Open frame induction motor for cheap, would you go for it?

[Dennis Aspö]

I got a tip for a 2.2 or maybe 2.6kw open frame 3-phase induction motor (I got 3ph so I can run it). It's a really old model, pre-war (that is ww2) most likely, not sure if it works, the man who sounds like an old man over the phone, said his father tested it and it worked then, whenever that might've been... I could get it for scrap money, 10-15 euros I might be willing to offer, he's gonna hook it up and test it so we can see.

I was told it should be a forever kind of motor by the guy who tipped me about it, old solid design, just keep replacing bearings until heat death of universe, assuming the windings aren't broken or burnt.

Thing is I would use it in my workshop which is a dusty enivroment, I'd put it on my jointer/planer. Would you guys put a non sealed motor in a woodworking enviroment?

[Allan Speers]

I got a tip for a 2.2 or maybe 2.6kw open frame 3-phase induction motor (I got 3ph so I can run it). It's a really old model, pre-war (that is ww2) most likely, not sure if it works, the man who sounds like an old man over the phone, said his father tested it and it worked then, whenever that might've been... I could get it for scrap money, 10-15 euros I might be willing to offer, he's gonna hook it up and test it so we can see.

I was told it should be a forever kind of motor by the guy who tipped me about it, old solid design, just keep replacing bearings until heat death of universe, assuming the windings aren't broken or burnt.

Thing is I would use it in my workshop which is a dusty enivroment, I'd put it on my jointer/planer. Would you guys put a non sealed motor in a woodworking enviroment?


For that price, yeah I'd use it. Maybe build a frame around it, covered in gauze or other type of filter material that lets heat escape, then just vacuum it occasionally.

FWIW, my Delta 14" band saw came from the dealer with a 2 HP open frame motor. This was a supposed "upgrade" from the stock 1.5 HP, and at the time it never even dawned on me to check the motor type. Well, it's been run, fairly part-time, for ten years, and everything still seems fine. Very little dust actually gets into the closed chamber when the motor sits.
-----------------------

I always thought it might be possible to add some cooling fins to my motor's housing, either by brazing or simply with JB Weld, then seal the openings and add a large fan at the rear. Since I have no real need, there was no point in trying this, but you could give it a go, for that price. Of course, the motor still wouldn't have intenal circulation vanes, so you'd have to monitor the heat carefully, for a while.

[Frank Pratt]

I'd get it just because it's cool. I love old motors. If it was single phase it would be troublesome because the starting switches get fouled up so easily. But with an open 3 phase motor you'd just have to remember to blow it out pretty regularly.

[Dennis Aspö]

Got it home now, it's incredibly heavy! For a 2.2kw motor it weighs more than my 4kw one, but it spins around beatifully and incredibly silently. I think this will be a fine motor indeed. I want to restore and paint it, I think.
https://farm8.staticflickr.com/7762/17869415171_a174a3c64d_b.jpg

It is open but it does have a fan:
https://farm8.staticflickr.com/7713/17246391474_8554f2b838_b.jpg

https://farm9.staticflickr.com/8825/17682654039_d941ed9bee_b.jpg

[Allan Speers]

That kinda' looks like one of those old replusion-induction motors. If so, then nice score!

[Andy Booth]

Be cautious with any old electrical machine.
The wire insulation is what breaks down and can cause arcing. Wood dust+spark = fire.
Look for cracks in the lead wires.
You might want to have the motor insulation checked using a megger.

Motors this age are over designed and often do run forever.
The nice thing about those old motors is they run cooler at rated power. They are also not as electrically efficient.
Sorry to be such a downer.

[Dennis Aspö]

Don't have a megger but it ran for several minutes without tripping the GFCI which an earlier motor of mine did after 10 seconds every time, when it had bad windings. It really exudes a higher build quality than my more modern sealed motors.

[Dennis Aspö]

That kinda' looks like one of those old replusion-induction motors. If so, then nice score!

I think that is some kinda 1-phase starting switch isn't it? This is just a plain old 3-phase motor.

[Allan Speers]

I think that is some kinda 1-phase starting switch isn't it? This is just a plain old 3-phase motor.


Good question. The "repulsion-start" part only has to do with a ring of brushes that are used to boost the torque of the motor when starting. As the motor reaches maybe 1/2 speed (I forget the exact percentage) that ring lifts away via centrifugal force. I don't THINK this precludes 3-ph motors, but I really don't know.

You'd know instantly if you open it up, which of course you have to anyway, to check the insulation & bearings. (It probably needs to be cleaned & re-greased. - and change "probably" to "almost definitely." )

[Dennis Aspö]

I suppose it doesn't but I can't see a reason for it, a 3ph motor has lots of starting torque, seems to me the point of such a repulsion system is to give a 1ph motor the same starting torque as a 3ph one.

The motor bearings move better than my other more modern motors which I've considered to be in fine shape up until this point. But I will have a basic and careful disassembly and see if I can get some new grease in the bearings.

[Mike Henderson]

That kinda' looks like one of those old replusion-induction motors. If so, then nice score!
If I remember my motor theory correctly, replusion-induction motors have a higher starting torque than a regular induction motor but once they are up to speed, the power is essentially the same as a standard induction motor. Since most of our woodworking machines start unloaded there's no real advantage to a replusion-induction motor in woodworking.

Also, if I remember correctly, replusion-induction motors are single phase motors, not 3-phase motors.

The BIG disadvantage of a replusion-induction motor is the brushes - which wear out and require periodic maintenance. Replusion-induction motors are not used in any modern equipment, to my knowledge.

While many older motors were well built, the materials (such as insulation) available to the designers were not as good as modern materials. Because the insulation was often thicker than modern insulation, the older motors are often physically larger than modern motors. Also, many did not have sealed bearings and require periodic lubrication.

It's hard to beat a good quality modern induction motor.

Mike

[Dennis Aspö]

Some pictures of it taken apart, it was much easier to disassemble than any modern motor I've worked on.

Back lid off, some rust on the rotor:
https://farm9.staticflickr.com/8898/17751880508_3498e04035_b.jpg

Windings are very dusty
https://farm9.staticflickr.com/8847/17319223193_e226bd6465_b.jpg

Look fine from the other side:
https://farm9.staticflickr.com/8781/17752142010_a41d1e24a3_b.jpg

Front lid removed:
https://farm9.staticflickr.com/8785/17940398221_f8d722ddfd_b.jpg

A closer look in between:
https://farm8.staticflickr.com/7660/17939739755_81847a83d2_b.jpg

https://farm8.staticflickr.com/7712/17939744445_22737659f6_b.jpg

A look at the bearing:
https://farm8.staticflickr.com/7711/17319249823_6252d8233e_b.jpg

[Phil Thien]

That is really a neat motor. If that was made today, it would be a "spare no expense" design. Back then, that is how they did things.

If you think of it, post a better pic of the cleaned-up plate.

[Dennis Aspö]

I haven't got a pic but I was able to read the one I got and it says:



ASEA
MOT 3 ~ 50
MKE 12 N 1160467
2.2 kW 3 hk
1420 r/m
380 v Delta 4.8A


Usually more modern motors are 220V delta for norweigan 3-phase or similar, or Star for the usual 380/400V here. Interesting to see one with only the one voltage.

[Ole Anderson]

Nice photos too. You seem to have more than one skill.

[Dennis Aspö]

Thanks, it's a little part of my work to take photos so I have some rudimentary skill. I was going at the parts with an angle grinder and wire brush today:

https://farm9.staticflickr.com/8770/17979206846_4bd80e63ba_b.jpg

https://farm6.staticflickr.com/5342/17979214436_a84a8a856c_b.jpg

Unfortunately I spotted the first real problem with this motor, this is the part that holds the bearing on the fan side, it's broken:
https://farm9.staticflickr.com/8822/17818032570_7752252a12_b.jpg

And on the other side they tried an earlier repair that didn't hold, I believe welding cast iron isn't that reliable:
https://farm8.staticflickr.com/7703/17383076384_37afb3cb62_b.jpg

Not sure what I ought to do now, silver solder it?

[Phil Thien]

How about some pics of the housing ends from the INSIDE?

Are there any schools nearby that teach welding? I think you should consult a professional, to see whether they would advise a repair, or not.

[Dennis Aspö]

There are vocational schools around, I'm not sure what else you can do, repair or throw away, that means a repair is worth attempting to me. My dad used to do welding so he could offer a opinion but that's a trip for tomorrow if so, I was planning to go as I have my bead blasting setup there and bead blast the housing ends and smaller parts.

There's one picture of the other housing posted earlier, the other one looks more or less the same except a lot of crud around the grille, I can go take one but I don't think you'll see much useful at this stage.

[Dennis Aspö]

Continuing with the other parts, no point in holding up.

https://farm8.staticflickr.com/7662/17985268786_d37fdf6cd2_b.jpg

https://farm6.staticflickr.com/5457/17389152624_61d4c23c2b_b.jpg

https://farm9.staticflickr.com/8846/18011765275_6f6e52c806_b.jpg

Pictures for Phil:
https://farm9.staticflickr.com/8822/17824090480_1b1b3bf5a6_b.jpg

https://farm9.staticflickr.com/8774/18008529062_8fbd69e2ca_b.jpg

https://farm8.staticflickr.com/7756/18011750385_31a015d247_b.jpg

I've asked around and cast iron can be welded, the trick is it needs to be evenly preheated, and then cool slowly. I have a shop oven at my dads I can use for that, but unfortunately no suitable welder, only a MIG. Then you need to cool the part slowly, what they used to do in the olden days when cast iron was used much more for machinery was to place the welded part in sawdust and bury it for insulation purposes. Lucky me, sawdust is something I have a lot of.

[Mike Henderson]

You could try brazing it - you wouldn't have to put as much heat into it and a good braze is very strong. There are better welders on the forum than me, but I'd grind out a V shape in the crack and fill it with braze.

Mike

[Dennis Aspö]

Forgot about this thread a while, but the motor was welded and works fine. Don't have any good pictures of it, but here it's mounted in it's new home, unless I find a bigger jointer/planer to put it in:
https://farm4.staticflickr.com/3684/19491119626_bd029ec317_b.jpg

I have to build some better dust collection
https://farm1.staticflickr.com/327/19732231701_3ec90be75b_b.jpg

[Allan Speers]

Pretty great that you were able to save that puppy!

So they're a little inefficient compared to todays motors, it's not like we run them all that much.



I'm curious - was the insultaion 100%? (You did check it, yes?) If not, did you touch it up with shellac, or something else, as some folks have done?

I have an old 1 HP R/I motor that I plan on rebuilding, and I'm looking for ideas. (The Nazi that runs OWWM has banned me from that site, so no help over there. :eek: )

[Dennis Aspö]

I haven't done anything to the insulation or checked it, I think as long as it doesn't trip the GFCI like the last motor I had that was burned out did, then I am OK. NEver heard of using shellac to top it up with, perhaps something to look into as a preventative measure.

I'm turning into the matthias wandel of 3-phase or something, I picked up two more motors over the weekend, a 3 and 2.2kw one for 25 euros each for that price it was hard to not jump on it! Now I have a .75kw, 2.2kw, 3kw and 4kw 3-phase motor, plus one unknown 1-phase motor that's probably .5kw or thereabouts.

http://i.imgur.com/BYwANAk.jpg
The smallest one was only .25kw and I didn't want it.

I never managed to register at OWWM so I've never been there, I've asked at Canadian Woodworking forums earlier though, they have a good vintage section.

[Allan Speers]

I never managed to register at OWWM so I've never been there, I've asked at Canadian Woodworking forums earlier though, they have a good vintage section.

OWWM is a great place. Good people and an insane amount of knowledge. - Just a VERY strange guy who runs things.

Thanks for the tip on CWW - Maybe if I pretend I have mostly vintage Generals, I can sneak in a question about Powermatic. :)

[Justin Meyer]

Some pictures of it taken apart, it was much easier to disassemble than any modern motor I've worked on.

Back lid off, some rust on the rotor:
https://farm9.staticflickr.com/8898/17751880508_3498e04035_b.jpg



Dennis, what treatment did you give to the rotor? Any after pic?