My motor run stops & run. Is that the sign of the motor going or is it the control board?

 

The motor is just a 12v.
Disconnect it from the control board and try powering it up with 12v.
You may have bad solder joints or a broken trace on the board.

 

thanks I will give that a try.

 

I took it wire feed assembly apart tonight & I tested the motor & it runs fast & smooth. I even tried stopping it with my fingers & it turns good without stopping. I tried turn the gears by hand & I could feel a stop sticking. I checked all gears & all look good. The outside bushing looks to be wore a bit. Can you buy bearing as a replacement? The size is:

0.2345 - shaft diameter

0.2465 - bushing thickness

0.3945 - bushing o.d.

I should mention when I put the motor back in the plastic housing & ran it with the trigger it didn't feel as smooth as with the car battery but it did good under load with my finger test.

 

The motor will usually run rough when you run it and it's not welding.
The open circuit voltage makes the motor voltage limit circuit cut in and out.

You might be able to find a bearing or bushing of that size.
The whole motor drive unit used to be about $12 from HF.
You could just get a new one and lube it up and keep the old one for spare.

If you like experimenting, you can put a 100-200uf capacitor across the motor leads, just get the polarity right.
It makes them run a little slower and smoother.http://weldingweb.com/showpost.php?p=329162&postcount=48

 

Radio Shack only has a 220uf would that work?

 

220uf would be fine,it is the closest standard size to 200uf.
Most electronic components are lucky to be within 20% anyway.

 

I found some bushings from an RC-10 Stealth transmission that are the same diameter 0.294 but the i.d. is 0.31 smaller. I'm thinking if I could get bearings I might cut the wire feed drive shaft down.

 

The things are all metric,probably 6X10mm bushing.

 

Blue your are right they are 6mm x 10mm. I got some HPI B045 rc radio control bearings & I machined some spacers up to make up for the thickness & seems to runs more freely now. I added the cap too & it seems to smooth out a bit.

 

If the motor's running good now, you might also check the wire feed liner for smoothness.
It doesn't take much of a motor to slide a little piece of wire to the work,if everything is right.
Having the wire stop and start is usually a binding spot in the feed wire path, a badly wound roll of wire, or even running the feed rollers tension too tight.

 

I did notice when replacing the bushing out for the bearings the outer bushing along with the shaft itself looked like it was dropped or something because they was a pretty big burr/nick on the end of the shaft.

I noticed no my motor there is a red dot which I thought indicated positive polarity but after tracing the wire back it goes to the negative side of the rectifier. I know if you turn the endbell 180 the motor will run in reverse but I'm not sure if reversing the polarity would have the same affect? I know on my rc motors it don't. I strange they would mark it that way.

 

It just means that from the factory it will run in a certain direction with that polarity.
They don't seem to build them with a preferred direction of rotation,like a tuned motor would have.

 

Got ya! I just finished up installing the fan you did & I must say that is blasting the inside with fresh air now! WOW :drinkup:

I did a pass & it seemed to work much better but I'm not sure if I have enough tension on the wire feed (I have 3 threads showing)? I have the speed set on 2 & tried 3 & the cord is straight but it seems like it's hanging up somewhere & then bang it works good & it does this now & then. I can heard the wire feed running & the spool is set with the wing nut right at the edge of the threads & if I put the slightest bend in the cord it won't feed the wire. :realmad:

 

If the wire feed liner is bad, more tension will just make the feeding problems worse.
If things are right, the feed mechanism just has to slide a little steel wire 6ft through a tube.
The only real friction that should exist , is enough tension on the wire reel to keep it from unspooling.
You might consider putting in a new steel liner, the plastic ones can get crimped spots in them from being bent too sharply.
There also is a short piece of skinny liner in the swan neck on the torch.

 

Will any kind of steel liner work from any mig?

 

I used one from a Miller Cricket.

A liner from a Tweco Minimig might work
The whole liner is about 15ft long,but if cut to size for the 151 would give you two pieces.
I had to use a Dremal to cut it to length,and a points file to deburr it
The liner is a snug fit into the the odd coupler on the torch end, and needs a piece or two of heat shrink tubing on the wire feed end to be snug in the clamp.

 

Ok thanks for all your help! It's much appreciated!

 

I was told the cricket was discontinued 20 years ago & I can't find anyone that carries the Tweco Minimig how can I be sure that it'll work? I don't wanna buy & then have it not fit.

 

I think all of the .030-.035 liners that I checked had the same outside dimensions.
Maybe you could use a micrometer on one before you buy it.
Various people have used a Tweco style liner made by Radnor,usually in the $9-$12 range.
The only really important dimension for the liner, is the outside of the liner.
You could start a thread on what brand and size liner other people have used.

 

ok thanks!