[TCML] New Tesla Coil
kingsandangels at hotmail.com
kingsandangels at hotmail.com
Wed Oct 8 02:18:49 MDT 2008
.05mm or .5mm bare?Ill build one this size with 685mm tall I might as well build a proper Tesla Coil in England(Shortly) cuz this wire company here sux and they invoice me without confirming sizes.You guys know the exact coil size for best performance,you guys are good!Ill keep those specs handy because I think MOTs would give more power than most transformers for a tank circuit if they work like they supposed to.Thanks, Gareth
From: "bartb" <bartb at classictesla.com>
To: "Tesla Coil Mailing List" <tesla at pupman.com>
Sent: 08.10.2008 03:24
Subject: Re: [TCML] New Tesla Coil
As Scott mentioned, the secondary is very small for such a high current
supply. The h/d is ok.
But the turns of 1200 is not correct "if" 0.35mm is the "bare" wire
diameter. If it is, more like 1050 turns for single build insulation or
950 turns for heavy build insulation. The wire size is small (roughly 29
AWG). This coil will be lossy (low Q). Performance can be greatly
improved. The fix is to increase the wire size and fix the overall size
for the 4 MOT current. I would recommend .05mm bare wire size (minimum).
This size requires a longer secondary for 1200 turns. So, 685.8mm in
length and 152.4mm diameter for a nice h/d ratio (4.5). This will also
lower the frequency from 600kHz down to 230kHz. This will raise Q and
will better handle your 4 MOT system.
You can still use your MOT pack with the small 75mm x 420mm coil, but
you must greatly limit current (not voltage), otherwise your breakrate
will be very high and very lossy (you may burn up the coil from driving
it too hard if you don't limit current). Using a "fixed" MOT to limit
may not be enough. The sphere top load is ok, but a sphere's use can be
problematic if the sphere is too small. A toroid would greatly reduce
top coil breakout and corona. Salt water caps work, but they are very
lossy (corona losses). All these losses rob power from the coil and
reduce spark length performance.
Looking back at my coil recommendations (above), I realize they are
Scott's recommendations. We both arrived at the same coil size and
likely in the same way. How cool is that!
kingsandangels at hotmail.com wrote:
> Hey everyone, Bart Im building a secondary of 75mm diameter with .35mm wire I want it 1200 turns which will give me 420mm height which is more than 375mm (5:1 ratio) What do you think is best for performance,Can I go more than 5:1 ratio? Oh we also get polyuathane but in varnish for floors only,is that correct? Can fiberglass resin also do the trick? The spark length on my 4 mots dont look long and you supposed to use a rotary spark gap,can anyone help me with mots(Is it also necessary to disconnect the outer mots from the core to prevent arcing?) Bart whats your take on my secondary? Im going to take my secondary and my copper sphere to the UK and make more! Thanks again Gareth
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