# Motor hums, doesn't know 'Quietly"



## T Bredehoft (Jan 9, 2018)

My Atlas/Clausing MK2 lathe came to me with a Westinghouse motor SER DH76, S#317P 025 Type FHT, 115 V 6.1 A, FR SSB562. 1/3 HP
(I don't know if any or all of that is meaningful. )  When I got the lathe, either 3 or 4  years ago, the lathe itself showed no wear on the ways, I have to assume the motor may have been original. Anyway, it's taken to growling, enough that it transmits a nasty chatter to the tool as it cuts. With the belt unhooked, it still growls badly. 
Is it time to replace the motor? is there anything I can do to reduce the growl? Is there a equal sized DC motor I can substitute? if so where do I look for it.?


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## Billh51 (Jan 9, 2018)

I think I would try and determine the source of the problem and then decide if the motor needs replacing. It could be several things contributing to the noise and chatter. I would first check to see if the motor mounting bolts are loose. If not, then back them off and remove the drive belt and check it’s condition. Check for loose set screws on the pulleys. Turn the shaft over by hand and see if there is any resistance to rotation, possibly bad bearings.
 I guess where I’m heading is to see if is possible to determine whether it is a mechanical problem or if not, electrical. If you can get headed in the right direction, it shouldn’t be a hard problem to solve. Just a matter of eliminating one source of the problem at a time, then move on to the next.
 Others here will chime in and help you get up and running, good luck.
Bill


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## markba633csi (Jan 9, 2018)

So is it a hum like 60 cycle or is it more like a nasty garbage disposal type of noise?  If the latter then probably a bad bearing
Mark


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## T Bredehoft (Jan 9, 2018)

Growl is there with the pulley removed.  Mounting screws are tight, there's a rubber damper (1/16) under the mounts.  It may be a 60 cycle hum, but its kinda raspy. I'll put a stethoscope on each end....

The bearing away frm the pulley has a real rasp to it.


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## T Bredehoft (Jan 9, 2018)

I'd guess the 'rest' the motor had between mfgr (ca 1970 or so and 2015 let the bearing go dry.  Is there a currently produced motor that would take it's place, or are bearings easily replaceable?


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## Dave Paine (Jan 9, 2018)

Lots of internet videos and articles on replacing bearings in motors.    You should be able to replace the bearings.   Need to get them out to find the code/size.

An example video.   The ends are pulled apart around the 7min mark.  In this video the bearing came off with the shaft.  Sometimes they stay with the end.

Motor rebuild video

This may be closer design to your motor.

Craftsman motor rebuild


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## markba633csi (Jan 9, 2018)

Could it be a sleeve bearing motor? I could see that going dry


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## CluelessNewB (Jan 9, 2018)

I would suspect bearings.   Does you motor have a sticker that says something like this 





If the bearings are crunchy you should replace them, sealed bearings are probably a better choice than the originals which are most likely shielded on one side and open on the other.


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## FOMOGO (Jan 9, 2018)

x2 on bearing replacement. Generally pretty easy job. Mike


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## T Bredehoft (Jan 9, 2018)

CluelessNewB said:


> . Does you motor have a sticker that says something like this



No but it does mention intermittent service, so many drops over 5 years..... I'll look into bearings, but I need it soon, may have to run it with wobbly bearings.


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## talvare (Jan 9, 2018)

T Bredehoft said:


> I'll look into bearings, but I need it soon, may have to run it with wobbly bearings.


Tom,

If the problem is a bad bearing (very likely) it's a pretty simple job to replace the bearings. But, if you continue to run it as-is, you run the risk of a bearing spinning on the rotor shaft or spinning in one of the end bells. If that happens with a small motor like you have, it will likely not be economical to repair at that point. So, I would suggest you fix it as soon as possible.

Ted


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## Ulma Doctor (Jan 9, 2018)

T Bredehoft said:


> No but it does mention intermittent service, so many drops over 5 years..... I'll look into bearings, but I need it soon, may have to run it with wobbly bearings.


Hey Tom,
if you get some sizes off the bearings, or some measurements- 
i have lots of bearings- i could send you a couple bearings, free of charge


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## T Bredehoft (Jan 9, 2018)

When I spin it by hand it is smooth as silk. no rumble at all. Flip the switch its' growling.  Could there be something electrical happening? 

I've got an old motor I'm going to switch in, I need to polish some stuff, the grumble/roar is distracting.


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## middle.road (Jan 9, 2018)

Wouldn't a 1/2 or 3/4 HP motor be a better for this hunk of iron?


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## Ulma Doctor (Jan 10, 2018)

T Bredehoft said:


> When I spin it by hand it is smooth as silk. no rumble at all. Flip the switch its' growling.  Could there be something electrical happening?
> I've got an old motor I'm going to switch in, I need to polish some stuff, the grumble/roar is distracting.


there could be a fault in the field windings or a short circuit between the rotor and the windings, at a guess


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## T Bredehoft (Jan 10, 2018)

middle.road said:


> Wouldn't a 1/2 or 3/4 HP motor be a better for this hunk of iron?



The .33 hp motor has been adequate for the turning I'm doing. mostly aluminum, the steel is generally under 3/8" diameter,  I'm looking now for a replacement. I dread the idea of replacing the bearings and finding out that they were OK, that it was something else.


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## talvare (Jan 10, 2018)

T Bredehoft said:


> When I spin it by hand it is smooth as silk. no rumble at all. Flip the switch its' growling.  Could there be something electrical happening?



I have seen a couple of motors that had stator bars coming loose and causing this type of noise. It's not very common and if that is the case with your motor, it's not worth repairing.

Ted


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## T Bredehoft (Jan 10, 2018)

I've jury-rigged my 1/8 hp motor to turn the lathe for a polishing job I've gotten into. Ordered an new motor, should be here next week.

Thanks for all your help and suggestions.


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## T Bredehoft (Jan 11, 2018)

I ordered a new Dayton (made in China)1/3 horse motor yesterday, it was delivered this morning, UPS. It's mounted behind the lathe, running like a champ. I only got two units polished with the old timey motor, (I figure it's pre-WWII)  it worked fine, but not enough hours in the day.


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## markba633csi (Jan 11, 2018)

That's fast service!


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