Re: [TCML] Secondary Wire splice technique, gear reducer 4 sale

[quarkster@xxxxxxx]

Jim -
 
1. I think you can find much better pricing on your magnet wire if you look around, especially if you can find "odd size" wire (odd AWG numbers, like half-sizes, etc). I'd also try to find a single spool with enough wire so that it would not be necessary to make a splice half-way up the secondary. No matter how carefully you make the splice, it will be visible and look like an "oops" occurred. Aside from 5 and 10 lb spools, magnet wire is also sold in 75-80 lb "buckets" with a large spool inside. For an example, there is a current eBay listing (320401817290) for an 80 lb bucket/spool of #19.5 AWG "heavy" insulation magnet wire starting at $199. You could buy this, wind your secondary without any any splices, sell the remaining wire on eBay and recoup most of your wire cost. (In the past, prior to the "copper price bubble", I purchased several 75lb spools of #17.5 AWG copper magnet wire for around $50 each at a structural metals supplier. How they
 ended up with magnet wire I don't know, but they were anxious to get rid of it.)
 
2. I am very pleased with the results I get using Envirotex Lite Pour-On 2-part epoxy for coating my secondary coils. It does take a pretty well-controlled process to get perfect results. I have previously posted a complete, step-by-step coating procedure here on the TCML; check the archives for "Envirotex Lite", "Pour-On coating", "Secondary Coating Process" etc.
 
3. I have built several secondary winders, and have found that using a DC gearmotor at very low voltage works best for me, as the available torque is very low, and its very easy to stop the whole system nearly instantly if there is any snag or other problem feeding the wire. Any other kins of solid-state  speed control can be problematic, as they will increase drive current dramatically when they sense the motor slowing down, trying to maintain constant speed, which is exactly what you DON'T want. On some gearmotors to even further reduce torque  I've run them powering the field windings only, with the residual magnetism in the armature being enough to make the motor run, but at very low torque. Select a gear reduction ratio that would give a higher output speed than you really need, so the motor armature is turning quite slowly, compared to its rated speed. This way, if you need to stop quickly, there is not a lot of "coasting" time as the heavy
 armature slows to a stop.
 
Regards,
Herr Zapp
 


--- On Sun, 7/26/09, Jim Mora <wavetuner@xxxxxxxxx> wrote:


From: Jim Mora <wavetuner@xxxxxxxxx>
Subject: [TCML] Secondary Wire splice technique, gear reducer 4 sale
To: "'Tesla Coil Mailing List'" <tesla@xxxxxxxxxx>
Date: Sunday, July 26, 2009, 2:24 AM


Hello Friends and Fellow Coilers,

(1) I am preparing to wind nearly 22 pounds of #18 >200 degree wire. This is
available to me on 11 lb spools at near $100/ spool. Is this a good price?
Can I get 22lb joined or bigger spool? I emailed Essex but they never
emailed me back:-( I know how to silver solder a tapered splice which
shouldn't be too hard with this size wire. My question is what to coat the
splice with of very high dielectric coating properties? I want to keep the
windings adjacent for ascetics. 

(2) I do plan on my usual few coats of polyurethane and may try my luck with
pour on 2 part epoxy (never tried before by me)...I can deal with drools!
This is a ~7500VA coil.  I guess I would want a slow cure product and of
course constant turning. I would appreciate some experienced responses of
conquered or failure mode hard knocks on these issues. What's a good pour on
product and application techniques? This is a new .125" thick 12.25" PVC
former a big 5:1 ratio. It is getting a 56-60 x 12" top hat to shield the
coil. I can give more design specifics if anyone is interested.

I am building a mucho winder with a worm reduction gear box and an AC freq
controller .5hz- 360hz near constant torque. It makes up to 3 hp 3 phase
from single phase 240v, the next wind is a 22-24" sono tube. I'm using 2"
thick wall hard conduit as the axle. The weather is hot and very dry this
time of year in Ojai, Ca. - Good time to coat and wind!

Thanks Much,
Jim Mora

For Sale:
I have a smaller gear reducer .5" in (1/2" VS drill would be a great driver)
output 5/8" 13:1 ratio I believe it is 175 in-pounds of torque. It looks as
new and turns freely with zero end play. I decided to go mongo (heavy duty)
for the sono tube on the same rig. How does $30 sound? Just use a wide type
fan belt on a 2"x 5/8" shaft alternator pulley and wrap the flat belt around
the end of the coil form. A used timing belt would work well too.





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