RE: Maxwell 37667 dies interestingly...thoughts?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Lau, Gary" <Gary.Lau@xxxxxx>

Actually, the spec for this model lists a maximum continuous rep. rate
of 500 PPS.  I think the 35kV rating is just a bit light for the
application.  Maybe the 20A RMS rating is low for a pig-powered high BPS
system as well.

Regards, Gary Lau

> Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>
>
>
>
> Proper Maxwells nearly never fail.  I only had one Maxwell fail in
> twenty five years I that was because I over-volted it.
>
> I did say the "proper Maxwell".  The .03 units everyone is getting
> off the internet has two problems.  First, you have absolutely no
> idea how many cycles is has seen prior to your operating it.  Second,
> these were only designed for a few pulses per second and no where
> near the 400 pps you were operating at.
>
> The correct Maxwell, operating in it's normal range, designed for
> 100% voltage reversal, will not fail.  We have them running in
> museums all over the world literally doing shows every hour on the
> hour 24/7 with no failures in over 35 years of operating.
>
> The main problem with your .03 uF Maxwell is that is was not designed
> to operate anywhere near the pulse range you were running it at.
>
> Dr. Resonance
>
>
> ----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
> To: <tesla@xxxxxxxxxx>
> Sent: Monday, July 17, 2006 1:10 AM
> Subject: Maxwell 37667 dies interestingly...thoughts?
>
>
> >Original poster: "J. Aaron Holmes" <jaholmes@xxxxxxxxxxxxxxxxxx>
> >
> >I took my Maxwell 37667 to a friend's place over the
> >weekend to see if it would help get his new 24" coil
> >to put out some sparks.  Despite early indications
> >that things were too far from complete to run the
> >thing, we got enough wire stripped quickly enough to
> >do a temporary lash-up before daylight failed.
> >
> >Things kicked off with the destruction of two homemade
> >rolled caps that he'd spent a bunch of time on.  What
> >a bummer (and boy did they look cool, too!).  I took a
> >deep breath and offered to put the Maxwell on the
> >cooker to see what would happen.  We were immediately
> >gratified with 8- and 10-foot streamers as the break
> >rate topped 400 bps.  Yikes!  We dropped a few
> >different toploads on the thing and played around for
> >a while.  In the end, the Maxwell probably had only
> >two minutes of runtime spread over a ten-minute
> >period.
> >
> >Then, Bad Thing #1 happened:  A streamer hit the wire
> >between the Maxwell and the primary.  Due to the
> >temporary nature of the wiring, the cap had been
> >sitting relatively exposed a few feet from the base of
> >the coil.  Doh!  A metal sawhorse was quickly placed
> >over it.
> >
> >And finally, Bad Thing #2:  Shortly into the run
> >immediately following placement of the sawhorse, a
> >crack opened in the Maxwell, and the oil drained out
> >rather quickly, leaving a nice puddle of Maxwell juice
> >on the floor (VEERRRYY slippery stuff, I can now say!)
> >
> >What is quite interesting about all of this is that,
> >due to the surpise of seeing the Maxwell croak, it
> >took us a few seconds to kill the power.  In those few
> >seconds, the coil continued to operate normally; there
> >was no obvious dip in performance.  The contents of
> >the Maxwell were quite warm, though not what I'd call
> >"hot", and I neither saw nor smelled any sign of
> >burning.  On top of that, measurement revealed that
> >the capacitance was still 0.03uF, and no DC resistance
> >would register on the DMM.
> >
> >So the mode of failure here is a little unclear to me.
> >  Did thermal expansion of the contents simply pop the
> >case, or was there most likely some kind of arcing
> >fault, perhaps initiated or encouraged by the strike
> >in the prior run?
> >
> >As the Maxwell's guts seemed in remarkable shape, my
> >friend is going to try running them in a bucket of
> >mineral oil and see what happens.  I'll report back
> >with the results.  If they aren't serviceable, then
> >perhaps we'll pry them apart even more and see what we
> >find.  They were just too pretty not to get a second
> >chance :-)
> >
> >Any other thoughts on "Why Maxwells Fail"?  I never
> >even felt the thing get warm in my little coil running
> >at 120 bps.
> >
> >Regards,
> >Aaron, N7OE
> >
>
>