More snubber network madness.
I need a 0.6 ohm resistor that can handle occasional short pulses of 350mJ
-- at up to 700A, but with an average power of well under a watt, and probably 3J per multi-pulse event. Derating information is hard to find. Any suggestions on just what to use?
Info on 10uF caps that can stand 700A, 1us pulses would be nice, too.
-- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
J
ttdesign.com
Ohmite publishes pulse rating info for their resistors. I had occasion to use it recently.
HTH,
James Arthur
J
I think ohmite has some called PulsEaters or something like that
-Lasse
I used to make Marx generator resistors - the internal ones (low power, long time) were generally coper sulfate saturated solution in a plastic tube with copper electrodes - the ones out at the end of the pulse line (high power, short time) were stainless steel shim stock soldered to brass contacts. The former are somewhat less stable than the latter, as well as a whole lot messier.
If you want off the shelf, someone else will have to try, but between selecting thickness, width and length you can get whatever resistance and power handling you want with a chunk of stainless (and if you overdo the power, it will let you know in an obvious manner, either by turning blue or by vanishing - I've seen both.)
Does require good soldering technique/materials (ie, not every idiot can solder stainless), but given what you do with airplane wheels, I expect you'll have no trouble.
Pulsed power is probably also where to look for your caps, but I can't recall exactly what the capacitance of various things we used was. What's the voltage come out to there? (Bring on the pedants...)
-- Cats, coffee, chocolate...vices to live by Please don't feed the trolls. Killfile and ignore them so they will go away.
Kanthal and HVR advanced power make tubular and bulk ceramic resistors that have high impulse current capability:
A low ESR/ESL polypropylene film snubber capacitor should work - for example, DCF6W10KP2-F or DCF6W10KL2-F:
Bert
-- Bert Hickman Stoneridge Engineering http://www.capturedlightning.com*********************************************************************** World's source for "Captured Lightning" Lichtenberg Figure sculptures, magnetically "shrunken" coins, and scarce/out of print technical books ***********************************************************************
Yup -- except this is for production, not playing around in my own shop for one-offs where half the fun is the time spent building. The cost/ benefit equations for "hard to do" processes are just about upside-down from one another in these two cases.
500-ish volts.-- My liberal friends think I'm a conservative kook. My conservative friends think I'm a liberal kook. Why am I not happy that they have found common ground? Tim Wescott, Communications, Control, Circuits & Software http://www.wescottdesign.com
I had an app a while back where I had used a metal film resistor in a pulse network. Resistors kept opening up and blasting a hole through the conformal coating. Changed over to carbon composition (do they still make those?) and never had a problem again.
We used some high current pulse capacitors for arc lamp ignitors. American Radionic used to have a PulseCap? line but I don't see it listed anymore. Something close would be
Looks like you got some good pointers about resistors. I'd check out wirewound ones with Ayrton-Perry low-inductance winding.
As for caps you could talk to these guys:
-- Regards, Joerg http://www.analogconsultants.com/
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This is starting to sound kind of like radar pulse forming networks.
?-)
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