Re: high voltage resistors

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jim Lux by way of Terry Fritz <teslalist-at-qwest-dot-net>" <jimlux-at-earthlink-dot-net>

Sure enough, WW resistors aren't great for pulses (although, maybe the high
L isn't a problem in an application), but they do work just fine in lots of
other HV applications like bleeders, etc.  And, they are really cheap as
surplus. You just need to look at your application and decide if failure is
a problem or relatively benign.

Mark didn't say whether he was actually trying to pulse through the resistor
and what the pulse characteristics are.  I would interpret this as a
requirement for low duty cycle, high peak power, but not necessarily a fast
pulse application. An example of such an application would be an energy dump
for a stored energy system.

 > Original poster: "Mccauley, Daniel H by way of Terry Fritz
<teslalist-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>
 > Actually, wirewound resistors are the worse possible resistors to use for
HV
 > Pulse duty applications.  The inductance
 > in the resistor is much too high.
 >
 > Jim Lux wrote:
 > Wirewound resistors are normally fairly good for HV, but they have a sort
of
 > spectacular failure mode (now how would I know that?!) where an arc burns
 > back along the wire....

 >Mark Broker wrote:
 >   >
 >   > I'm looking for some inexpensive resistors that will stand off 20kV
pulses.  I have
 >   > no objections to using two or three in series.  I need a value of
30-40kohm.  I am
 >   > currently using 3 1/2W resistors in series, but question the longterm
 > standoff ability.  I have been considering the Ohmite OY series - 2W
ceramic
 >   > composition  that are about .75" long and .3"diameter, available from
Digikey.  But at
 >   > about a  buck each, I'd rather not spend $40 to discover they won't
work!
 >   >