Re: Bleeders for a cap bank

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

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>
> 
> Hi Jason,
> 
> Caps will bleed down to 0.674% of their original voltage in 5xRxC seconds.
> So 0.068uF and 10Meg gives 3.4 seconds.  Which is just right.  Fast enough
> to discharge the caps before you should be touching them but slow enough
> not to bother the coil's operation.
> 
> The equation is:
> 
> Vt = V0 x e^(-t/RxC)
> 
> Where:
> Vt = Voltage at time "t"
> V0 = Initial voltage on cap
> e = Natural log function (2.71828...)
> t = time in seconds
> R = Resistance in ohms
> C = Capacitance in Farads
> 
> Cheers,
> 
>         Terry

	I still worry about deterioration of those resistors due to operating
at much beyond their rated voltage.  Has anyone ever measured any after
a few hours of operation?  In my experience they usually fail open, an
unsafe thing if you're expecting them to discharge the bank.

Ed