Have an Airco 250 AMP AC/DC Heliwelder that is giving me a problem when welding aluminum. The HF is cutting out but it does it sporadically. Doesn't seem to be any rhyme or reason to it. Sometimes it does it immediately and other times it may weld fine for quite awhile without acting up. Current level higher or lower has no effect. Have set the spark gaps a couple of times. Any ideas?
Darrell

gas pressure prob?...just thinking out load here-

Not sure this will help but I had an old miller dialarc 310 with issues like you are having. The relay /contactor that controls the high freq just had dirty contacts so it would energize and pull in but would only pass current randomly.


Good luck.

try cleaning your contacts

gas pressure prob?...just thinking out load here-

I haven't noticed any fluctuation in pressure. Thanks for the out loud thinking.;)

Moe670,
The welder was actually manufactured by Miller and I believe it is actually a Dialarc HF model if not mistaken. I'll check out the contacts. How did you find the problem?
Darrell



Not sure this will help but I had an old miller dialarc 310 with issues like you are having. The relay /contactor that controls the high freq just had dirty contacts so it would energize and pull in but would only pass current randomly.


Good luck.

try cleaning your contacts
okierzr,
I should have posted that I had cleaned the contacts when I set the gaps. Thanks for the input.
Darrell

our miller syncro-wave 210 was doing the same thing, but it fixed itself. I think its an internal ground problem... becuase the welder was sitting next to a metal bench that had a variable speed bench grinder on it....if someone was using the grinder at the lowest speed, and you pressed the pedal on the welder, the grinder would speed up!!! :wtf:

It could be a number of problems polairty switch etc.

It has been a while but i think if you pull the top off and trace the wires from the high freq unit they will go to a contactor/relay. This is assuming we are talking about the same machine. I guess first thing would be to make sure that contatctor is even pulling in. If not maybe there is an issue with the high freq on/high freq start/high freq off switch.

If you could snap and post a picture that would help I would think.

Yep the airco 250 is an orange / s.s. copy of the dial arc 250HF's......
and as for the grinder speed yep HF will do crazy things to surrounding electrical stuff.....
you can get an owners manual that will have wiring etc. from here just select the dialarc 250.......have you tried unplugging it and cleaning the male plug terminals...I know that they will haze over after being plugged in for long periods of time.....
http://www.millerwelds.com/service/ownersmanuals.php

Yep the airco 250 is an orange / s.s. copy of the dial arc 250HF's......
and as for the grinder speed yep HF will do crazy things to surrounding electrical stuff.....
you can get an owners manual that will have wiring etc. from here just select the dialarc 250.......have you tried unplugging it and cleaning the male plug terminals...I know that they will haze over after being plugged in for long periods of time.....
http://www.millerwelds.com/service/ownersmanuals.php

08DMAXMIKE,
I will check out the plug and download the owners manual. The manual will come in handy when I get around to working on it one afternoon this coming week.
Thanks,
Darrell

It has been a while but i think if you pull the top off and trace the wires from the high freq unit they will go to a contactor/relay. This is assuming we are talking about the same machine. I guess first thing would be to make sure that contatctor is even pulling in. If not maybe there is an issue with the high freq on/high freq start/high freq off switch.

If you could snap and post a picture that would help I would think.

moe670,
I will snap a pic later this coming week when I get a chance to look at it again.
thanks,
Darrell

our miller syncro-wave 210 was doing the same thing, but it fixed itself. I think its an internal ground problem... becuase the welder was sitting next to a metal bench that had a variable speed bench grinder on it....if someone was using the grinder at the lowest speed, and you pressed the pedal on the welder, the grinder would speed up!!! :wtf:

DURAtotheMAX,
Good idea to verify the grounds. Will do.
thanks,
Darrell

Have an Airco 250 AMP AC/DC Heliwelder that is giving me a problem when welding aluminum. The HF is cutting out but it does it sporadically. Doesn't seem to be any rhyme or reason to it. Sometimes it does it immediately and other times it may weld fine for quite awhile without acting up. Current level higher or lower has no effect. Have set the spark gaps a couple of times. Any ideas?
Darrell

The HF might be run from a 120 leg in the 240 feed. If so, you could
be loosing internal bonding to the neutral. Check your neutral. Do you
have a 4-conductor plug or a 3-conductor? Do something simple like
run a 15 watt light bulb from the output to the contactor. Put it
someplace where you can see it while welding. Does the
light go out when the HF stops? If so, you have a problem at or before
the contactor. Keep pushing the light power feed back until you
figure out the problem.

I had a red box for a while, and one of the driver circuits for the
gas/water valves stopped working. So I had HF, but flakey
gas. They use opto-isolators for the
driver locking to bypass the noise created by the huge inductive and
RF loads. Sometimes the opto-isolators overheat and fry and you
get wacky behavior. You could have a similar problem. A cold
soldered joint underneath the conformal coating is really hard to
spot.