[sschefer]

I asked this over in the General area also but thought it was probably pretty well confined to A/C tig welders and this might be a better place to post it. If that's not a good thing to do please let me know and I won't do it again... Dang newbies anyway....


I just got my first TIG Welder. It's a new Lincoln Precision TIG 225 with all the bells and whistle including a add on water cooled torch. Yep, I'm a newbie to TIG but I've been gas, stick and MIG welding as a hobbyist for around 30 years.. And yes, I'm an old fart to boot. I've laid down about 10 practice welds and like what I'm seeing and that theory about learning gas, ... yep, it sure helps.

Anyway, I've got a 50 amp 220v circuit in the shop and last weekend while welding I heard the doorbell ring. I went to check and no one was at the door. On the way back to the shop I noticed the sprinklers had been on. I fired up the torch again and heard both the doorbell ringing and saw the sprinklers come on. It doesn't do it in DCEN, only in A/C. I'm speculating that it's the HF with the A/C and the wire is radiating it all over the wiring on it's way to ground.

The subpanel feeds the lights, pool filter pumps and one 20amp duplex outlet. Only the shop lights were on at the time. The pool pumps are frame grounded to a grounding rod that is separate from the rest of the wiring, (until it hits earth). The welder is grounded to the subpanel at the ground bus bar and the neutrals are isolated. Theres an old drill press that was plugged in to the duplex outlet at the time and it's about 5 feet from the welder. My welding table is not grounded and is on rubber casters.

I'm thinking I should run a separate ground from the ground rod that the pool pumps are on and tie the welder and the table into it via a buss bar.

I've got a pretty solid electrical/electronics background so when the weird unexpected stuff happens I ask questions first and try to avoid the easter egg hunts. Any thoughts?

Thanks

Steve Schefer
Santa Rosa, CA.

[kermdawg]

Thats wild man. I take it all your shop is on the same 50 amp circuit? I got my welder on a -dedicated- 50 amp breaker with 8 guage wire(its about a 100 foot run). I dont know if its the HF but if your gonna do some serious welding you might think about putting your welder on a seperate breaker. I know 50 amp is overkill but better safe than sorry right? I'm not a licensed electrician or anything but I believe I remember seeing a 30 or a 40 amp breaker will do ya on the stuff I was readin.

[ogorir]

I'd ground your welding table, first off. that should take care of it, as right now, that HF high voltage is trying to find a place to land and it's just traveling down the welder's ground plug into the wall.

you might also put some ferrite beads on the power leads to the sprinkler control unit. there are a variety of slip-on ones that clip into place, I'm sure you've seen 'em on all sorts of things. that should kill the HF before it gets into the control box.

you might need to add a separate subpanel and grounds if that doesn't solve it, or at least another breaker. 50A certainly isnt overkill if you're welding near max capacity. figure 35v at the torch at 225A, and you're looking at roughly 35A multiplied by whatever the efficency of that welder is. I'd guess something like 65 or 70% as it's a transformer based welder, so worst case (65% efficent) you're looking at 53.8A at the wall.

[sschefer]

Thanks for the reply's it is pretty wild. The RF should be going to ground like was mentioned and I'm pretty sure it's just backfeeding. After all a properly configured sub panel is a back fed circuit. If I isolate the welder ground from the panel it might just take care of it. I can always just unplug the sprinklers but I can't imagine driving everybody nuts with the door bell ringing this winter when I'm building my new 21 ft aluminum boat... I'd be dead meat...

Thanks again.. If anybody else has had this problem I sure would like to hear about it.

[sschefer]

I found a couple of solutions. The first somewhat coincides with Jody's spark gap setting issue and a problem that the previous owner complained about. The previous owner said that he'd talked to several Lincoln owners about hard starts on A/C and interference. He said that all the Lincoln TIG welders had the same issue. He was absolutely correct in his statement but at the same time, reading the Manual would have led him to the cure.

The gap on my machine wasn't all that far off but it was enough and bringing into minimum specs cured the occasional hard starts and stopped the doorbells from ringing. The sprinklers still came on but it was just momentarily so I knew I was on the right track chasing a HF interference problem and not a ground problem.

I wrapped the sprinkler wiring the full length in tinfoil and clamped the foil to a nearby water line. That worked and stopped the problem completely. I'll pickup some EMT at Home Depot and pull the sprinkler wire through that and the old phone line that's still hooked up. That'll should clear up the phone noise also.

[sschefer]

Just wanted to update this since I've re-wired the entire shop/garage to code.

The problem with the sprinkler system comming on persisted so I removed the earth wire from welding table. My table is on locking rubber casters so without the additional earth connection it is completely isolated.

Two things happened when I did this. First, the sprinklers still came on and second, my welds improved (both mig and tig) and my tungstens stayed sharp longer.

Since the doorbells had stopped ringing, the phone interference went away and the flourescent lights stopped flashing with the re-wire, I was able to isolate the sprinkler problem to being a polarity problem at the control. I checked polarity on all the valves, found the one wired backwards and the problem is now corrected.

When welding on some 3/16 mild steel scrap with the earth (ground) on the table I had to turn up the wire feed speed to stop my MIG from spitting and with TIG the tungstens were eroding (not balling) and it didn't matter if they were pure or 2% thoriated.

I won't dare go as far as to say this is the way everyone should do it. I'm simply saying that this is what works best in my shop. From and electrical engineering standpoint, the ground shouldn't effect the weld but my Linconln 225 and my Miller 212 are telling me different.

[jakeru]

I noticed that sometimes when I use the HF start in my TIG, (especially if there is something wrong with my work ground and the main current doesn't hit right away,) it does something funny with my garage door opener. It has made the door opener's light blink on and off, and the unit no longer will open and close the door until I reset the power to it. (At least the door is not opening/closing from the TIG arc!)