Airco Migit spool gun issues

[knied1]

Hi all,

I just purchased an Airco welder

Aircomatic, Miget Model 2DCR-S224

as soon as I plug the machine in before I even turn the welder power on the drive roller spool gun starts rotating. if I pull the trigger there is no change, and if I turn the wire feed speed the roller does increase , and decrease speed.

has anyone seen this before, and if so where should I start looking to fix this issue?


Thanks for any help you can give.


Sincerely,

[Aeronca41]

This happens with the welder turned off? Sounds strange; please confirm that is really happening. I'm not at all familiar with the product but something like this would generally be due to a bad switch or a shorted wire. I'd first unplug the welder and disconnect one of the wires from the switch. Power back up and see if it's still running. If it stops, likely a bad switch. To verify, with one of the wires still off, and welder unplugged again, set your meter on a low "ohms" scale and connect a lead to each side of the switch. Should read "OL" or a very high ohms value, and should go to zero when you close the switch. If the switch checks good, you must have a short somewhere, which may be a bit harder to find. Would need a diagram and some pix.

[knied1]

yes it is with the welder off.....was kinda surprised that power was going to the spool gun without the welder power on.

im at work right now, and cant take pics.... bi I will include some later

[Aeronca41]

That is strange. Please post your ser no. so we can see if a manual is available. Pix of the welder and spoolgun would be good. Kinda shooting in the dark on this one. Without a diagram, this is going to be well-nigh impossible to troubleshoot long distance unless someone who knows the machine responds. What's your location? There are a lot of really knowledgeable guys on this forum who may be able to help.

[knied1]

welder serial number is P346605. I do not believe the serial number is still on the spool gun

I do have the 2 attached wiring diagrams for the unit

[Meltedmetal]

Verify that the input wiring is done correctly.

[Aeronca41]

Both the switch and input wiring need to be checked--good input. Next, need to find out which of the diagrams represents your machine--with or without stabilizer? One really simple thing to check first, though--is there a switch on the front panel that has one position labeled remote? If so, try changing its position and see what happens. Otherwise, if you have the one without stabilizer, either the W contactor is stuck on, or is being energized to the on state by some other issue. If W is energized all the time, or the contacts are stuck, it would cause exactly what you're seeing. If you have the stabilizer, contactor CR1 could be stuck on or always energized by a problem in the switch or wiring somewhere.

What is your level of knowledge of things electrical and electrical safety? Can you locate the referenced contactors in the machine? without a manual with photos, its pretty hard to provide guidance.

[knied1]

I have the machine without the stabilizer.....I will look at the W contactor and start tracing from there.
the other thing I just thought about was is the jog button shorted out.....and maybe start by disconnecting contact 20 on the panel


Thanks alot

[Aeronca41]

Sounds like you know your way around a bit. Good luck. Let is know when you have it fixed! :-)

[knied1]

Well I think its the speed controller in the gun.....on the terminal trip in the welder and in the gun if I disconnect terminals 13,15,16 and 23 the drive wheels stops (disconnecting individually) and if I disconnect 14 the drive wheel speeds up....also the speed controller gets hot.....granted it could be getting hot from something before it in the circuit shorting out.....but I don't see anything that could be causing that.....do you see anything I could be missing.


Thanks again

[duaneb55]

What did you find when you checked the weld contactor "W"?

My money would be on stuck contacts as Aeronca41 stated which is - unless someone miswired the unit - is the only way the spool gun can get power with the unit just plugged in and not "ON". You would also have voltage at the weld output studs.

[Aeronca41]

Agree that disconnecting any of the listed wires would stop the motor, but the question is why is there power to those wires when there shouldn't be? What you're dealing with there is treating the effect, not the cause. The problem is very very likely somewhere else-contactor W or something feeding it has to be the problem. W is the only possible source of power with the welder off, as Duane said.

[knied1]

Luckily all of the wires both in the welder and in the gun still had their contact numbers on them.....so I was able to check the wiring, and yes it is all connected correctly.

when checking contactor "w" should I simply be checking for continuity, and that there is none?

[knied1]

and then next question is
the spare parts list show Cutler Hammer and Furnas part numbers, but I am not able to find these parts online by their part numbers
Cutler Hammer 34-665 and Furnas 34-740. see attached.


Does anyone know where I can cross reference these to a newer part number?

[Aeronca41]

Luckily all of the wires both in the welder and in the gun still had their contact numbers on them.....so I was able to check the wiring, and yes it is all connected correctly.

when checking contactor "w" should I simply be checking for continuity, and that there is none?

Correct. With the welder unplugged, check for continuity across each of the two pairs of contacts. Should be an open circuit-no continuity. Even though the welder is unplugged, be sure the power switch is off because it looks like you might get a reading back through the the coils of the transformer if it's on; no need to add a confusion factor. Depending on the design of the W contactor, you may be able to see if the contacts are stuck, but the continuity check is best. If it's bad, see if there is a vendor part number on the contactor, or mark connections well, pull it out, and take it to a local electrical supply house - they should be able to find a match. Take your wiring diagram along.