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Dr. Drone

Sat Jan 13 2007, 02:21AM

Registered Member #290 Joined: Mon Mar 06 2006, 08:24PM
Location:
Posts: 1673

Jrz126

Sat Jan 13 2007, 01:43PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Ok, I moved it up a few inches so the bottom turns are slightly above the primary.

Turns out my crowbar was tripping because I was probing that signal. I also switched over to some shielded cable.

I cranked it up to 480V on the bus and was able to get some 22" sparks to my chicken stick. Unfortunitly, I'm maxed out there, so I need to rework my powersupply

Jrz126

Tue Jan 16 2007, 06:22PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

omg Updatez:
Here's a pic of the 22" sparks. I like the dimly lit flourescent light in the background
http://www.personal.psu.edu/jrz126/images/oltc/22inch.JPG
I built my power supply into a wooden box. I'd say it cleaned up rather nicely.
the old supply
http://www.personal.psu.edu/jrz126/images/oltc/powersupply.JPG
http://www.personal.psu.edu/jrz126/images/oltc/new_supply_insides.JPG
http://www.personal.psu.edu/jrz126/images/oltc/new_supply_installed.JPG
I also replaced that 2 gauge wire with some copper sheet. I added an additional 5.4uF back into the tank circuit to get it back into tune. (I'm running all 120 caps at about 20.4uF now

)
I havent done much testing though. When I first gave it some power after the cap upgrade, something arced from my function generator to ground, so I decided it was time to switch over to a fiber optic trigger and get my expensive equipment out of 'the kill zone' (the FG isn't even mine, I borrowed it from school about 4 months ago). My fiber optic reciever has a minimum operating frequency of about 100kHz, so I need to work some stuff out before i can test it further.

I got the crowbar upgraded to trip out at about 2330 V (it was 23,300V until I realized that my probe was set to 10X). Should I set this lower? my cap bank is rated at 2400V and my brick is 2500V.

Also, I think I had a flashover while testing the fiber optic circuit. I think the choke voltage was charged up to roughtly 300V before the trigger started working. When it did trigger, there was a pretty good sized bang at the base of the coil. It was on the back side of the coil so I couldnt see it. When it does flash over, would it tend to go to my strike rail? or the primary coil? I raised the secondary up so that the bottom turns were slightly above the primary before this happened.

Unfortunitly I am back to school now, so my free time is going to drop drastically

. I'll still try to squeeze some work in here and there. I may even see if I'll be able to incorporate it into a project for my embedded systems class. Though I dont think the prof would let me bring it in to school

Oh yeah, whats the best way to photograph the coil? I'd like to get some nice shots of the smallish purple arcs to air.

Jrz126

Mon Mar 19 2007, 01:37PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Updates...
First off, I have a new pic of me with the coil... here. I really like this pic...I also took a copy of it to my interview with Lincoln Electric. Turns out the VP of sales there is a TC nut as well

I figured out how to use the PCB machine at school. I hope they dont mind if I use it for a few personal projects. (I dont really care if they do

)
here are the PCBs. The two on the left are the SCR controller and the other one is the breakrate generator. They both will use a fiber optic link for remote control. I'll post the schematics once I make a few corrections.

I had it running on the SCR supply on saturday. I noticed the current meter was behaving alittle weird...I was getting a nice steady current (about 3A) until it started arcing. Once I was drawing an arc, the meter would bounce around randomly. sometimes getting up to 12-15A. Is this normal? I'm kinda thinking I'm getting some interference on my SCR controller and misfiring the SCRs?
Also, the output was kinda poor. Running off the 120Vac, I was able to get a max arc of like 15". I tried increasing the breakrate, but there was no increase in output. I'm still in tune too. Any ideas?

Well time for class

edit: Oh yeah I also updated my website with alot of pics and stuff.

Jrz126

Tue Mar 27 2007, 04:35PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Funny updates....

I was playing with the coil last night and was running off the measly 120V line and everything was working just fine. I wanted to try the 220V line since my dad was out of town, there would be little opposition. So I get it all wired up and I flip the big switch that feeds the 220V to the welder. All the lights in the garage immediatly go out, but no asploding of the SCR powersupply, and no tripping of the circuit breakers.
So I figure I popped the fuses in the breaker panel since they react quicker than the CBs. I go to the basement and remove the cover to the panel and realize that there are no fuses anymore. (my dad just upgraded to a 200A service, so no more fuses?). I also noticed that it is just one of the 120V lines that is down.
After about 10 minutes the power came back on its own. So I think I tripped something that was further upstream?

This morning my mom calls me at work and says that half the power is out again. I told her to call the electric company and report it. I guess she was the only one to report a problem. The power came back about 20 minutes after she called. About an hour later, one of the linemen shows up at the house.
About an hour later one of the linemen shows up at our house to take a look. The garage happend to be open, and he noticed the tesla coil (kinda hard to miss). So my mom told him about it. He said that maybe I was loading the line too much or something, I really wish i was there so I could explain it better.

My mom talked with him for about 15-20 minutes, and apparently I went to kindergarden with his son (about 17 years ago

only my mom would remember something like that). He said that he would really like to see the coil running, and he also left me a pair of those super heavy duty insulated gloves that they use for the HV stuff

. I havent seen them yet, but its a pretty sweet freebe for nearly knocking the neighborhood off the grid.

Looks like I have a friend in the electric company

Terry Fritz

Wed Mar 28 2007, 07:46PM

Registered Member #393 Joined: Tue Apr 18 2006, 12:30AM
Location:
Posts: 297

Hi,

You may have a bad connection to one of the phases to your home. It might be blowing open and reconnecting depending on the weather or something. That happens a lot. See if any of the others on the same circuit as you in the neighborhood notice it. Power company breakers will drop "both" phases in all cases and never just one (unless something is really screwed up!). They will also drop power to the whole area. This sure sounds like a problem with the wiring to your house...

my dad just upgraded to a 200A service...

Hmmmmm... Did this problem just happen to start at that exact same time

I would start looking for the problem at that point

If they did not tighten down one of the incoming wires to the new box.... Defective breaker, etc... Call the electrician back and have it rechecked...

Cool! coil you have there too!!! I have not studied it much but it looks great!!

Cheers,

Terry

Jrz126

Thu Mar 29 2007, 03:17PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

You called it Terry. It was the feed at the junction box by the curb. The electric company had to come out 2 more times on tuesday...One guy just diagnosed the problem, then he called another crew to do the repair.

I was able to fire up the coil (off 120V) for the last crew too. They were pretty impressed with it.

Jrz126

Mon Apr 30 2007, 05:17PM

Registered Member #242 Joined: Thu Feb 23 2006, 11:37PM
Location: Erie PA
Posts: 210

Finally finished my senior design project so I had some free time for the coil...

I talked my prof into letting me use it for a final project in my embedded systems course, I had to attempt to audio modulate it. (He wasn't gonna let me do it until I showed him one of Steve Conner's modulated DRSSTC vids). Mine will sound nothing like it though since its just an OLTC. I made sure he was aware of that as well.

I just finished up the controller box for it.

I had some issues with it resetting, so I converted it to run off batteries, but havent had a chance to try it yet.

I was thinking though, there is about 10" wiring between the controls and the PCB in the box, would this extra wire cause some noise issues even though it is in my enclosure?

Steve Ward

Mon Apr 30 2007, 05:36PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

Can you snap a picture of the inside of the box?

Also, was anything else (like the RCA cable) hooked up to the controller when it reset?

And the output is in fact fiber optic cable now, right?

How is your reset pin hooked up?

Where did you get that LCD by the way? Ive been looking around for a decent one and found a few on all electronics, but the cool ones are all EL backlight based (which is slightly annoying needing a little converter in there). Oh, and speaking of LCDs, im wondering if its possibly an EMI leak into the box, and maybe that is the issue? Next time try taping some foil over the screen completely so as to get rid of the large hole the LCD creates. Im guessing there is something that exists to shield displays like this, but is optically pretty transparent (seems so useful that it *must* exist, right?).

Very nice work on that box!

Tom540

Mon Apr 30 2007, 06:19PM

Banned on 3/17/2009.
Registered Member #487 Joined: Sun Jul 09 2006, 01:22AM
Location:
Posts: 617

Mouser and Digikey sell those lcds.

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