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Re: NST Pulse Voltage- getting pole pigs

Original poster: "Chris Rutherford" <chris1@xxxxxxxxxxxxxxxxxxx>

Hi Steve,

I have four NSTs that I got from Turnwell all wired in parallel giving 10KV @100mA. I have made a DC multiplier with 48 diodes (4 lots of 12 in series) and 6 MO capacitors and a MOT, 11KV OK, but the problem here was power arching and the 'Inductive Charger'. I used 6 series HT valve amp smoothing chokes to separate the DC psu from the primary LC circuit, but the chokes only lasted for about 10 mins before the insulation burnt. I have found a local winding company who may be able to help me wind a proper HV charger for a DC psu. The only problem with the inductive charger is that you limit the bang rate due to the changing reactance at different bang rates, I have a 3000bps bi-dir DC asrg. I suppose a high voltage variable impedance 0-10H choke is what I need to complete my MOT DC multiplier project. - Either that or a fan heater load on the MOT primary.

Does 4K look reasonable for a pole pig?

Thanks

Chris R

----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, August 16, 2005 12:41 AM
Subject: Re: NST Pulse Voltage- getting pole pigs


Original poster: Steve Conner <steve@xxxxxxxxxxxx>


Does anyone know a good place to get pole pigs from in the UK at scrap prices for repair?

You already noticed that we're not so keen on neon signs as the Americans. But pole pigs seem quite rare in the UK too. We don't need so many because we use a sensible mains voltage! *grin*

You just missed a pig- it was grabbed within minutes of getting advertised on the UK Tesla mailing list, on Friday or thereabouts. I've been coiling for 3-4 years now and only seen a couple of pigs for sale in that time.

There are lots of alternatives to NSTs and pigs for the British coiler. Solid state and DC resonant coils have always been popular here. A DC coil can produce great big sparks from a couple of MOTs without stressing the insulation as a stack does. The best I have seen is almost 7ft from two MOTs, and I have managed about 4ft from a single MOT. However DC coils need extra capacitors, HV diodes, and iron-cored inductors that add to the cost and hassle.

You can also try MOT stacks, paralleled oil burner ignition transformers, Thor-style switched-mode supplies, you name it. If you're feeling rich, you can even buy new NSTs from Tunewell Transformers.


Steve Conner