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Unimat DB200 Dutch Motor Diagram #db200

 

Hi, new to this forum and have a very old cast iron DB200 I am restoring that was given to me. ?The only problem is that everything is in parts, including the motor. ?I am close to being done with the entire lathe restoration with exception of the motor. ?I am looking for a good breakdown/diagram of this early Dutch induction motor. ?Any help is appreciated!
 

Hello, and welcome!

I am, I believe, one of only a few members who have the induction motor. Being an induction type, there are very few parts. The field, rotor, fan, capacitor, and maybe some thrust washers.

What would you like to know?

Martin P.

-----Original Message-----


Hi, new to this forum and have a very old cast iron DB200 I am restoring that was given to me. ?The only problem is that everything is in parts, including the motor. ?I am close to being done with the entire lathe restoration with exception of the motor. ?I am looking for a good breakdown/diagram of this early Dutch induction motor. ?Any help is appreciated!
 

Thank you for getting back with me Martin. ?I need to know how to place the thrust washers on the armature. ?I only have 2 of them and not sure if one goes on each end, or due to electric theory and the right hand rule do 2 go on the same end to absorb the torque of the motor starting. ?I haven’t been able to find any literature on this little motor.?


thanks for your help
 

To be honest, I only know what I know about motors from reading online and years of tinkering. I am an engineer, but not electrical.

Anyway, I think at some point I also needed to know where the thrust washers go, and believe I arrived at a conclusion by running the motor to see how the rotor behaved, and put them in the most logical place.

But there are other members on here who have a lot of motor knowledge.

Incidentally, this is my favorite of the many different motors EMCO fitted to the Unimat. It is quiet, constant speed, and slower than the brush-type ones. But don't let the fan give you false confidence; it can get very hot. I do not consider it suitable for continuous duty.

Martin


-----Original Message-----


Thank you for getting back with me Martin. ?I need to know how to place the thrust washers on the armature. ?I only have 2 of them and not sure if one goes on each end, or due to electric theory and the right hand rule do 2 go on the same end to absorb the torque of the motor starting. ?I haven’t been able to find any literature on this little motor.?

thanks for your help
 

Thanks, I am going to try putting it together with one on each end to start and see where this goes. We will see soon!
 

Look for wear patterns on the washers and match them to the parts. They will have? polished circle sections on the faces and you look at what you have to see what matches up to it. It is like putting a puzzle together. Each section that the washers rub on will leave a different size pattern, match that size to bushing , shaft etc that is the same size.
?Jeff


-----Original Message-----
From: David Rutter via groups.io <mr.rutter@...>
To: Unimat <[email protected]>
Sent: Thu, Apr 16, 2020 4:37 pm
Subject: Re: [Unimat] Unimat DB200 Dutch Motor Diagram #db200

Thanks, I am going to try putting it together with one on each end to start and see where this goes. We will see soon!

 

When in doubt, one at each end. They may serve to stop the rotor rubbing against the moter?ends.

Are they dished or flat or ??

Neil
-----


On Thu, Apr 16, 2020 at 1:07 PM mr.rutter via <mr.rutter=[email protected]> wrote:

Thank you for getting back with me Martin.? I need to know how to place the thrust washers on the armature.? I only have 2 of them and not sure if one goes on each end, or due to electric theory and the right hand rule do 2 go on the same end to absorb the torque of the motor starting.? I haven’t been able to find any literature on this little motor.?


thanks for your help
 

So I got the little motor running. It is a little tight in the bushings though. I know that the rotor should be very loose and able to spin easily by hand. I can spin it but it is not as free as an induction motor should be.

I was going to pull the motor back apart now that I know I can get it running and add a fine lapping compound to the bushings/rotor ends and put it back together and let it run in to see if I am get it free spinning as it should.

Any other suggestions???
 

I would never put any abrasive on the bushings, they are probably oillite bushings made of sintered bronze which has lots of pores to hold oil and you will not be able to clean out? the abrasive. If you think the shaft is too tight on the bushings then there is possibly something in the surface of the shaft which is causing it to bind. I would start with adding drops of light oil to the bushings since they are porous and made to retain oil and let the motor run for a while. If that doesn't work, chuck the armature into a drill and use very fine sandpaper (like 5000 wet dry sandpaper) and lightly clean and polish the shafts.
 

Hi David,
let let preface by saying that my experience is informed by having rebuilt the U90 motor.

I’m only speaking to the motor bushings/bearings.

I’m pretty sure the bushings you’re referring to are oilite bearings, which should not be lapped. Oilite bearings are made of a porous material that stores oil and releases it under heat. That is the simple version. ?Lapping compounds and swarf from the shaft and bearing itself will fill in the bearing surfaces, rendering them less effective or useless.

Did you clean and recharge them, prior to reinstalling them??

This is what worked for me. Your mileage may vary. I soaked the bearings from my U90 in solvent, then put the container under a vacuum. This softens and draws out the old hardened ?lubrication. ?I then placed the bearings in a pot of detergent free oil and drew a vacuum and let it set for an hour after the bearings showed no further signs of taking in oil.

You could also simply clean them with solvent, and soak them in hot oil for...?

it might also be easier to get a replacement set of bearings. These things look like a pretty common size used in sewing machine motors. ? I just picked up a 1954 Pfaff 130 sewing machine that probably would benefit from a correctly done motor rebuild, it seems to run a bit slow.

Cheers,
James
 

As has been suggested, these are probably Porite bearings. Ideally you should use the special oil for these. If you have a business that is local and repairs sewing machines they may have this oil for sale.

They can advise you about the motor and bearings. The bearings are spherical and should automatically align themselves.

Possibly there isn't enough lateral movement in the rotor. I'd expect a little play there, something like 1/64" forward and backwards (along the direction of the shaft).

Neil
-----


On Mon, Apr 20, 2020 at 6:25 AM David Rutter via <mr.rutter=[email protected]> wrote:
So I got the little motor running. It is a little tight in the bushings though. I know that the rotor should be very loose and able to spin easily by hand. I can spin it but it is not as free as an induction motor should be.

I was going to pull the motor back apart now that I know I can get it running and add a fine lapping compound to the bushings/rotor ends and put it back together and let it run in to see if I am get it free spinning as it should.

Any other suggestions???

 

Thanks for information. I will pull the bushings and soak in some hot oil for a while. They looked pretty clean. I took some micrometer readings and and I am amazed at how tight the clearances are from the rotor to the bushing. .001 on the fan end of the rotor and .003 on the other end. Does any one know what these specs are supposed to be.

Thanks for the help. I was just glad that this little motor ran after 50-60 years of sitting. Now it’s time to make it perfect

On Apr 20, 2020, at 11:17 AM, bluerandonee@... wrote:

?I would never put any abrasive on the bushings, they are probably oillite bushings made of sintered bronze which has lots of pores to hold oil and you will not be able to clean out the abrasive. If you think the shaft is too tight on the bushings then there is possibly something in the surface of the shaft which is causing it to bind. I would start with adding drops of light oil to the bushings since they are porous and made to retain oil and let the motor run for a while. If that doesn't work, chuck the armature into a drill and use very fine sandpaper (like 5000 wet dry sandpaper) and lightly clean and polish the shafts.
 

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There is some play laterally along the rotor. ?When I spin it by hand you can feel it dragging in the bushings. I should be able to spin it by hand and it keep going but it isn’t that loose. ?I am going to look for the oil or possibly a new set of bushings for it and see if it will run perfectly. ?This motor has been in pieces for 50 years so I am not surprised it isn’t smooth, but I was amazed i could get it running at all. ?Still a work in progress but it’s coming back to life for sure!

Thanks

Dave


On Apr 20, 2020, at 12:07 PM, Neil Morrison <neilsmorr@...> wrote:

?
As has been suggested, these are probably Porite bearings. Ideally you should use the special oil for these. If you have a business that is local and repairs sewing machines they may have this oil for sale.

They can advise you about the motor and bearings. The bearings are spherical and should automatically align themselves.

Possibly there isn't enough lateral movement in the rotor. I'd expect a little play there, something like 1/64" forward and backwards (along the direction of the shaft).

Neil
-----


On Mon, Apr 20, 2020 at 6:25 AM David Rutter via <mr.rutter=[email protected]> wrote:
So I got the little motor running. It is a little tight in the bushings though. I know that the rotor should be very loose and able to spin easily by hand. I can spin it but it is not as free as an induction motor should be.

I was going to pull the motor back apart now that I know I can get it running and add a fine lapping compound to the bushings/rotor ends and put it back together and let it run in to see if I am get it free spinning as it should.

Any other suggestions???

 

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So I got it running really well and spent some of the day putting it all together. Here is a picture. ?A few more loose ends to tie up and I will be ready to make something. Thanks to everyone who helped with the motor issues

Dave


On Apr 20, 2020, at 12:12 PM, David Rutter via groups.io <mr.rutter@...> wrote:

?There is some play laterally along the rotor. ?When I spin it by hand you can feel it dragging in the bushings. I should be able to spin it by hand and it keep going but it isn’t that loose. ?I am going to look for the oil or possibly a new set of bushings for it and see if it will run perfectly. ?This motor has been in pieces for 50 years so I am not surprised it isn’t smooth, but I was amazed i could get it running at all. ?Still a work in progress but it’s coming back to life for sure!

Thanks

Dave


On Apr 20, 2020, at 12:07 PM, Neil Morrison <neilsmorr@...> wrote:

?
As has been suggested, these are probably Porite bearings. Ideally you should use the special oil for these. If you have a business that is local and repairs sewing machines they may have this oil for sale.

They can advise you about the motor and bearings. The bearings are spherical and should automatically align themselves.

Possibly there isn't enough lateral movement in the rotor. I'd expect a little play there, something like 1/64" forward and backwards (along the direction of the shaft).

Neil
-----


On Mon, Apr 20, 2020 at 6:25 AM David Rutter via <mr.rutter=[email protected]> wrote:
So I got the little motor running. It is a little tight in the bushings though. I know that the rotor should be very loose and able to spin easily by hand. I can spin it but it is not as free as an induction motor should be.

I was going to pull the motor back apart now that I know I can get it running and add a fine lapping compound to the bushings/rotor ends and put it back together and let it run in to see if I am get it free spinning as it should.

Any other suggestions???

 

Dave is it possible to rotate the end plates of the motor?? If so try to rotate one 180 degrees and see if the shaft spins more freely.The binding of the shaft could be just a misalignment of the ends of the motor.
I have had this happen to me before with other motors.
 

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My thoughts are much the same. With the clearance mentioned in one of the other emails a very slight misalignment could cause your symptoms.

You may be able to rotate an end plate in 90 degree steps. There may be four possible rotations of the end plates in relation to each other. Look for scratch marks or scuffs on the outside of the stator housing the end plates that may tell you how it was put together before. Whoever took it apart for you should have marked if for you, but probably didn't. A sharpie line the length of the motor would have done the trick...

I think there may be as many as 16 ways to assemble the motor.

Does it rotate more freely with the screws loosened? torqued differently?

On 4/20/20 7:55 PM, Mike Gidley via groups.io wrote:

Dave is it possible to rotate the end plates of the motor?? If so try to rotate one 180 degrees and see if the shaft spins more freely.The binding of the shaft could be just a misalignment of the ends of the motor.
I have had this happen to me before with other motors.

 

I'm trying to do the opposite. I just got the same motor. It is packed with decades of dust and grease and I'm trying to take it spart to clean.
I removed 2 long screws and 4 screws that hold the capacitor cover. The aluminum end caps sit in the cylindrical body very tight. Do you just pull them out? Anything else I'm missing?
 

Good evening,
?
I'm sorry but I have no experience with the type of motor on your lathe but had a similar problem with the older U90 motor.
It just would not come apart, in fact the previous owner had tried to knock it apart with a hammer using the brush holders as a contact point.
?
Having ascertained that there were no wires holding it, it was just a case of brute force and plenty of sweating and cursing to pull it apart with my hands.
?
Having got it apart it was obvious that it had been put together in a hydraulic press as there was evidence of large scratches inside the case.?
?
Using a Dremmel and small grinding wheel I removed as much excess metal as required to ensure a looser fit.
?
regards,
?
David
 

I finally got the induction motor apart. It wasn't too bad, just not much to grab to without scratching or crushing. It's a solid body and two end caps that protrude very little.
I bolted a wooden plank through motor mounting holes on the front cap (two M5), first drilling an opening in it to allow space for the shaft. Then twisted and pulled by hand. If you have unimat motor mounting bracket, you can use that too to provide more grip.

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