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RE: (Fwd) bleeder resistors used with MMC



Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

I think it's important to add that the purpose of the resistors has
nothing to do with equalizing the voltage division across the caps.  The
voltage will divide strictly according to the inverse-ratios of each
capacitor's uF-value to the other capacitors.  To be effective at
ensuring equal voltage division should the cap values be unequal, the
resistor values would have to be much, much lower, incurring
out-of-the-question losses.  The purpose of the resistors as we use them
is strictly to ensure zero residual charge on each cap a reasonable time
(couple seconds) after power is turned off.

Regards, Gary Lau
MA, USA

> Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>
>
>
> I have been using DigiKey # 4.7MH-ND.  I put two in series to help
> get enough lead length to go around the cap.
>
> http://drsstc.com/~sisg/files/BigSISGCoil/MMCpics/Inside-0.JPG
>
> So each cap has two 4.7M ohm 1/2 watt resistors in series.  The RC
> time constant is 9.4e6 x 150e-9 = 1.4 seconds
>
> Cheers,
>
> Terry


> At 12:12 PM 11/2/2006, you wrote:
>
> >Terry,
> >
> >I've spent a lot of time surching the List archives and so far have
> >not found an answer to my question.  What would you recommend
> >as the best size (in megohms I would presume), and wattage level
> >to use with an MMC stack?  I just bought 12 of the CD-942's and
> >will be using all of them in series for a final cap rating of .012
mfd.
> >
> >I know many folks have used resistors to equalize the voltage
> >distribution in these series strings.  Unfortuantely, I never saved
> >any of those posts to the List.  Any help or advice you can give
> >will be greatly appreciated.
> >
> >Best regards,
> >Bill Wysock.
>