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Re: RF caps for MMC construction - Mixed Up Comparison
Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-qwest-dot-net>" <vanyo-at-echoes-dot-net>
OK, I'm confused (or perhaps not).
It seems that whatever voltage and capacitance combination is available
in the Cornell-Dubilier 942C series (such as the "Geek Group" 942C20P15K
.15uF 2KVdc caps), is also available in the 943C series. The
differences are: a) form factor (942C cylyndrical, 943C rectangular) and
Average RMS Current rating, which, for some voltage & capacitance
combinations, is higher in the 942C series, and for others is higher in
the 943C series.
Now, the cap you mention is 943C16S33K, which is rated 1600Vdc and
0.033uF (*NOT* 0.33uF). I suspect you meant the 943C16P33K (note 'S'
versus 'P' in product number). I suspect this because the prices of
their 942C counterparts (Richardson Electronics doesn't list the 943C
prices) are $0.90 and $2.59 respectively (you said $2.59).
So let's compare:
1600Vdc 0.033uF
---------------
#1. 942c16s33k - Average RMS Current = 1.5A Price = $0.90
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=79380
#2. 943c16s33k - Average RMS Current = 1.7A Price = ?
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=145599
1600Vdc 0.33uF
---------------
#3. 942c16p33k - Average RMS Current = 8.3A Price = $2.59
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=159547
#4. 943c16p33k - Average RMS Current = 9.2A Price = ?
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=96878
2000Vdc 0.15uF
---------------
#5. 942c20p15k - Average RMS Current = 5.6A Price = $2.52
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=162589
#6. 943c20p15k - Average RMS Current = 4.8A Price = ?
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=99974
The Geek group caps are #5, and have a better current rating than their
943C counterpart.
#1 is the part number and current rating you mentioned, but #3 is the
capacitance and price (assuming same price for 942C and 943C) you
mentioned, and similar part number.
So I don't know what comparisons are to be drawn. But, as I mentioned
earlier, the following cap:
3000Vdc 0.047uF
---------------
#7. 940C30S47K - Average RMS Current rating = 2.3A Price = $1.22
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=164077
looks, from it's ratings, like it might be usable. At least some people
once thought so. Indeed, I have a bunch of them collecting dust, that I
bought before reading about others experiences with them (they go up in
smoke). So I personally wouldn't invest in 943C's based on their
ratings alone. I'm sure it would be easy enough to determine if the
943's have the same flaw as the 940's. Or am I wrong? Can one tell by
the current rating alone (for a given voltage and capacitance)?
Now, if you're willing to go with the 1600Vdc rating instead of the Geek
Group caps 2000Vdc rating, they've got 942c16p's and 943c16p's with
capacitance from 0.1uF up to 0.68uF (the 2000Vdc caps only go up to
0.15uF - the Geek Group cap size). The 942c16p68k and 942c16p68k
(1600Vdc, 0.68uF) have Average RMS Current ratings of 14.5A and 16A
respectively. The 942c16p68k's are $4.27 each. Anyone want to calculate
how these would compare in MMC use? The two factors being total cost,
and total number of caps needed (less caps might even be worth more
total cost to some, from an aesthetic point of view, compactness, ease
of MMC construction, ...).
942C16P68K
http://catalog.rell-dot-com/rellecom/scripts/SkuPage.asp?SKU=165330
All the above numbers taken from http://www.rell-dot-com
- Bill Vanyo
Tesla list wrote:
>
> Original poster: "D.C. Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<resonance-at-jvlnet-dot-com>
>
> Cornell-Dubilier RF Snubber caps, p/n 943C16S33K, 0.33 uF, 1600 VDC.
> Available from Richardson Electronics, tel. 800-323-1770, at $2.59/pc. This
> is a rectangular cap and has higher peak current (1.7 A vs 1.5 A) than the
> round ones.
>
> Dr. Resonance
>
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Friday, August 09, 2002 4:59 AM
> Subject: RE: Possible capacitor
>
> > Original poster: "Dave Hartwick by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <ddhartwick-at-earthlink-dot-net>
> >
> > Josh,
> > I never tried wine bottles. I must say that though I think plastic is the
> > better performer, glass is nearly indestructible and easier to procure.
> >
> > The geek group caps--I've been to that site and I'll be darned if I can
> find
> > reference to capacitors there. I'm on the verge of ordering the .056 mfd
> > Panasonics from Digikey.
> > Dave Hartwick
> >
> >
> > Original poster: "J Dow by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> > <jdowphotography-at-hotmail-dot-com>
> >
> > you could make an ok cap with those
> > but if you are going to make salt water caps
> > I put my money on wine bottles.
> >
> > I used 8 wine bottles in one of my first coils that was powered buy a
> 15/30
> > nst
> > and they worked rather well. If youre still in the beginner phase of
> > coiling I would highly recommend salt water caps. They will take anything
> > you can through at them with out failing. If they do fail they are cheep
> to
> > fix.
> > If youre a more advanced coiler I would suggest making and investment in
> > Geek Group Caps. They arent as cheep as salt caps but they give better
> > performance and do VERY well under stress.
> >
> > Let us know how you make out
> >
> > Read you later
> > Josh
> >
> >
> > _________________________________________________________________
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> >
> >
> >
> >
> >