Need help with a motor problem

[Rata221]

Need help with motor problem. I am not that knowledgeable about electrical or motors.
I purchased a used 1/3 HP 1725 (sleeve bearings) motor to use on a drill press restoration. The motor/drill runs fine at the three lower speeds even- under the load of drilling steel. The motor tachs at 1760 RPM. If I move the belt to the largest pulley on the motor – under no load- the motor will only rev up to 1100 RPM and you hear the centrifugal switch open.
If I remove the belt from the drill spindle pulley, the motor revs up to the 1760. I attempted to put a load on the motor, by pressing wood against the pulley, and it doesn’t bog down.
The start capacitor tested OK with ohm meter – but I replaced it anyway since it looked like it was starting to leak. I doubled checked the wiring per the diagram on the motor. I had put new bearings in the drill spindle on rebuild - it turns very smoothly – so I don’t believe that is the culprit.
Only thing that I can think of is that the centrifugal switch is opening to soon (the motor staring slower in the higher gear or Maybe being in the vertical position? Needs stronger springs? I know sleeve bearing are not the best to run vertically.
Does anyone have any ideas about what might cause this? Or what I might try to fix it?
Thanks. Jim

 

[dogdog]

Not enough power ?

 

[ez-duzit]

Replace the motor with the same spec motor as the original.

 

[walta]

Most sleeve bearings are made for the shaft to be horizontal. I think you will need to find a ball bearing motor.

Walta

 

[Rata221]

Not enough power ?

Replace the motor with the same spec motor as the original.

Thanks for the replies.
The drill is small. The manual calls for a 1/4 to 1/3HP motor. The original was a 1/3 HP. If working correctly a 1/3 HP should easily spin up the spindle with no load but wasnt sure how to troubleshoot it.

Most sleeve bearings are made for the shaft to be horizontal. I think you will need to find a ball bearing motor.
Walta

I agree 100% that the sleeve bearings are not the best way to go.

Thanks again - Jim

 

[TractorJeff]

There is frictional forces to overcome in that high speed mode which are exacerbated by the fact that it is at the top of the shaft. Sleeve Bearings in the Motor and probably Sleeve Bearings in that Vintage Drill Press plus a Stiff Belt.

 

[Rata221]

TractorJeff
I had not considered any of the things that you mentioned
I had not really thought about the added resistance leveraged by the pulley being at the top. And yes the belt is stiff. I will get a serrated belt and try that and see if that helps.
Thank you - Jim

 

[TractorJeff]

Is it a Dumore brand?
Those old tools were works of Art!

 

[Rata221]

Is it a Dumore brand?
Those old tools were works of Art!

It is a Rockwell 11-100. I enjoy restoring and using old machinery. The old machines and castings do look like art, to me.
Though the current belt is not real tight -I ordered a a longer cogged belt that that will allow me a little looser, more flexible fit. I will let you know if that resolves the problem
Thanks
Jim

 

[ard]

Is there a run/start capacitor on that motor?

 

[nsula_country]

TractorJeff
I had not considered any of the things that you mentioned
I had not really thought about the added resistance leveraged by the pulley being at the top. And yes the belt is stiff. I will get a serrated belt and try that and see if that helps.
Thank you - Jim

I think we have a winner. Friction and leverage.

Good luck

CT

 

[Rata221]

Well…..The longer cogged belt came in today. The new belt is very flexible. I put it on the drill press but no joy- the problem still existed. Would not rev up past the 1100 RPM in the high gear.

Each of the cone pulleys consist of a 5”, 4” 3” and 2” pulley. The 5” motor pulley is intended to drive the 2” spindle pulley and this is the speed that doesn’t work. I shifted the motor up and down and ran the 5” motor pulley to the 3” spindle (instead of the 2”) and it ran fine. Also ran the 4” motor pulley with the 2” spindle and it ran fine.

I flipped the cone pulley on the motor so the large 5” pulley was on the bottom of the shaft, closer to the motor. The pulley on the drill spindle could not be flipped – so I raised the motor and clamped it in place so the belt ran true in the pulleys. I tried it about 10 times and a few times it ran at the 1725, the other times it stayed at 1100 RPM. So having the pulley not extended out on the shaft helped some.

The bearings in the spindle are new Koyo bearings they sound fine in all the speeds – I ran them in at all three lower speeds and they produced no heat in the spindle that I could tell.

As suggested by TractorJeff I believe all the frictional and levered forces in the pulley arrangement may just be too much for this particular GE motor. It is a small Delta Rockwell drill press. The manual calls for a ¼ HP but recommends a 1/3 HP for heavy work.

My objective in restoring the drill press was to do it right and make it last another 50 yrs for whoever has it. I gave up on that motor, and hesitantly repaired the starting switch in the old motor with some JB Weld and a piece of brass. It may or may not last.

I put the repaired? old motor back on the drill press and it ran full speed in high gear easily. It is also a 1/3 HP sleeved bearing motor – with the heavy casted bells on the end. Just must be stronger. I let it run for about 20 minutes and the spindle bearings sounded fine and did not get hot.

The top speed was 4300 RPM. I will probably never use the high gear anyway and maybe never use the drill press. I have a large drill press I use.
The project - and enjoyment- for me was the restoration of an old, beautiful, piece of machinery that I can give to someone who will appreciate it. My girlfriend’s son is wanting to get into woodworking. AND I just hate to not be able to fix something or not understand the problem.

Thank you guys for the ideas and input.
Jim

 

[ard]

second time: is there a capacitor in the 'new' motor?

 

[Rata221]

second time: is there a capacitor in the 'new' motor?

Yep, stated that in the original post.

The capacitor tested good, but I replaced it anyway since it appeared to be starting to leak. The old capacitor was GE same as the motor - so hopefully it is the original and the correct capacitance.

 

[ard]

Yep, stated that in the original post.

The capacitor tested good, but I replaced it anyway since it appeared to be starting to leak. The old capacitor was GE same as the motor - so hopefully it is the original and the correct capacitance.

If it were a cap issue, it would be the 'run' capacitor. One gets it spinning, the other keeps it at full load and rpm. At least thats my experience with larger motors

GL!

 

[The Cobbler]

a 1/3 HP fan duty motor(furnace) may have different "geometry" than a drill press motor too as far as torque, starting etc .