Re: My First Toob Coil

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

Original poster: "Edwin G. Buttell by way of Terry Fritz <twftesla-at-qwest-dot-net>" <edd.b-at-snet-dot-net>

 
> Original poster: "Sundog by way of Terry Fritz

> Hi All!
 
> With many thanks to my buddy James, my first toob
> coil is well underway.
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> My specs so far
 
> Toobs - 2   833a's.These things just look sinister
> when powered up,at a rated 1650 watts each, 
> these should really rock in toob coil duty.

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  Edd.B Writes;

  833 TUBE MAXIMUM RATINGS ( with forced air cooling )

  max plate dissipation 450 watts
  max plate voltage    4000 volts
  max plate current     500 mills
  max grid  current     100 mills
 
  max useable output per tube.

  Class"C" oscillator at 75% efficiency.

  4000 volts X 400 mils=1600 watts input X 75%=1200 watts
  output with 400 watts dissipated as heat. The plate will
  run red/orange hot at this input. Tube life will be rather
  short !!!!! 
 
  At this input level there is NO room for error. If the 
  efficiency drops below 75% the tubes WILL BURN UP very,very
  quickly. 

  I would recommend using a variac in the transformer primary
  circuit to set the plate voltage to a lower,safer, level and
  adding a HV voltmeter and an ammeter (0 to 1 amp) to monitor 
  the input power.

  My 4.5" X 18" coil uses three 833A's in parallel with up to
  3500 on the plates and has a good / impressive sword 
  like output.

  Be advised that tube coils can be very hard to tune 
  correctly and the power in versus display out is
  rather poor when compared to a spark coil with the 
  same power input. Above all.... BE CAREFUL.... at
  power levels you will be working with you cannot make 
  a mistake, it WILL BE the last one you will ever make !!! 

  73's de edd.b
  Storrs, Ct.

  BTW. I am a ham radio operator and I have built
  many high voltage,high power amps over the years.