Miller Thunderbolt repair parts...or other solutions

skylarkguy · May 6, 2014

So the cooling fan in my old Miller thunderbolt has been making noise for a long time. I finally took it apart to investigate how bad the cooling fan motor was...it is pretty much shot. I took the motor to a local repair guy and he can't/won't fix it. Apparently the bearing are likely unavailable. The local welding supply house wants $123.00 for a new motor, ($8 for the fan if necessary), miller 4 less wants $100. No luck on e-bay. So I put the question to the welding guru's here. Anybody have a sleeper venue for miller parts-I'd even take a good used one?

My related question is can i finish the project by running the machine with the case open and a box fan pointing at it? If it overheats what happens-I assume it pops a breaker- but what other issues can arise? Thanks.

Scooby074 · May 6, 2014

What voltage is the fan?

Ive found some surplus mainframe 120v fans for cheap that would make impressive welder cooling fans (think large PC fan). Check your local surplus store.

skylarkguy · May 6, 2014

That is kinda the rub it is 230v .
The other specs are 50/60 htz. 3000 rpm with a .181 inch shaft. At least that's what the book says.

Fifelaker · May 6, 2014

I found one that was a close match for an old Crafstman at Grainger. LWS and Sears wanted upwards of $75 Grainger was like $18 make sure the mounting holes, shaft and voltage are the same. The shaft was too long on the new one but a couple of minutes with a sawzall and all was good.

CalG · May 6, 2014

230 v muffin fans are cheap enough. Search e-brat or try Electronic Components and Accessories | MPJA.COM

For casual work, I would just run it , If I was working something needing full duty cycle, I'ld put the floor fan to it.
Those little fans at the bottom of the box aren't much.

I just cleaned out my T-bolt and lubed the fan a couple week ago. At least it starts up without the skeetching now ;-)

ps, put two 120v muffin fans in series that will do the trick as well. $15 and a mount....

Stimw · May 6, 2014

Check with Grainger, they carry a lot of generic motors for everything.

smyrna5 · May 6, 2014

Mine ran for a long time without the fan hooked up, but I don't tend to weld very long at a time. That may be why one of my diodes burned out, beforer I got the machine. When I finally replaced the diode, I also wired the fan back up. I agree with CalG, you could simply put two 120 v fans in wired in series. Make sure they are identical, and they will both have the same voltage drop

Scooby074 · May 6, 2014

skylarkguy said:
That is kinda the rub it is 230v .
The other specs are 50/60 htz. 3000 rpm with a .181 inch shaft. At least that's what the book says.

Just search Google for a 240v axial fan. Ebay alone will have hundreds of hits. You should be back in business for under $30.

skylarkguy · May 7, 2014

Thanks everyone. I got this 220V 230V 240 V AC Cooling Fan 120mm x 38mm | eBay

A bit of mounting fabrication and I should be up and running, next week.