Repair lathe motor?

[R.G.]

Sorry about the "good" and "U.S. made" thing, that was really a poor choice of phrasing on my part. I know there are some beautiful motors of foreign manufacture and that "U.S made" is not the "end all" of everything. On the other hand, I do prefer to buy American made goods as longs as they are of equal or superior quality and are available at a competitive price. The quality of the component is the major deciding factor, not necessarily where it is made.

No problem on that - I agree with you totally. I just wanted to be sure you were considering all possible sources for your motor, best deal (i.e. Quality/$) for you.

About the only reason I was tending towards AC single phase is cost. While the 3-phase and DC motors might not be all that much more expensive than an AC single phase (I don't really know as I haven't tried to price anything as of yet - so guessing here.) if I were to go with DC or AC 3-phase I would need other equipment to be able to use those motors.

That's very rational. Single phase AC, especially capacitor-start and capacitor-run are kind of where the whole world has settled if there is no overriding other factor. Overriding factors might be total power (better with 3 phase), smoothness of power (better with 3P and DC), need for variable speed (very, very hard to do with single phase), perhaps others.

There are more 1P motors around because there are more of them made. On the other hand, 3P motors in an equal power rating are much cheaper to buy used, because no one wants to cope with the problems of getting 3P power to them, as you noticed.

It is my understanding that a DC motor also needs some kind of controller as well. Since I don't have 3-phase in my shop/garage (even though I'm only about 50' from the nearest transformer) I would either need to have it run at my expense or purchase a VFD or converter. How do these real stack up against each other cost wise?

IMHO, 3P is not a good idea unless you already have 3P wiring or intend to go to a VFD anyway. VFDs can be had for about $100-$150 if you look hard - I know of some on ebay, but haven't yet bought one. I *do* have a 1/2 HP 3P motor I bought for my lathe, intending to go variable speed. It cost me $30.

DC is about the same price as new 1P or 3P in similar sizes; you're talking about $180-$300 depending. DC does need a speed controller. This is available as the KBPC-19PM for about $40-50, or more expensive if you want.

These are just my off-the-cuff opinions, but I have been looking at this issue for a while.

I need to measure the current motor shaft to see if I can use the same pulley. It might not hurt to get measure the bolt pattern, clearances, etc. either. :thinking: Always seem to need "more information".

There's never enough info available. Measuring the length, diameter, weight, shaft size and length, etc. would be a real step forward to getting a good replacement. As noted, there may be one in a junk pile...

Oh - forgot. Ventilation style. What's the cooling air like where that motor lives? Does it have dust, perhaps conductive dust, coming down on it from the lathe? Swarf-bearing oil drops? Electric motors come in some standardized ventilation styles.

Air-over is bad for machine tools. That term means that it has to have cooling air coming over it all the time. This is great for a blower or fan motor, deadly for motors without fans.

"Drip proof" means that the top surface is sealed up, and relatively immune to specifically drips from one direction. Not a good idea if the cooling air contains dusty contaminants.

TEFC = Totally Enclosed Fan Cooled; these have a built in fan that blows air over the motor, but are otherwise enclosed.

TENV = Totally Enclosed Non-Ventilated; no openings for contamination to enter.

I would want one of the last two for my lathe.

 

[ScrapMetal]

"spare motor pile" - I like that. Everyone needs one of those.

Nice run-down of options there R.G. gives me a lot more to work with. You brought up, in a round a bout way, one of the frustrations with looking for something like this on the 'bay. For the most part, and especially with used motors, some of the necessary information is not to be had. They don't usually post the information and just try asking a vendor if the motor is drip-proof or the kind of ventilation it uses. Most of them have no idea of what exactly they're trying to sell. - Sorry, rant over. -

Again, thanks guys. I'll see if I can't get some of that allusive "info" tomorrow.

-Ron

 

[R.G.]

I always assume the seller is clueless or worse on ebay. So I take the approach that (1) if it doesn't have a model number sufficient for me to go look up exactly what it is, I don't even read the description any more and (2) I go look up the manufacturer's data sheet to see if it does what I want. Google is our friend.

I'm sure I miss a lot of good deals that way, but I also don't wind up with such a big pile of stuff that maybe I'll find a use for someday.

 

[ScrapMetal]

I know a little more today. The shaft is 3/4" and keyed for the pulley. The bolts pattern along the axis parallel to the shaft measures 5". Width or perpendicular to the shaft is over 6" but variable as the mount has long slots. As we could see on the pic of the motor tag RPM is 1780 and the motor type is SCA. Anyone able to tell me what "SCA" means?

I'll be doing some searching/reading on the internet for motors tonight.

-Ron

 

[ScrapMetal]

Nice deal. You have basically a 4-speed lathe then (whether you use it or not). Very "uptown". Did you have troubles with mounting and thus the plywood base?

Thanks,

-Ron

 

[R.G.]

So - what happened? Does it work? New motor? Refurbed motor?

Inquiring minds want to know.

 

[ScrapMetal]

{Lost posts}

I've been sidetracked by a number of other higher priority "projects" but I should be returning to this one shortly. I've done quite a bit of research on motors and narrowed down the choices a bit. For ease of installation I am looking for something in a 145T configuration.

As was mentioned (and now lost) I've looked at Surplus Supply quite a bit. Turns out they are based in Lincoln, NE which is only about a 45 minute drive from where I live - bonus!

Despite other projects I do need to just "bite the bullet" and get something ordered.

-Ron

 

[martik777]

Those old GE motors are almost indestructible - hope you can fix it.

Looking at your sig, I see you have at least 3 temporarily suitable (free) motors right on your shop: The shaper, 4x6 bandsaw and drillpress, probably less HP but rpm should be about the same.

 

[ScrapMetal]

Those old GE motors are almost indestructible - hope you can fix it.

Looking at your sig, I see you have at least 3 temporarily suitable (free) motors right on your shop: The shaper, 4x6 bandsaw and drillpress, probably less HP but rpm should be about the same.

I hadn't really considered that. Interesting to say the least and a great tip if I get myself in to an "emergency" - motor down type situation.

Make that only two though. The motor on the shaper is huge in comparison. It's case alone is about 14" in diameter. It would take some serious re-engineering of the lathe/drive to fit that puppy in there.

Thanks,

-Ron