Miller 250DX power issue

[Zapperman]

I bought this thing used and just now had time to use it. I wanna say it's a mid 2000 year model. I used it a couple times playing around welding SS with it and it did fine.

Next day I did the same thing but had a couple phone calls come in and let it idle for about an hour. I came back into the shop to find it shut off but looking further, my circuit breaker had tripped. While looking in the panel I smelled something so I took the cover off and found the wires to the welder breaker hot and the breaker along with the service breaker and feed wires as well.

After a while I turned my welder back on and checked my panel wires. The wires from the welder plug in to the breaker are vibrating and heating up with the welder just running no load.

What could be my issue with this?

[Zapperman]

I forgot to say that I have a 100A service to my shop and a 60A breaker for the welder. We welded aluminum with my buddy's older Miller 250 tig welder with no power feed issues and my welder did fine for two days until this started

[griff01]

I bought this thing used and just now had time to use it. I wanna say it's a mid 2000 year model. I used it a couple times playing around welding SS with it and it did fine.

Next day I did the same thing but had a couple phone calls come in and let it idle for about an hour. I came back into the shop to find it shut off but looking further, my circuit breaker had tripped. While looking in the panel I smelled something so I took the cover off and found the wires to the welder breaker hot and the breaker along with the service breaker and feed wires as well.

After a while I turned my welder back on and checked my panel wires. The wires from the welder plug in to the breaker are vibrating and heating up with the welder just running no load.

What could be my issue with this?

You may have a Power Factor correction kit (capacitors) installed. It actually pulls more amps at idle than in use.

Griff

[H80N]

Serial Number..??? PLS....

[Zapperman]

You may have a Power Factor correction kit (capacitors) installed. It actually pulls more amps at idle than in use.

Griff

Yes I believe it does have this. Looks like 4 beer can sized capacitors inside the unit.

[Zapperman]

serial number..??? Pls....

lc530538

[H80N]

lc530538

TNX...

Built in the second half of 2003

Here is the link to download the correct manual version

https://www.millerwelds.com/files/owners-manuals/O359N_MIL.pdf

[Zapperman]

TNX...

Built in the second half of 2003

Here is the link to download the correct manual version

https://www.millerwelds.com/files/owners-manuals/O359N_MIL.pdf

Thanks but I already have the manual and I didn't see my issue in the trouble shooting section

[cruizer]

parent board and IGBTS is likely smoked

[griff01]

Yes I believe it does have this. Looks like 4 beer can sized capacitors inside the unit.

Yep. That's the PF correction kit.
I see also that Cruizer has more info for you.

Griff

[Zapperman]

Yep. That's the PF correction kit.
I see also that Cruizer has more info for you.

Griff

This was the issue. At idle it was drawing 60A. Unplugged them and it's drawing around a couple amps at idle.

[griff01]

This was the issue. At idle it was drawing 60A. Unplugged them and it's drawing around a couple amps at idle.

Thanks for the feedback. Glad you got it figured out!
And just so you know, these aren't mentioned in the manual for the machine. The wiring diagram comes as a separate sheet with the capacitor kit.

Griff

[ryanjones2150]

What's the purpose of the power factor doofloppy?

[H80N]

What's the purpose of the power factor doofloppy?

It makes the power wattmeter think it is drawing less power under load

https://en.wikipedia.org/wiki/Power_factor

[griff01]

What's the purpose of the power factor doofloppy?

Not any benefit for a home or small shop. In a large shop (really large) the power companies penalize them on their electricity bill if their PowerFactor gets out of whack. If I remember correctly, they want the PF just below "1". If it gets to or over 1 they are penalized.
The PF (capacitor kit) helps to alleviate this.

Griff