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LAN_403

Part Scavenger

Mon Jun 04 2007, 03:37AM

Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673

BTW, your toroid is way too small. That won't be keeping you from having sparks though. If you're wanting to use a round one, a basket ball sized something would be about right?

Didn't really understand the diagram you posted but here's how it should be:
Power from the wall goes into the NST. The NST goes parallel with the MMC, and the primary and spark gap should be in series between both poles of the MMC. The MMC is NOT in series with the primary.

The secondary is grounded to RF ground, basically that means a rod driven in the ground, cold water pipe, really big piece of metal, etc. The first option is preferred.

Not really sure what's causing the breaker to pop, first try checking your shematic, make sure you ground your secondary, and we'll see what happens then.

Generally, to short out the caps, I just short the spark gap with a screwdriver, one you don't care for much. Other people use a jumper with a high watt resistor or something. This will only work if you have the MMC installed correctly! When the TC is not in use, be sure to short the spark gap with something. Just put a jumper across it or something.

Nice construction BTW, I'd like to see a better pic of it! Should be pretty when you're finished. ;)

Yongsoo

Mon Jun 04 2007, 04:04AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Ah, I had them all in a series. Thanks, I'll try again tomorrow.

How wide should my spark gap be? I'm using 2 1/4 inch tungsten electrodes about a cm away from each other.

How do I attach the secondary to the ground? Would attaching the bottom of my coil to a cold water pipe work?

GreySoul

Mon Jun 04 2007, 04:34AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

hrm.... it sounds like you might be trying to feed your caps into your house wiring or something? Probably not good whatever it is.

Here's a sites with very basic schematic for wiring your coil. the HV in are the two high voltage points on the NST.

-Doug

Part Scavenger

Mon Jun 04 2007, 12:29PM

Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673

Yongsoo wrote ...

Ah, I had them all in a series. Thanks, I'll try again tomorrow.

How wide should my spark gap be? I'm using 2 1/4 inch tungsten electrodes about a cm away from each other.

How do I attach the secondary to the ground? Would attaching the bottom of my coil to a cold water pipe work?

Your spark gap should be set as follows. I'm assuming you have an NST, so correct me if I'm wrong.

1. Take the spark gap and the NST all by themselves.
2. Connect the spark gap poles to the NST's poles, they'll be in parallel.
3. Set the spark gap so that it just jumps across the gap.
4. Your spark gap is set. You may set the gap smaller, though I don't know why you'd want to, and NEVER set it any wider for this may exceed the voltage rating of your NST.

The secondary is attached by simply connecting the bottom wire coming out of the secondary to ground. So yes, you are correct.

Yongsoo

Mon Jun 04 2007, 06:38PM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

I'm not sure how I make the spark gap wider without making it too wide. Is it okay if I run the NST with a spark gap that's too wide for a second? Also, do I ground the transformer the same way I ground my secondary and strike rail or do I use the grounding on the extension cable connected to the wall socket?

Part Scavenger

Mon Jun 04 2007, 10:28PM

Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673

Not a good idea to run the NST too wide in TC use You can open it as wide as you want all day as long as you don't attach the MMC. The voltage likes to ring up between the primary and MMC and overvolt the NST. Kinda of the same idea as Tesla's vision for the secondary, only it's happening in the primary circuit. The spark gap limits the voltage in the primary circuit, so setting it so it will just jump across on an unloaded NST sets the gap at the NST's maximum voltage. If you set it wider than that (and connect it to the TC), the voltage in the primary circuit will ring up and the spark gap will still fire, but now you would be overvolting the NST. To keep this from happening, some people use a safety gap to protect the NST.

Yongsoo

Tue Jun 05 2007, 02:44AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

I grounded the NST, strike rail, and secondary coil. I rearranged my wiring to match this picture exactly.

Still no results. The spark gap fires once and only once then parts of the MMC light up. My primary consists of 6 coils and my secondary consists of ~1200 coils and I didn't wind them perfectly if that might change anything. Not to sure why it's not working. Any suggestions? I think another problem might be in my MMC as I did a poor job soldering everything together. The ends are pretty close to each other and they might be sparking across and not following the series.

Coronafix

Tue Jun 05 2007, 02:58AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

It sounds like a bit of a worry if your MMC is lighting up!

Can you give us some details of the MMC, what size cap, what size resistors,
how many caps and in what array?
Post a picture of the MMC if you can.
Here is a TC calculator you can mess around with to find the right configuration
for your coil.

GreySoul

Tue Jun 05 2007, 03:00AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

Can you get a good picture of your MMC? It almost sounds like you have a short in the MMC, or at least a bad connection. Try closing your sparkgap down to like 2-3mm and see what happens. (dont do this while it's on, of course).

Did you use a MM to check the resistance of every junction in the circuit? If anything is above 1-2 ohms you probably have a problem... ideally the solder joint between 2 leads of the capacitors should read as close to 0 as your meter reads. 0.5 ohms or lower.

As for perfect wiring... meh... your first coil doesn't have to be perfect to work. you SHOULD get some sparks even out of a poorly tuned sloppily wound coil. They probably wont be as nice as some you've seen online, but we all start somewhere.

also... may seem like an obvious question, but are you SURE the NST is running ok? Does it sustain an arc on the sparkgap when there is no MMC hooked up?

-doug

Yongsoo

Tue Jun 05 2007, 03:35AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Spark gap ran fine alone at ~5mm. I sort of rushed while plugging in my camera to the computer and now I am no longer capable of doing so. =[ I stuck my SD card in my wii and am waiting for an e-mail confirmation so I can obtain pictures that way. I'm using 15 942C20P15K-F capacitors 2000vdc with .15mfd. 15 Bleeder resistors that are 10 megaohm 1/2 watt. Alligned in a series. Here are some pictures I took last night. I'm going to cut off the excess ends of the resistors and try again while I wait for e-mail confirmation.

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