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Spark gap Tesla coil STILL not working...

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LAN_403

the mad scientist

Wed Jul 03 2013, 10:22PM

Registered Member #3768 Joined: Tue Mar 22 2011, 12:46AM
Location:
Posts: 107

More info can be found here:

I really need help guys, I have tried alot of things and it still isn't working, each time I test it and I fail, it kills me inside lol...

Sulaiman

Wed Jul 03 2013, 10:57PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Don't get too disheartened, here's what I would do;

- remove the MMC and check for signs of arcing on the MMC itself and on the wood below it
(I think that the two ends of the MMC may be too close)

- start at the begining, test the NST by itself, you should be able to draw an arc from ground/earth/case of the nst to either terminal of the nst, sometimes one half 'dies'
especially if you didn't have a safety spark gap ! (I can't see one)

- as mentioned in your previous thread, temporarily replace the rsg with a static sg, a fan/blower REALLY helps

- if no progress then WITH EXTREME CARE AND FORETHOUGHT (e.g. a 'minder' in case bad things happen, an easy to operate OFF switch and a handy torchlight) operate the TC in the dark, you will see what is causing the problem.

- if none of the above helps, draw a schematic of your setup by looking at the actual equipment, if it's as you intended then post a copy for us to examine.

- tuning and then fine-tuning of the primary resonant frequency is very important
I like JavaTC but other apps are available. If you need help in this area then lots of data will be required.

PhilGood

Thu Jul 04 2013, 01:54AM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

Hi,

A few additional suggestions:

- don't use alligator clips for your connections, they can give a bad contact and do not allow much current. Use ring crimps instead.

- all your wires seems a bit thin to me, I would use a higher diameter.

- measure with a DMM the resistance between the bottom of your secondary and your toroid. Tell us the value measured.

- try putting a break out point on your toroid and see if it sparks.

- try holding a neon or cfl bulb close to your secondary/toroid when the coil is running (be careful when doing this!). See if the bulb lights.

Where are each of the four wires we can see on your RSG connected to ?

Feathers

Thu Jul 04 2013, 04:05AM

Registered Member #10052 Joined: Thu Feb 07 2013, 11:31PM
Location: Overland Park, Kansas
Posts: 78

Draw a schematic of your system, and post it.

Nobody is going to be able to help you unless we have more information.

the mad scientist

Thu Jul 04 2013, 06:53PM

Registered Member #3768 Joined: Tue Mar 22 2011, 12:46AM
Location:
Posts: 107

Do you think that perhaps the spacing between the primary and secondary is a problem?

PhilGood

Thu Jul 04 2013, 10:10PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

the mad scientist wrote ...

Do you think that perhaps the spacing between the primary and secondary is a problem?

EDIT: I thought I read "arcing" instead of "spacing", thus my first answer...sorry

Is your secondary bottom properly connected to a RF ground ?

From your pics I suspect something wrong in your wiring. As other members said, please post a schematic of your actual setup. no need for a pro schematic, you can just draw it on paper.

the mad scientist

Sat Jul 06 2013, 03:56PM

Registered Member #3768 Joined: Tue Mar 22 2011, 12:46AM
Location:
Posts: 107

PhilGood wrote ...

the mad scientist wrote ...

Do you think that perhaps the spacing between the primary and secondary is a problem?

for sure it is !

Is your secondary bottom properly connected to a RF ground ?

From your pics I suspect something wrong in your wiring. As other members said, please post a schematic of your actual setup. no need for a pro schematic, you can just draw it on paper.

Here, I found the a schematic like mine on Wikipedia,

It is really frustrating me that it is not working, I am thinking of using the house's ground to ground it, I just want it to work!

Feathers

Sun Jul 07 2013, 05:14AM

Registered Member #10052 Joined: Thu Feb 07 2013, 11:31PM
Location: Overland Park, Kansas
Posts: 78

As suggested on the previous thread, turn off the rotary spark gap, and use it as two small static gaps. I mean small, maybe 1/16 of an inch each.

If you power up your NST, and the gaps are not firing, then you have a wiring problem, bad caps, or a bad NST.

Looks like you're missing a safety gap too.

I would bet that in trying to run an asynchronous rotary spark gap on an untuned coil with no safety gap, you might have fried an NST. They are fragile creatures, and must be taken careful care of.

Disconnect the NST, and try to draw an arc from each HV terminal to the NST case. If either terminal fails to arc to the case, the NST is fried. They are center-grounded, with two 7.5kV "halves" on either side (each terminal with respect to ground). They are out of phase, so the potential between the two terminals is 15kV.
Usually, one side will fail first.

I hope you get your coil running, I took out several NSTs building my first SRSGTC and know the frustration!

PhilGood

Sun Jul 07 2013, 02:49PM

Registered Member #3806 Joined: Sat Apr 02 2011, 09:20PM
Location: France
Posts: 259

Hi,

I was rather expecting a schematic of your own setup: get a paper sheet and a pencil, draw your circuit as you actually see it, then post the result.

And you do not give any feedback regarding the advices and questions that have been posted so far... makes it kinda hard to help you...

the mad scientist

Sun Jul 07 2013, 06:49PM

Registered Member #3768 Joined: Tue Mar 22 2011, 12:46AM
Location:
Posts: 107

I appreciate all the advice so far, I will draw up a schematic and post it soon.

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