Re: MMC from Microwave Caps

["Tesla list" <tesla-at-xxxxxxxxxx>]

Original poster: Terry Fritz <twftesla-at-uswest-dot-net>

Hi Alan,

	You have listed the potential problems.  However, if you want to actually
try it, it would be interesting just to really see for sure what happens.  

Cheers,

	Terry

At 09:50 PM 11/30/2000 +1300, you wrote:
>Hi All,
>
>I had an idea for a cheap 'MMC' using microwave capacitors.
>
>The capacitors are 1 uF, (1 E -6 Farads)
>If I put 20 caps in series, (one string)
>the voltage rating would be a whopping 40 kV *RMS* or 56 kV DC!!
>(Assuming the faceplate voltage of 2000 VAC)
>
>The capacitance would be 50 nF (0.05 uF)
>
>At first glance, this seems like a great MMC, but there are a couple of
>problems I have
>thought of.
>1) I remember someone telling the list that these caps have small internal
>leads and thin
>      plates, perhaps limiting their current discharging capability
>2) Their dv/dt (Volts per microsecond) may not be high enough for TC use
>3) Due to tolerances, the voltage stress on each cap may be unequal, leading
>to early failure.
>    (although the voltage rating of the whole cap is very high)
>4) One string of caps may not be able to handle the current stresses
>
>I have 23 microwave capacitors.
>I'd really like to be able to do this, (as it's free,) and I'm desperate for
>a cap for first light
>so I can spend some time thinking about what I want to buy for a more
>traditional MMC,
>as it will cost me quite a lot of money (for a student).
>
>*Does anyone know of any problems with this idea, or can confirm my
>thoughts?*
>I don't care if the caps die in a few hours, I got them free.
>
>Thank you very much,
>
>Alan Williams
>
>