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Registered Member #158
Joined: Sun Feb 12 2006, 09:53PM
Location: Central Ohio
Posts: 282
J. Aaron Holmes wrote ...
I've blown up these Maxwell 37667's before, and if any of you have done any reading on TCML you'll know that they're scarcely recommended there either. The voltage reversal characteristics are awful. You really want almost 2x Vpeak with these, which makes them non-economical.
Cheers, Aaron, N7OE
A quick search on tcml and I see what your talking about. The other maxwell pulse caps I got seem top notch, I just assumed there too... Thats cool, I didnt even know the TCML was still active, I havent been an active poster there since the 90's.
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
Quantum Singularity wrote ...
A quick search on tcml and I see what your talking about. The other maxwell pulse caps I got seem top notch, I just assumed there too... Thats cool, I didnt even know the TCML was still active, I havent been an active poster there since the 90's.
TCML is still alive and, I dare say, the better place to take SGTC questions. The solid-state coilers probably have better luck here. Overall, I enjoy 4HV a bit more in general (despite being an SGTC'er) because plain text emails get "old" fast
But back on topic: Most of the Maxwell pulse caps I've seen (not just the 37667's) are pretty weak on the voltage reversal. This can be compensated for by using the higher voltage ratings or more caps in series, of course. Friend and fellow Seattle area TC'er Matt Stiger uses a 2x3 MMC of 37667s, and he has done ok. He also used some of the 50kV .01uF Maxwells (forget the part number), and those were ok, but he couldn't find enough of them affordably. I ran a single 37667 at 120 breaks/s with a 14.7kV pig and got away with it for a while, but when I cranked up the break rate the ends blew off and oil went everywhere. I cleaned up the guts and put them in a plastic sandwhich box with fresh Diala AX transformer oil and they ran about a minute and then blew up again
When you take into consideration the fact that a few 37667's are needed to accomodate the voltage reversal issue for a 14+kV pig, the CDE 942's are suddenly more affordable And the best part is that you don't have to design around your capacitor, since you can build just about any size cap you want with the 942's. They're good stuff!
Registered Member #1370
Joined: Mon Mar 03 2008, 09:01AM
Location: Finland
Posts: 56
teslacoolguy wrote ...
What is exactly place X
I didn't know that place, so I asked it. Seems now like that it will be Richardson Electronics. Thanks lot of that CJE info, I was about to buy them! But now, if I can't get any other, I'll buy CDE.
Registered Member #1034
Joined: Sat Sept 29 2007, 12:50PM
Location: Chillicothe, Ohio
Posts: 154
I haven't seen many people make their own capacitors here lately but back in the 90's Richard Hull and the TCBOR group had some success making rolled capacitors out of low density polyethylene plastic and aluminum flashing. The finished capacitor was rolled up and put into a closed PVC pipe that was filled with mineral oil.
The mineral oil they used was the type you buy in the pharmacy in the little bottles. It's kind of expensive but I have found you can get the same thing in the farm supply store for $10.00 a gallon.
The only drawback to them that I know of is that they aren't as compact as commercially made capacitors but they are more compact than beer bottle or wine bottle capacitors.
Given what might be available today l don't know if it still practical to do all that.
Registered Member #477
Joined: Tue Jun 20 2006, 11:51PM
Location: Seattle, WA
Posts: 546
RogerInOhio wrote ...
The mineral oil they used was the type you buy in the pharmacy in the little bottles. It's kind of expensive but I have found you can get the same thing in the farm supply store for $10.00 a gallon.
$10/gal is what I pay for Diala AX transformer oil in 5 gal pails from the local oil joint. Best to get that if you can find it for a competitive price in your area. The farm stuff is meant to dump down cows to help them poop. Since longevity isn't a major concern, the farm stuff also doesn't have all the anti-oxidation and anti-biology substances that transformer oils has. So it can "go bad" to a certain extent.
Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
Ahhhhh i have been calling just about every electronics destributor in the united states and the quotes are either to expensive or there is a 10 month lead time. Anybody want to help me sample some.
Registered Member #1107
Joined: Thu Nov 08 2007, 10:09PM
Location:
Posts: 792
Well when i called them up they sead that they had a 9 month lead time on them so i dont know if that is true of if the person i was talking to dident know what he was talking about.
Registered Member #1157
Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307
As crazy as it sounds, I think This guy has some, but he is charging through the nose to get them.
I have probably 12 left, and I need them. . . Sorry. Richardson is the place to get them, but I think we have to pool together a bunch of us and order a big bulk.
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best capacitor for the coil im building
And the best part is that you don't have to design around your capacitor, since you can build just about any size cap you want with the 942's. They're good stuff!
