MMC : dV/dt max

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Original poster: "Samuel Rosset by way of Terry Fritz <twftesla-at-uswest-dot-net>" <samr-at-bluewin.ch>

Hi everyone,

When my WIMA MKP 10 I used for my MMC were destroyed, someone on the list
suggested that I should check the pulse rise time : dV/dt max. It was 250
V/us for the MKP 10 and 3500 V/us for the FKP 1 I plan to use.

But I wanted to know how to calculate this dV/dt max for my MMC. After
manipulating equations, I found that the max pulse rise time was given by :

dV/dt max = (sqrt(C) * Uo) / (n * C' * sqrt(L))

C : Capacitance of the whole MMC [F]
C' : Capacitance of a single cap [F]
n : number of strings of the MMC
Uo : Charged MMC voltage [V]
L : Primary coil's self inductance [H]

which gives me 984 V/us for my MMC, which would explain why it failed

Has anyone tried to calculate this pulse rise time? Did you get the same
result?
For those who are interested and have the time, the detail of the derivation
can be found at :
http://www.chez-dot-com/samr/mmc/mmc.htm

Tell me if this seems right

Thanks in advance

Samuel