Fyi the belt i use is approx. 2 inches wide and about 10 feet long. I use belts homemade from latex resistance bands and they work great with a plastic roller wrapped with electrical tape.
With current humidity levels i can pull 20 inch 'sparks' from a 14 inch diameter collector. These sparks are not always fully complete and often terminate into a plasma reaching 5 to 10 inches out from the collector.
----- Reply message -----
From: "David Speck" <Dave@xxxxxxxxxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Subject: [TCML] Voltage/power dissapation drop across HV DC current limiting resistors.
Date: Tue, Sep 29, 2015 6:27 PM
Paula,
MOTs are going in the wrong direction for this project. They have
relatively low output voltages, but very high output currents. A good
MOT can easily put out 500 mA into a short circuit, as they have only a
very small built in leakage inductance.
You don't usually begin to see corona at less than 10 KV, so even
doubling a 2200 volt MOT would only give you 4400 volts, and the amount
of stored energy plus the high current capacity of the MOT would result
in a system with a much greater lethal potential than a rectified NST.
Matt's project is looking for a moderately high voltage at a very small
current.
I'm not sure how wide his belt is, or how efficient his corona
generating electrode is, but a milliamp or less at relative low voltage
would probably be entirely sufficient for his purposes.
Dave
On 9/28/2015 8:40 PM, Paula Lange wrote:
> What about two microwave oven transformers with diodes and Voltage doubling capacitors? That would give you plus and minus 4kv.
>
> msweeney23@xxxxxxxxx wrote:
>
>> I wish i could but i need both DC polarities :(
>>
>> I know an NST is totally overkill for this but outside of using an old fkyback without the built in diode i dont see many options.
>>
>> Some 20 years ago i built this using a flyback from an old tube TV running on 12DC but it was just a curiosity and i scrapped it when building my first TC (at age 17 with no real knowledge building plate glass capacitors - lucky i didnt kill myself).
>>
>> If i could find a cheap +/- HV DC generator id be happy. Could i use a single polarity and somehow shift it down so i see a +/- half the voltage?
>>
>> ----- Reply message -----
>> From: "David Speck" <Dave@xxxxxxxxxxxxxxxx>
>> To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
>> Subject: [TCML] Voltage/power dissapation drop across HV DC current limiting resistors.
>> Date: Mon, Sep 28, 2015 11:53 AM
>>
>> Matt,
>>
>> In today's eMail I received an offer from Goldmine Electronics for a 15
>> KV negative ion generator that runs off 12 VDC for $10. It's
>> intrinsically current limited, and you can lift it with two fingers
>> instead of two men and a boy like your NST corona generator.
>>
>> If the polarity is right for your application, then it would be a simple
>> way to go. Special sale price ends 9/30. (No connection to seller, but
>> a frequent buyer).
>>
>> http://www.goldmine-elec-products.com/prodinfo.asp?number=G20855
>>
>> Dave
>>
>> On 9/27/2015 9:51 PM, Matthew Sweeney wrote:
>>> No that is exactly correct. Another user mentioned that I should be careful
>>> using NST for VDG seemingly because there could be short down in the inside
>>> of the VDG to the HV brush, allowing potentially lethal currents up to the
>>> collector. I've not been able to confirm this exact reason - maybe someone
>>> else can chime in on this.
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>
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