Re: Yet Another Lo-Budget MOT Experiment

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

Original poster: "Jolyon Vater Cox by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jolyon-at-vatercox.freeserve.co.uk>

Have you considered using a triggered gap with the MOTs?
How about using an ignition coil to supply pulses at higher voltage but
lower current than the MOTs to gate the main discharge?

which would be triggered when a spark from one of the main electrodes
attached itself to the ionized channel of a "pilot" spark between the
trigger electrode and the other main electrode -"closing the switch" so as
to speak.

Maybe you could even try a "pseudo-spark" -switch
they are supposed to be very fast- although I don't know if anyone on the
List has ever used these or whether it is feasible to build them without
specialised equipment!

Jolyon
---- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Monday, November 11, 2002 7:50 PM
Subject: Yet Another Lo-Budget MOT Experiment


 > Original poster: "Gregory Hunter by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>
 >
 > Dear List,
 >
 > I just tried the low-voltage high-current approach
 > again using only two series MOTs for ~4kvac, no
 > doublers, no RF filter, and no ballast. Power was
 > provided by a 240vac/20A window A/C outlet:
 >
 > http://hot-streamer-dot-com/greg/madness7.jpg
 >
 > The Tesla coil was my new & improved junk box coil
 > with a new primary, 4" sch 40 PVC wound for 24" with
 > 28AWG. Top load was 4" x 20" dryer duct toroid. Tank
 > cap was 128nf (81nF of beer bottles in parallel with
 > 47nF MMC). Spark gap was inside-out sucker gap
 > quenched with a vacuum cleaner motor (air blown single
 > static).
 >
 > Performance was pretty good--better than I expected
 > anyway. The gap setting proved to be hyper-critical. A
 > micron too wide, and firing was sporadic. An angstrom
 > too narrow, and it quickly decayed to power arc. Once
 > I got it set just right, I could run a couple of
 > minutes or more before I felt compelled to switch off
 > the MOTs so the gap could cool awhile.
 >
 > Sparks were thick, intense, and frantic. I got plenty
 > of strikes out to 5 feet or so, which sort of
 > surprised me. I might have to try this again with a
 > water or oil cooled gap. I also noticed my motor oil
 > immersed MOT twins got very hot. I cracked the lid of
 > the ammo can and a puff of oil smoke came out! Maybe a
 > bigger oil bath is in order!
 >
 > I'm still not satisfied with the utility of this
 > setup. Going up to 8kvac with 4 series MOTs solves so
 > many problems and makes things more stable and
 > predictable. Still, I intend to do some more 4kv
 > experimenting--just for grins.
 >
 > Regards,
 >
 > =====
 > Gregory R. Hunter
 >
 > http://hot-streamer-dot-com/greg
 >
 > _