Re: Bleeders for a cap bank

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

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


At 04:51 PM 7/7/2001 +0100, you wrote:
>Hi all
>
>I have a pretty standard MMC setup with 10meg bleeders across each cap -
>what kind of time do the resistros take to bleed the caps? This is my
>logic...
>
>1 farad=96000 coulombs
>0.068uF = 0.000068F
>0.000068*96000 = 6.528C
>
>at 714.3V per cap, and I=V/R, 714.3/10,000,000 = 0.00007143A thru each
>resistor.
>
>so, since Q=IT and therefore T=Q/I then T=6.528/0.00007143 = 80 thousand
>seconds.
>
>which is obviously wrong.... so how long do the resistors take to bleed the
>caps?
>
>Thanks,
>Jason
>
>Geek # 1139 Rank G-1
>www.thegeekgroup-dot-org
>
>