Bought a new to me Airco Dip/Stick 160 multiprocess welder

[Hondacivic247]

Tested the voltage on each pole of the contactor and got 28.5 roughly on each one, I did tske a screw driver and try to clean up the plates behind the springs to knock some of the crud off

[Hondacivic247]

I tried it out and it's still sparking. I check continuity on the circuit and all seemed fine so I'm really lost, there's some connections on the back side of the selector switch witch I just can't get to safely with the machine running

[H80N]

Still very concerned about leaving those caps "in circuit" while you are chasing this other stuff

if one or more of them is reversed or seeing AC... you MAY be in danger of POPPING them...

those big old ones can go with some force...stink..unravling paper and flying cans...

yours are 1977 date code.... before the "low pressure safety relief" mandates

Newer ones will split before the pressure can build to dangerous levels....

Yours could actually build enough pressure to Explode
and do some possibly LETHAL damage to your person...



Not to mention Deadly Voltages...
I really liked your HVAC guy idea...!!!...... Somebody with electrical training and troubleshooting skills

FOR SAFETY's SAKE..!!!!

[Aeronca41]

Hondacivic247-I too am concerned for your safety. It is very possible one of those caps has completely failed, or something is allowing AC to get to them. If either is the case, you are working very close to a potential bomb as long as the power is on-and for some time after it's off, possibly. There is a good chance of exploding aluminum shards, paper, foil, etc, all of which will be saturated with chemicals you really don't want in an open wound that could result from the exploding cap (or in your eye). While they don't always blow in a dangerous manner, the potential is certainly there. You really need to get a person with good electrical troubleshooting safety knowledge on this-the HVAC guy at work may be a big help. Please don't get hurt. No piece of equipment is worth that--it can spoil your day and perhaps the rest of your life.

[Hondacivic247]

Hopefully the new caps will be here today and I'll get them in this evening

[Aeronca41]

I'd really like to see you disconnect the existing caps and power up the machine and see if your wire feed motor comes back up to speed. If you have a bad diode or some connection issue that is allowing AC onto the caps you could ruin your new ones. Not something you want to have happen. I would sure love to see the power to those caps on an oscilloscope. The sparking at the contactor is likely a symptom rather than the cause of the problem. Something is loading that circuit down in a big way.

[Hondacivic247]

The caps also have a pressure relief valve on the top I noticed the other day, the caps do look perfectly fine . I'm going to unhook the diodes tonight and test them and make sure there not toasted.

[Hondacivic247]

Should I be getting voltage across the contactor relay when the trigger isn't depressed, I just thought of this cause when I tested the voltage it read both sides without the trigger depressed

[Hondacivic247]

Does this look like the same contactor I have, it's used but only 20 bucks. Mine says 240v on the side

[Hondacivic247]

http://m.ebay.com/itm/262462114465

[Hondacivic247]

Is it possible that the sliding metal shunt somehow shorted out against the iron piece that goes over the low and high voltage windings?

[H80N]

The caps also have a pressure relief valve on the top I noticed the other day, the caps do look perfectly fine . I'm going to unhook the diodes tonight and test them and make sure there not toasted.

Really doubt any pressure relief on 1977 vintage beer can Electrolytics......

OF COURSE THEY LOOK FINE...They only look bad AFTER they BLOW...

[Hondacivic247]

The contactor is a 3 pole 240v 30-40 amp but on the inside part were it lists 24v 50-60c the 24v is 24VDC and not AC correct?

[Hondacivic247]

Really doubt any pressure relief on 1977 vintage beer can Electrolytics......

OF COURSE THEY LOOK FINE...They only look bad AFTER they BLOW...

I would say they do, they have a rubber nipple on the top that I was assuming would let go first before the can explodes but maybe that served as a way of filling them?

[Aeronca41]

Sorry-can't tell from the pics about the sliding metal shunt, nor what you mean about the voltage readings on the contactor (which I still do not believe has anything to do with the problem you're chasing). Don't understand what "across the contactor" means. And all 3 poles have to read the same voltage-they are all connected in parallel by the big copper "finger" busses on the line and load sides. They parallel the 3 contacts to get enough current carrying capability.