Re: 811A first light

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

Original poster: "Brent Turner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bturner-at-apc-dot-net>

Hi -

Having built a VTTC myself (pair of 805's), I used a MOT from an
industrial oven. Had two 1100 volt windings in series which paralleled
quite nicely for 500mA output. Drives my 805's directly with no current
limiting.

You shouldn't need current limiting in the transformer anyway. The
grid-leak bias (variable resistor across a capacitor, whole thing in
series with the grid) establishes not only a slight phase delay, but
also limits the plate current.) is adjusted so that plate current falls
within the tube's plate spec's. The tubes are not driven into full
class-C operation in the classic VTTC circuit.

- brent



Tesla list wrote:
> 
> Original poster: "Dr. John Gudenas by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <comsciprof-at-ameritech-dot-net>
> 
> James
> The 811A can only handle 175 mA on the plate -at- around 1500 volts. If you use
> a MOT with out any current limiting device you will likely melt the plate.
> Check out my triple 811A coil on:
> www.scifair-dot-org/hvdata
> 
> John W. G.
> 
> John W. Gudenas, Ph.D.
> Department Chair of Computational and Natural Science
> Aurora University