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[RE]Motors and MOTS misbehaving.



Original poster: "M G" <gt4awd@xxxxxxxxx>


Hi Scott, I am not an expert and cannot really help towards answering what is wrong with your motor, but I can say this. For my first coil setup I had added an old desktop fan for some slight quenching on the gap and to cool all the components. It was working fine, and eventually I had the coil tuned decent enough to run full power with all gaps firing. Right when I turned on the coil the fan blades, made of plastic, broke into several pieces.



There's no way of knowing if the coil caused this, but considering it happend exactly as I turned the coil on, I would have to say it played a role in the destruction of this old fan. If I had to guess I would say turning the coil on caused a large current and/or voltage spike in the fan motor. The fan was on the same mains line as the coil. I have noticed that anything metal near the coil picks up a lot of the RF electricity.



If you place a flourescent bulb about three feet away from the coil on the mains line powering the setup, and turn on the coil, you will notice it partially lights up when it normally would not from that distance in the air. Because of this I have decided to relocated my RFI filter as far from the coil as possible. I will be building a small unit to encase the RFI filter, which will be placed right by the outlet.



Matt G.

---------[ Received Mail Content ]----------
Subject : Motors and MOTS misbehaving.
Date : Tue, 27 Mar 2007 00:07:07 -0600
From : "Tesla list" <tesla@xxxxxxxxxx>
To : tesla@xxxxxxxxxx

Original poster: "Scott Bogard"

Hi All,
I have been building and playing with my
6-in 6-MOT tesla coil lately, and 2 strange and
slightly disconcerting things are
happening. Firstly I keep burining out MOTs (I
have a bunch, but I would like to run it two
nights in a row without replacing part of the
power supply). I am using a filter composed of a
bunch of ceramic capacitors to ground (a total of
600 pf, 300 from -6kV to +6kV, and 150 from +6kV
to ground, and 150 from -6kV to ground), and two
wire wound resistors, filled with welding rods
(so they are kind of inductors, I don't have a
clue what the inductance is, but the resistance
is 50 ohms a piece) and of course safty gaps
(which do fire, when it is out of tune (like when
I am using small top loads, or my blower is too
slow)). Tonight, one of the mots toward the
center burned out (how is this possible?). I
noticed some power arcing in the spark gap right before it went.
Secondly, I have a motor, running a blower for my spark gap.
Origionally, it was in tended for an ASRG, but it
slowed down considerably when I turned on the
power. So I moved it onto a differant breaker
thinking it was a power draw issue, it didn't
help. So, I checked for high voltage leaking in,
I found some, fixed it, and the motor still
slowed down. So, I gave up on it for an ASRG, as
obviously it was just not strong enought for the
job, and now I'm using it as a blower, it still
slows down. I replaced the dimmer switch
controlling it with a variac, it still slows
down. It works fine at full speed, but once you
reduce the speed to about half it starts doing
wierd stuff. I did an experiment earlier, and
noticed somthing bizzarre, when I use a small
topload (or no top load at all), the bahavior is
much more extreme (It almost stops!). The motor
is an AC/DC 15000RPM 1/8HP vacuum cleaner motor,
and although the case is plastic, it is mostly
sheilded by sheet metal and the blower housing (I
don't believe they are grounded however). Does
anyone have any experience on this? Thanks for your input.
Scott Bogard.


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