Re: Current peak from MMC

To: tesla-at-pupman-dot-com
Subject: Re: Current peak from MMC
From: Finn Hammer <f-hammer-at-post5.tele.dk> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Tue, 13 Apr 1999 16:47:01 -0600
Approved: twf-at-verinet-dot-com

Tesla List skrev:
> 
> Original Poster: "Marco Denicolai" <Marco.Denicolai-at-tellabs.fi>
> 
> Hi Finn.
> 
> If you look at the MKP 375 characteristics, don't forget to have a look
to the
> CAPACITANCE:
> 
> a MKP 375 rated for 2 kV has got 30000 V/us  dV/dT but only in models up to
> 2700
> pF (yes, pF!). Models up to 0.01 uF have got dV/dT = 10000 V/us and models
> up to
> 0.022 uF drop down to 6700 V/us.

Marco, I don`t know where you get your numbers from, but if you read my
post carefully, you will see, that the dU/dT values change, according in
fact with the envelope size of the cap.
In the specksheets that I downloaded from Philips, the 375 is rated at
3300 V/猶 for the big envelope with 27 mm Pitch, and 5000V/猶 for the
envelope with 22,5 mm pitch.


> 
> The MMKP 376 (which is MY CHOICE)  rated for 2kV is available with all
> values up
> to 0.033 uF and for ALL values Philips ensures a dV/dT > 10000 V/us.



Oh! the lovely 376, I was only put off by the pricing in the Farnell
catalogue. But yesterday I called Philips, and asked them to suggest a
wholesaler, so that I could get a better price, and BINGO: They sell
376鋊 at the same price as the 375 : 0,022湩 -at-1600 V for 1/2 dollar, so
I ordered 600 of them, along with 600 VR37 resistors 33 Mohm for a cap:
0.033湩 -at-32000VDc in 30 strings of 20 caps offering a total peak current
ability of 6600 Amps and 6.6 Joule per Bang if charged to 20kV from my
porkchop transformer.

I guess I`d better start gluing PCB sheets together for a rotary disk.
Already got a nice Siemens 3-phase permanent magnet sync. motor for that
gap......

SNIP

Cheers, Finn