Migatronic changes tone when she's getting tired.

[Gareth J]

I've a migatronic 200 mono, as pictured in the original thread;

What have I bought? migatronic 200 mono...?

I agree 63A would be overkill, go with 32A as long as you have 32A max mcb (and wiring to suit) feeding it.

www.mig-welding.co.uk

It's getting on a bit but still welds nicely.

Been doing some longer runs on heavier plate than I'd normally do recently and was reminded that, after a bit, on higher powers, the noise the machine makes changes drastically. Normally a substantial but healthy sounding clunk of the contactor, followed by a buzz of presumably windings and whatever other gubbins. When, presumably getting hot, the same clunk but the buzz is upgraded to something thats much louder, like I'm suddenly onlining a small sub station.

The change is quite sudden and binary normal - angry.
Still welds ok for some time more but if you keep pushing it, the wirefeed alters and it won't continue doing decent welds.

Definitely seems related to the power that's drawn through it, the higher setting, the less time you have before it changes.

So, is this common/normal? Just an indication that I'm exceeding the duty cycle on it and I need to give it a break?

Or an indication of something else?

 

[the snooper]

Could be resistance changing in the coils as they warm up, check your duty cycle

 

[a111r]

First job I'd do there is strip, inspect and clean up the contactor.
If they're real bad you may have to replace it
When the contacts go bad, they often become very noisy / buzzy.

 

[Gareth J]

First job I'd do there is strip, inspect and clean up the contactor.
If they're real bad you may have to replace it
When the contacts go bad, they often become very noisy / buzzy.

Worth a look, it's overdue a dust out anyway. But I don't think this is noise from the contactor, that sound seems consistent. The grunt seems like a different noise, transformerish

 

[Gareth J]

Could be resistance changing in the coils as they warm up, check your duty cycle

Yea may be. Seems odd the change is so binary but it'd definitely be happening when exceeding duty cycle.

 

[eddie49]

The coils or the laminations in the main transformer or the inductor may be loose. Tighten the bolts that squeeze the cores together, and the mounting bolts to the chassis. Loose winding spools can be fixed with wedges or adhesive.
Does the machine have capacitors? Check them for swelling or leakage.