RE: The MMC debate continues . . . . . .

["Tesla list" <tesla@xxxxxxxxxx>]

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

No, the resistors used on MMC's play NO part in equalizing the voltage
division.  This seems to be a common misconception.

If the applied power was DC and the caps were never discharged (as in a
DC filter application), resistors would establish the voltage division.
But as the applied power to an MMC is AC, the impedance of the
capacitance is many, many times lower than the resistors, so the voltage
will divide according to the ratios of capacitance.

Assuming a .15uF cap being charged with a 60 Hz power supply:
Zc = 1/(2pi*F*C) = 17.7KOhm
Zr (typical) = 10MegOhms

Regards, Gary Lau
MA, USA

> Original poster: "M G" <gt4awd@xxxxxxxxx>
>
>
> The resistors do more than discharge the capacitors after use.
> Resistors across the capacitors help to evenly distrubute the
> electricity across each capacitor. In a MMC setup where the
> capacitors are rated below the voltage that is used the resistors
> would help to prevent any capacitor failures from overvoltage. A MMC
> setup using capacitors rated above the used voltage would see no
> benefit other than safe discharging after use.
>
>
>
> Matt G.