Re: It Just Stopped

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

Original poster: "Bert Hickman" <bert.hickman-at-aquila-dot-net> 

Hi Matt,

My guess would be that the Maxwell cap is failing as a short circuit but 
only when you apply high voltage, but at low voltages it still measures OK. 
Try replacing it.

-- Bert --

Tesla list wrote:
>Original poster: Mddeming-at-aol-dot-com
>Hi All,
>     Something happened last night that has me puzzled. I was testing 
> 4.25" coil. It had been run intermittently for about 1/2 hour. I fastened 
> a pointed rod to the center bolt of the topload (dual toroids) pointing 
> upward, preparatory to making a "pinwheel". I was getting nice 3ft+ arcs 
> to the ceiling of the lab, (coil is caged 10' x 9' x 8'.) After about a 
> minute, it suddenly went dead. No arcs, no gap spark, no sound except the 
> vacuum on the sucker gap. It had been drawing ~18 Amps on 30 Amp circuit 
> prior to problem. Indicator lights showed power reaching primaries of 
> NSTs. Variac output showed 120V. No racing sparks noted, no arcing to 
> primary. I shut system down, waited ten minutes, tried to restart... Nada!
>     I disassembled everything and checked each component:
>Xfmr 1 Allanson 15/60:  6000v left and 5990v right to ground terminal with 
>102V input. (My HV meter limit is 6 kV)
>Xfmr 2 Transco 15/60: 5995v left and 5980v right to ground terminal with 
>101.8v input.
>Tank cap: Maxwell 37xxx series, 30 nF nominal,. measured 29.95nF with 
>RdShk DMM and 30.91 on AADE L/C II-B. On the 14th of July, it measured 
>31.07nF on the L/C II-B when air Temp was 11F warmer and Humidity was 30% 
>higher.
>Sucker Gap 1 HP vacuum spaced 7.5 mm.
>Safety Gap spaced 5 mm Left and 4 mm Right.
>     Reassembled everything and... Nada!!
>Any Guesses??
>Matt D.
>
>.