[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: [TCML] Please help with my non-working tesla coil.

i believe that simplicity is the key to first-time Tesla coilers. my master gap consists of 2 1/8" Ti-Ni-Mo rods inserted through holes drilled in the centre of 2 CPU chip aluminium heat-sinks. this is very easy to adjust, and stays cool enough even without a cooling fan, such that the aluminium heat-sinks are cool enough to be held in my palm even after half-hour runs of my 15/30 NST powered coil. copper or brass rods offer slightly lower resistance, but i chose the rods for their sheer durability (showing hardly any signs of erosion even after close to a hundred hours of run-time).
the safety gap is as central to the operation of the coil as is the master gap. i always set my safety gap to precisely 15KV without fail before the start of any session, and then play around freely with the separation of the master gap for optimal performance, stopping the coil as soon as the safety gap fires. i find that the quenching ability of an increase in distance between the master gap effectively compensates for the lack of a cooling/quenching fan, as long as it is operated within the potential range allowed by the safety gap.
another thing i have noticed is your LTR value of 22nF for your cap bank. according to WinTesla, the resonant cap value for 30mA is 6.4nF, and i use a LTR 9.6nF cap bank. i am not sure if there is a problem of 'over capacitance' resulting in poorer resonance etc. as i have no experience in this area; maybe someone else could advise.
judging from the fact that you coil puts out 5" sparks, it is unlikely that you have significant problems with your tank circuit. from my past experience, when i initially fired my coil, my powering circuitry was separate from my primary coil, and i soon noticed primary current arcing through the insulation of the 7-stranded high current cable i was using. nothing short of 50KV TV/HAM wire or 100KV X-ray cable will do for connecting separate primary components, though the best thing would be to mount the circuitry and spark gaps directly under the coils (as i subsequently did) to eliminate the need for long connecting cables or primary losses.
tuning your coil probably isn't a problem for you as well. i have experimented with changing the angle of my flat spiral coil from 0 degrees through to 45 degrees external angular elevation with no discernible difference in spark length, thus i would advise you to stick to the flat archimedes spiral configuration, unless your coil is of the helical primary/secondary configuration. 
my secondary coil is 4.5" by 25", wound with 22.5 AWG, with a topload of 15" diameter of 6.5" aluminuim ducting. it hardly broke out at all till after 2 weeks of running and tuning. judging from your picture, and taking the spark to be a 5" reference, your topload seems to be of similar dimensions to mine, which would be too big for the supplied power, probably explaining the lack of streamers. you could try using smaller ducting for a smaller torroid, or upgrading your power source to parallel or higher power NSTs, or a MOT stack, which your cap bank should be able to handle.
anyway, my coil is grossly under-powered with a primary of 17.5 turns of 0.55" spaced 100' of 0.25" copper pipe on 4' by 4' of varnished plywood, further mounted by 8 3/8" threaded steel rods over the powering circuitry which  rests on another foam-insulated 4' by 4' plywood board on 6 large castor wheels for mobility. the whole set-up is about 7' tall, truly an over-kill for a 225W equivalent coil. it would probably do better with a 5KW MOT stack/mini-pig though the spark gap and cap bank would have to be correspondingly upgraded. it currently puts out 9" streamers, and weak 6" break-out only visible in the dark. very wimpy... but low enough in power to touch without getting killed, allowing me to do Sith 'force lightning' stunts :p
Regards,jeremySingapore

> From: cho_yan_ping@xxxxxxxxxxx
> To: tesla@xxxxxxxxxx
> Subject: RE: [TCML] Please help with my non-working tesla coil.
> Date: Fri, 24 Jul 2009 21:58:21 +0800
> CC: 
> 
> 
> Hi Gary,
> 
> I posted two photos on http://drop.io/chester_tesla1.
> The first photo is my multi static sparks gap, which I used 4, and total length is 4mm.
> The second photo is a 5"sparks obtained by bending the bottom terminal to the top by a wire.The sparks obtained in this way is weak, and not likely due to resonance. 
> Also I have to raise the primary until half the height of the secondary coil. So I don't think that my coil is working.
> 
> I am thinking if my coil is out of tune or problem of grounding?
> I calculate by Teslamap and tapped at 4-6 microHenries, but no open air discharge or corona is obtained.
> I tried to ground by a 15sq. foot iron fence, no result obtained.
> I also tried to use main ground, I don't know if this could hurt if only lamp and fan are connected in the same circuit.
> However, still no open air discharge obtained.
> 
> What should I do to diagnose and the problems?
> Thanks for any advice!
> 
> Regards,
> Chester
> 
> 
> 
> 
> 
> --?寄的?件附件--
> From: Gary.Lau@xxxxxx
> CC: 
> To: tesla@xxxxxxxxxx
> Date: Thu, 23 Jul 2009 17:05:51 +0000
> Subject: RE: [TCML] Please help with my non-working tesla coil.
> 
> Hi Chester,
>  
> We'll need to know a lot more before we can diagnose the problem.  Is there a way you can post detailed photos of your coil, in particular the spark gap, and relationship of primary & secondary coils?  There should never be sparks between the pri & sec.
>  
> When you chose the tap point for the primary, was this based on an observation that performance seemed better at that tap than with more or fewer turns?  In other words, do you have any idea if you are in tune?
>  
> Assuming that the stated inductances are correct, we can calculate the primary frequency, but to calculate the secondary frequency we'd need to know the dimensions of the top load.
>  
> For your spark gap, is the 4mm the total spacing (sum of individual gaps)?  The typical method of setting the gap width is to set it so that it just fires when only the NST is connected to the gap.
>  
> A polypropylene MMC is without doubt a much better choice than a bottle cap.
>  
> Adding forced airflow through the spark gap usually helps, but I'll reserve that comment until I see photos.
>  
> Regards, Gary Lau
> MA, USA
> _________________________________________________________________
> ?您喜?的人在?上分享回?。
> http://www.microsoft.com/hk/windows/chinese/windowslive/products/photos-share.aspx?tab=1
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla

_________________________________________________________________
Share your memories online with anyone you want.
http://www.microsoft.com/singapore/windows/windowslive/products/photos-share.aspx?tab=1
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla