that at 60 Hz, this only amounts to about 0.1 to 0.2 Ohms inductive reactance,
>but it seems strange.
>TIA,
>Matt D.