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Cheap Neon Sing or Furnance Ignition transformer????, pls help!!!

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LAN_403

ElectricalEngg.

Fri Feb 06 2009, 05:10PM

Registered Member #1946 Joined: Sat Jan 31 2009, 11:37AM
Location: India
Posts: 43

Hi friends
I am a student of electrical engg and this year I am gonna build a Tesla coil, this is my last year and the only way for me to finish college is to complete this project and demonstrate it.

Can someone help me find a cheap neon sign transformer or a furnance ignition transformer plzzz?

I need a rating of
6kV output and input frequency will be 50 Hz

Plzz help

Ill wait for you guys to reply

Thanks in advance

Good Day
Kashish Malhotra

Andyman

Fri Feb 06 2009, 05:39PM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

A 6 kv NST is going to be pretty easy to find. Just look around on ebay.

What is your mains voltage? How much current output do you want; 30mA, 60mA?

ElectricalEngg.

Fri Feb 06 2009, 06:00PM

Registered Member #1946 Joined: Sat Jan 31 2009, 11:37AM
Location: India
Posts: 43

Thanks mate :)
I saw both those on ebay too, but I wasn't sure of the frequency rating written on them :(
They say 60 Hz but the normal supply here is of 50 Hz in my country

My mains voltage will be 220 volts,
and I want minimum of 20 mA at my output :)

Is the frequency difference normal?

OMG!! I cant believe I have got only till tuesday to submit my estimated cost/plan of the project to my professor :(

and I always read on the internet that we should use the transformer of rating in between

6000 volts to 15000 volts

you gave a link to 5000, is that also practical to use?

Herr Zapp

Fri Feb 06 2009, 06:02PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

Kashish -

Just out of curiousity, which Electrical Engineering college are you attending that requires you to complete a "project" as a condition of graduation?

Regards,
Herr zapp

Ultra7

Fri Feb 06 2009, 08:04PM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

It would probably help us to know your location as well.
I have 7 NST's in my garage, but since you said your line freq. is 50hz, what I have doesn't help you.

TheBoozer

Fri Feb 06 2009, 10:36PM

Registered Member #1535 Joined: Wed Jun 11 2008, 11:37PM
Location: Northeastern Pennsylvania - USA
Posts: 117

As far as transformer secondary voltages go, anything that can jump a static gap could be turned into a Tesla coil provided it has the current to do it...

My tabletop model is a 3600vac 30ma. The coil puts out 7 inches...

ElectricalEngg.

Sat Feb 07 2009, 03:23AM

Registered Member #1946 Joined: Sat Jan 31 2009, 11:37AM
Location: India
Posts: 43

Herr Zapp wrote ...

Kashish -

Just out of curiousity, which Electrical Engineering college are you attending that requires you to complete a "project" as a condition of graduation?

Regards,
Herr zapp

I am in mehr chand polytechnic college India
Its something like I require at least 40% marks for passing and the marks distribution is like

50% - Theory
50% - Practical

I can never get exact 40 % or more in theory easily in fact only 0.001% chances :(

the practical marks will only be added after I finish showing them a completed project and the amount of marks will depend on how good the project was.

Andyman wrote ...

A 6 kv NST is going to be pretty easy to find. Just look around on ebay.

What is your mains voltage? How much current output do you want; 30mA, 60mA?

I aksed the sellers they said it is for domestic shipment only :(

Ultra7 wrote ...

It would probably help us to know your location as well.
I have 7 NST's in my garage, but since you said your line freq. is 50hz, what I have doesn't help you.

I am not able to think at the moment but I think there a device/instrument available for modifying the frequency
because when someone imports machinery in India its not for use on 50 Hz, they have to buy devices, I will go to market in a couple hours and let you know ^_^

TheBoozer wrote ...

As far as transformer secondary voltages go, anything that can jump a static gap could be turned into a Tesla coil provided it has the current to do it...

My tabletop model is a 3600vac 30ma. The coil puts out 7 inches...

That makes it interesting, maybe Ill have recalculate all of my project, Ill do that today itself. :)

But well the availability is still going to be a problem :(

I contacted a local transformer suppliers, they said they can make me one but that wont have the overload etc. protection and they cost like 150$ I took currency convert rattion as

1$ = 50Rs.

That becomes a huge amount in my country really huge
I can still buy that but then I will have problems in buying the rest of the stuff, and it will also make it more complicated as I will have to add more resistance stuff etc. to limit the current :(

Thank you so much for your help guys, Ill update the details I said in a few hours :)

Hon1nbo

Sat Feb 07 2009, 03:52AM

Registered Member #902 Joined: Sun Jul 15 2007, 08:17PM
Location: North Texas
Posts: 1040

try getting an actual sign to use (it can be a "dead" sign that has simply had the tubes de-gas, meaning that the voltage supply would still be fine)
(comment about removing overload is no longer suggested unless you REALLY know what you are doing... tough if you do, then it might at to your knowledge of theory and practical design)
or, I actually ran some neon sign transformers off of a 12VDC Inverter (the kind made for cars to make the socket suitable for wall based products)
since they make these inverters (which you can power off of a car battery, or any 12V supply with decent current) for a large range of power capability and prices, if you will have trouble getting a hold on a purebred neon sign, and don't want to disable the safety device (since if it's there, there is the potential for more harm than one that did not come with one as those are designed that way, so scratch my first thought)

Ultra7

Sat Feb 07 2009, 06:46AM

Registered Member #1157 Joined: Thu Dec 06 2007, 12:11PM
Location: Houston, TX
Posts: 307

I think what you probably need is our "Single Transistor Flyback" Circuit.
Hmm. . . the HvWiki is still down?
Well here is a link to what I'm talking about.

Then once you have that one built, you can do a "Plasma Tweeter" audio modulated Flyback.

This would probably earn you the quick and easy "Passing grade" until you can find a nice NST.

A Tesla coil is not the easiest "Project" to do in a crunch.
See, the issue with a Tesla Coil is not just the NST, it's everything else you need that makes it a challenging project.
If you are still set on making one, then this is the right place to have come, though.

Andyman

Sat Feb 07 2009, 09:27AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

Well, I happen to have a 277 volt primary, 12kv/30ma secondary nst gathering dust in my garage. However, it has GFI protection which is not very ideal for coil use. You might be able to fuss with it and get the circuit out of it, but that's up to you. Also, I live in California, so shipping might be a bit expensive.

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