MMC vs Commercial Caps

• To: tesla-at-PUPMAN-dot-com
• Subject: MMC vs Commercial Caps
• From: David Trimmell <davidt-at-pond-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
• Date: Thu, 17 Jun 1999 05:16:22 -0600
• Approved: twftesla-at-uswest-dot-net
• Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme

Hello to all,

I want to paste a reply I received from Plastic Capacitors, Inc. regarding
prices. It follows:


>Hello:
>
>I am interested in obtaining a quote from you folks regarding capacitors
>for use in a Tesla Coil Tank circuits, for both rotary spark gaps (with
>break rates up to 240 breaks per second), and for standard spark gaps.
>These caps will need to withstand primary tank voltages of 20 KVAC, and 25
>KVAC, and must be constructed of materials that show low loss at High
>frequency's from 30 to 500 Kilohertz, also with low internal resistance.
>These will be used in circuits with anyware from 1KVA to 10KVA primary
>power. I list the desired values of the caps bellow:
>
>1.)  20KVAC RMS -at- 0.025 uFd
>2.)  20KVAC RMS -at- 0.020 uFd
>3.)  25KVAC RMS -at- 0.025 uFd
>4.)  25KVAC RMS -at- 0.020 uFd
>
>If you have Capacitors that closely match I would very interested in price
>quotes and technical details.
>
>Thank you very much for your time,
>
>David Trimmell
>
>Thanks David,  BNZ2000-203B 3.75x2.75x14 $300.00 (.02mfd
>20KV)...........BNZ2000-253A 3.75x2.75x15 $305.00 (.025mfd 20KV)
>................BNZ2500-203A 4.75x2.75x16 $360.00 (.02mfd 25KV)
>............... BNZ2500-253A 4.75x2.75x18 $372/00 (.025mfd 25KV) .....These
>are polypropylene film, oil filled capacitors for corona free operation at
>20KVAC and 25KVAC rms.  Rectangular plastic case, dimensions in inches
>Lead time 8 weeks aro.  Tom Brown 773-489-2229 and fax 773-489-0496  >
>

These values I selected for my personal interest, but believe them to be
relative to other coilers. 
My opinion here is that the MMC is something to be reckoned with and has
added flexability for many coilers, but the price break is just not there,
unless you get them in quantities of 1000 or more. IMHO if I find ~$400 or
so burning a hole in my pocket I will buy a commercial cap, and save myself
some 16 hours or so (that 16 hours, if out of productive time, can be worth
well over $500, in itself). The 16 hours is at least what it would take me
to solder ~220 (10 strings of 22  0.056uFd 1.6kV caps, I use 1.414xDC) on a
perf board with resistors and building the case, busses, etc. Just
something to think about....

Regards,

David Trimmell

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