[Prev][Next][Index][Thread]
Magnifer & rotary problems
----------
From: pacster-at-ibm-dot-net [SMTP:pacster-at-ibm-dot-net]
Sent: Wednesday, June 17, 1998 4:39 AM
To: tesla-at-pupman-dot-com
Subject: Magnifer & rotary problems
I finally completed my new maggy system last weekend and I just had to try
it out. As usual things didn't go as planned (sparks wall to wall), but I
managed 20" before the rotary went Kaput. I'm not very confident with my
magnifier system (this being my second attempt) so I was hoping if anyone
could help?
Most of the problems occurred in the rotary gap, the main rotor is made of
polycarb, this material was the best I had on hand so I used it. It was only
supposed to expand (by calculation) around 0.1mm at 4500rpm across it's 12"
diameter, but when I measured it during operation it had expanded almost
0.5mm which is worrying! What is the normal rotor material for rotor disks?
I read a while ago that G10 is a reasonable material, but unfortunately the
sheet plastic companies in little ol' New Zealand need a polymer name, which
I didn't have.
The rotary is of a similar design to R Hull's rotary design with pan head
screws connected in pairs around the radial edge of the disk. the problem I
had is that after I screwed the M6 screws into the disk, it developed
cracks. I'm not sure wether this is a result of the glue reacting with the
polycarb (glue was Arildite) or that the screws pressurised the air in the
hole when they were screwed into position, as the cracks developed before I
had even run the diskat any speed.Has any one had this problem and what is a
good bonding agent for metal to polycarb?
When I was finally brave enough to put the stationary electrodes in position
(backwards at the moment just in case the rotor turns to dust) I connected
the rotary up to the primary circuit. The rotary is driven by a servo motor
with a home made solid state control circuit and a 5amp fuse. As soon as I
applied power to the primary circuit the servo motor began to change speed
sporadically, as I increased the neon input voltage to 100V the motor popped
the fuse, I thought it was odd and so replaced it with a 10 amp fuse and
reapplied power. At about 100V the controller died, I replaced the broken
diode and I haven't run it since as I am confused as to why the motor would
hunt when the primary circuit was energised. I made sure that there was at
least 2" of clearance between all HV points and the motor housing and frame.
Is it possible that the high E.M. field given off by the secondary and
tertiary coils is inducing voltage spikes in the wiring running between the
motor and the control circuit? If this is the case should I get shielded
cable instead of normal 3 core wire and shield the control circuit, and then
connect the shield to mains earth or the RF ground?
After all these problems I removed the rotary and just used a variable
copper multigap (42 1.5" dia. tubes in series). When the neon input voltage
went above 80V the secondary terminal would arc to the primary coil which
was around 15" of white hot spark and there would be just a few weak
streamers off the tertiary coil. At present the toris on the secondary coil
has a 4" cross section and a mean dia. equal to that of the secondary coil.
Should I increase the tube dia. for a higher brake out voltage or would it
be better to increase the insulation between the primary and the secondary?
At the moment there is around 1/2" of polyethelene between the primary and
secondary coils but none between the torrid and the primary.
If I should increase the secondary torrid diameter will this decrease
performance or have no affect? One thing which has been confusing me for a
while now is how does performance change if the primary and tertiary
circuits have a constant L/C ratio and the secondary L/C ratio is varied up
and down?
Thanks heaps for your help and time.
Mark B.