MillerMatic 212 turns itself off

[aPoundFoolish]

Hello, I purchased a used Millermatic 212 AutoSet that seems to have a problem with my 240v power.

I took the machine to a Miller Dealer/Repair shop near Chicago who plugged the machine in and said it worked just fine. Once back in my garage, it won't work. I plug the machine in, flip the switch and both lights on the front of the welder come on for a second before the machine shuts itself down.

I had an electrician out to check the outlet and he said it was wired correctly. He did note that my voltage was a bit high at 247-248v. In the welder's manual it calls for 230v and the metal jumper inside the machine is set for 230v.

Could the over voltage at the receptacle be causing the welder to shut itself down?

Any advice is appreciated!~

[ryanjones2150]

I would start at the panel and re-do that circuit. Then you'll have no doubts as to whether or not it's wires correctly.

I would expect to see somewhere around 244 volts.

[aPoundFoolish]

Does anyone think I could use a Variac to drop the voltage down from 250v to 230v?

Tearing out the circuit and redoing it is a possibility, but a challenge because the space is rented.

I had the electrician check the 240v across the hots, 120v between hot/ground, and also checked for any voltage drop when the machine starts. All rock solid. Are there any other electrical issues I can test for on the line? Frequency?

[ryanjones2150]

All I can think is if you have higher voltage than you should then you need to call the power company to check your service drop and transformer.

I have never heard of anyone running a welding machine on a variac. 230 just means a double pole, 30amp. It is about 244v anyway. Check it yourself with a DMM. Check the panel, the mains, at the breaker and then at the socket.

But make sure you have the correct plug. Take the socket apart and make sure it's wired correctly. Your machine appears to be fine, so it's your power that is the problem.

Start at the main lugs on the panel and work towards the socket.

[griff01]

Hello, I purchased a used Millermatic 212 AutoSet that seems to have a problem with my 240v power.

I took the machine to a Miller Dealer/Repair shop near Chicago who plugged the machine in and said it worked just fine. Once back in my garage, it won't work. I plug the machine in, flip the switch and both lights on the front of the welder come on for a second before the machine shuts itself down.

I had an electrician out to check the outlet and he said it was wired correctly. He did note that my voltage was a bit high at 247-248v. In the welder's manual it calls for 230v and the metal jumper inside the machine is set for 230v.

Could the over voltage at the receptacle be causing the welder to shut itself down?

Any advice is appreciated!~

247-248 volts is not causing your problem..
Griff

[aPoundFoolish]

OK, so no VARIAC, the 247v is not a problem.

My plug is the older NEMA 10-50 3-prong plug (the "scream mask" outlet, as some people call it). My hots are getting 247v and the third prong is wired to the ground bus at the panel. I get ~120v when I measure between either hot and the ground. I believe that means the outlet is wired correctly for that type of outlet?

Is it possible that everything will check out on the DMM, but the outlet is still bad somehow?

I'll check all of the connections and make sure they are in place and tight.

Does anyone think there is any diagnostic significance to both of the lights (the yellow overtemp light and the blue light next to the wire feed dial) coming on and then shutting off when the machine powers down? I was told by the Miller tech that neither light should come on unless there is a problem but Im unsure if its trying to tell me something...

[ryanjones2150]

Go between the hots and your should get 240.

You should have a neutral on that and not a ground. You need two hots and a neutral.

Open that socket up and look.

[Meltedmetal]

I disagree, no neutral on 2 wire 240v. The ground is the safety to trip the breaker and should not normally carry current in newer wiring.

---Meltedmetal

My mistake Ryan is correct on the 10-50 I'm thinking of the 6-50. Is that the original plug on the machine?

[aPoundFoolish]

It looks like the old style 10-50 calls for Hot/Hot/Neutral, while the more modern 6-50 calls for Hot/Hot/Ground.

Could confusing the Ground/Neutral cause this issue?

Does the machine check for this/does it know the difference?

[ryanjones2150]

Man, all you're giving us is your machine doesn't work and some guy told you your wires are good. You need to bust that thing open and check.

Years ago I had a machine someone gave me, I plugged it in at his house, worked fine. Plugged it in at my house, barely a spark.

Cracked open the machine, one of the hots and the neutrals were swapped. They were swapped at his house too, at least the colors were.

Open it up and take a look.

[aPoundFoolish]

Open it up and take a look.

OK, I'll trace the cord into the welder to make sure all 3 wires connect to where they should internally.

Since it worked fine at the dealer I was ready to rule out any issue with the welder itself.

[Willvis]

Strange that the 10-50 has a neutral but no ground? Isnt that sortof a safety issue not having a ground? Anyways I dont think the machine knows or cares about that. Neutral is tied to ground in the pannel anyways. From a pure electrical view all you need is the 2 hots. The neutral and or ground could be disconected and a welding machine will work. I also dont think 247 volts is too high, Im pretty sure mine reads around there some times. You could check the frequency but thats set at the power plant so I dont see how that could be wrong. Are you sure it worked fine at the dealer lol?

[Willvis]

The spec sheet on that machine says it keeps the power constant at +/- 10% change in input power. 10% of 230v is 23v so the machine should have no problem at all even at 253v. Are you using some kindof pigtail adapter? That 10-50 didnt come standard on the machine so you either changed the plug or are using an adapter. Me thinks you got a hot and neutral crossed and your only inputing 120 into the machine.

[ryanjones2150]

I don't think it would work well if you disconnected the neutral. You must return the power somehow.

[Willvis]

Lots of stuff uses only 2 hots. My welding outlets in my shop only have two hot wires run in them. I used emt (conduit) and it acts as the "ground" and its only there for safety.