Magnifer & rotary problems

From:  D.C. Cox [SMTP:DR.RESONANCE-at-next-wave-dot-net]
Sent:  Thursday, June 18, 1998 1:25 PM
To:  Tesla List
Subject:  Re: Magnifer & rotary problems

to: Mark

Polycarb is not a good rotor material choice.  It will not take the high
heat generated with the cap discharges.  G-10 is a glass laminate phenolic
(green in color) and works well as rotors.  Also, machine the electrodes
for a very tight press fit -- do not use any type of adhesive to hold them
in place.  The different thermal expansion values for glues and rotor
materials will cause rapid failures which could injure you or a friend if
the rotor explodes.


> From: Tesla List <tesla-at-pupman-dot-com>
> To: 'Tesla List' <tesla-at-pupman-dot-com>
> Subject: Magnifer & rotary problems
> Date: Wednesday, June 17, 1998 10:14 PM
> ----------
> 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
> 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
> polycarb, this material was the best I had on hand so I used it. It was
> supposed to expand (by calculation) around 0.1mm at 4500rpm across it's
> 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
> I read a while ago that G10 is a reasonable material, but unfortunately
> sheet plastic companies in little ol' New Zealand need a polymer name,
> 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
> 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
> polycarb (glue was Arildite) or that the screws pressurised the air in
> hole when they were screwed into position, as the cracks developed before
> 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
> (backwards at the moment just in case the rotor turns to dust) I
> the rotary up to the primary circuit. The rotary is driven by a servo
> with a home made solid state control circuit and a 5amp fuse. As soon as
> applied power to the primary circuit the servo motor began to change
> sporadically, as I increased the neon input voltage to 100V the motor
> 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
> hunt when the primary circuit was energised. I made sure that there was
> least 2" of clearance between all HV points and the motor housing and
> 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
> 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
> 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
> went above 80V  the secondary terminal would arc to the primary coil
> 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
> has a 4" cross section and a mean dia. equal to that of the secondary
> Should I increase the tube dia. for a higher brake out  voltage or would
> be better to increase the insulation between the primary and the
> At the moment there is around 1/2" of  polyethelene between the primary
> 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
> 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
> and down?
> Thanks heaps for your help and time.
> Mark B.