seized induction motor

I've come across a machine that was in a flooded basement, but kept above
the water line. The motor looks to be a generic-like industrial type of
about 1/3hp. It's seized, probably from the humidity but there's no
visible corrosion from peeking inside the bell on one end.
It there some less-hard way to try to separate the stator from the rotor,
aside from taking the bells off, banging on it with a hammer until
something bends or the hammer slips and then tossing out to get a new
motor?
Again, the appears great- there's no visible corrosion, but something has
to be going on in the gap in order to seize it.
Reply to
Cydrome Leader
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Soak it in Kroil then take it apart.
Reply to
Tom Gardner
Be carefull taking it apart. There may be a centrifugal switch inside the end case on the shaft end that is easily damaged if you don't know it's there. I think I'd just buy a new motor and be done with it. Bearings are probable shot and may cost $10 each to buy and a couple of hours work replac> > I've come across a machine that was in a flooded basement, but kept above
Reply to
Gerry
Yup - just move straight to tossing out the motor (or seeing if the scrapyard is interested, and letting them take it apart), while you move on and don't wast time on a cheap, easily replaced, part. You probably won't do this, but it is the easier way.
Reply to
Ecnerwal
Might be the bushing or bearings are locked. Martin
Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member.
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Cydrome Leader wrote:
Reply to
Martin H. Eastburn
A new 1/2 HP motor is $30 to $100, depending on whether it's a generic motor that they sell by the thousands or an oddball that you have to special order in and takes a few days.
It's simply not worth the effort fixing the old one, especially at what most people's time is worth if someone's paying you. You'll diagnose the problem, ID and find the repair parts, and fix the bearings - and a month later the start switch will break. Then you have to start repairing all over again (good luck locating a fractional HP motor start switch easily and quickly) or toss it with that other repair effort wasted.
When you get up to 5 HP, then fixing starts making sense for simple stuff. 10 HP, most likely - unless something's seriously wrong. 25 HP and up, new motors stop being cheap, and you definitely send the failed motor out to get rebuilt.
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Reply to
Bruce L. Bergman
while all the posts saying just discard it are valid, it is quite possible that this is a motor with bushings, or where grease has hardened, and if you have more time than money, it's not hard to fix - use heat and solvents to loosen the bearings, regrease and reassemble - clean up any switch contacts - I have motors I repaired 30 years ago that are still working fine. Yes, if you are getting paid $135 an hour, then just change it, but if you are working for $0, then fix
Reply to
William Noble
>Might be the bushing or bearings are locked. >Martin > >Martin H. Eastburn >@ home at Lions' Lair with our computer lionslair at consolidated dot net >TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. >NRA Second Amendment Task Force Charter Founder >IHMSA and NRA Metallic Silhouette maker & member. >
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> > >Cydrome Leader wrote: >> I've come across a machine that was in a flooded basement, but kept above >> the water line. The motor looks to be a generic-like industrial type of >> about 1/3hp. It's seized, probably from the humidity but there's no >> visible corrosion from peeking inside the bell on one end. >> >> It there some less-hard way to try to separate the stator from the rotor, >> aside from taking the bells off, banging on it with a hammer until >> something bends or the hammer slips and then tossing out to get a new >> motor? >> >> Again, the appears great- there's no visible corrosion, but something has >> to be going on in the gap in order to seize it. >> >> > >
Reply to
clare at snyder.on.ca
If you don't want to take the end bells off, I would put on a large pulley if you have one that fits and see if there is any movement at all when you try to rotate the shaft. Like you I doubt if the problem is in the bearings. They are greased and not likely to have rusted solid. The problem is most likely to be a slight amount of rust between the stator and rotor at the place where the clearance is the least.
Unlike others, I would remove the end bells and see if the rotor won't come out of the stator. Putting a little light oil between the stator and rotor would likely free it up. To me definately worth spending half an hour or 45 minutes just to see what the cause actually is. Time better spent than watching most television programs or engaging in the off topic threads in RCM.
Dan
Reply to
dcaster
> > >>Might be the bushing or bearings are locked. >>Martin >> >>Martin H. Eastburn >>@ home at Lions' Lair with our computer lionslair at consolidated dot net >>TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. >>NRA Second Amendment Task Force Charter Founder >>IHMSA and NRA Metallic Silhouette maker & member. >>
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>> >> >>Cydrome Leader wrote: >>> I've come across a machine that was in a flooded basement, but kept above >>> the water line. The motor looks to be a generic-like industrial type of >>> about 1/3hp. It's seized, probably from the humidity but there's no >>> visible corrosion from peeking inside the bell on one end. >>> >>> It there some less-hard way to try to separate the stator from the rotor, >>> aside from taking the bells off, banging on it with a hammer until >>> something bends or the hammer slips and then tossing out to get a new >>> motor? >>> >>> Again, the appears great- there's no visible corrosion, but something has >>> to be going on in the gap in order to seize it. >>> >>> >> >>
Reply to
Cydrome Leader
I sympathize with the desire to restore and repair things, but is it really worth even your hobby time to try to restore a generic 1/3 HP motor? They are so cheap to replace that, unless it is a special purpose motor, I'd consider junking it.
If you really want the challenge of fixing it instead of replacing it (and I have taken that path many times to the amazement of and ridicule by my friends), you will probably have to replace the bearings anyway, so why not pull the end bells to start with? If you can't see any corrosion looking into the rotor/stator gap, the bearings must be seized. You are not going to be able to "restore" ball bearings short of replacement.
awright
> clare wrote: >> >> >>>Might be the bushing or bearings are locked. >>>Martin >>> >>>Martin H. Eastburn >>>@ home at Lions' Lair with our computer lionslair at consolidated dot net >>>TSRA, Life; NRA LOH & Endowment Member, Golden Eagle, Patriot"s Medal. >>>NRA Second Amendment Task Force Charter Founder >>>IHMSA and NRA Metallic Silhouette maker & member. >>>
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>>> >>> >>>Cydrome Leader wrote: >>>> I've come across a machine that was in a flooded basement, but kept >>>> above >>>> the water line. The motor looks to be a generic-like industrial type of >>>> about 1/3hp. It's seized, probably from the humidity but there's no >>>> visible corrosion from peeking inside the bell on one end. >>>> >>>> It there some less-hard way to try to separate the stator from the >>>> rotor, >>>> aside from taking the bells off, banging on it with a hammer until >>>> something bends or the hammer slips and then tossing out to get a new >>>> motor? >>>> >>>> Again, the appears great- there's no visible corrosion, but something >>>> has >>>> to be going on in the gap in order to seize it. >>>> >>>> >>> >>>
Reply to
Anne Irving
Actually yes it is worth my time. Anthing I can fix the first time I can probably fix again. I suspect the bearings are fine, and there is corrosion between the stator and rotor.
There is no intention to fix bearings here, just to unfreeze the rotor which is probably the issue. I'm sure I could squirt all sorts of chemicals in there, but they're probably not good for the windings.
People list 500 ways to remove broken threaded inserts here, I was hoping to hears stories on tricks for motors.
Reply to
Cydrome Leader
I just hadda replace the bearings in a 1/2 hp motor. Finished the job about an hour ago. Some motors will have one bearing retained by a circlip or a plate with screws, etc. When you take off the end bells keep this in mind. However, most induction motors will have the bearings pressed onto the rotor and the bearings just float in the end bells. One bell will have a wave spring or similar to keep the rotor in place. This is because of the centrifugal switch in the motor. Usually the spring will be in the end bell opposite the end of the motor that has the switch. Most motors will allow the end bell at the switch end to be withdrawn while leaving the rotor in place. I did work on one motor that had a centrifugal switch assembly that required the rotor to be withdrawn with the end bell. But only once. It was a long time ago on an old motor and I bet that it was done this way to avoid patent infringement. Better motors will have a steel ring pressed into the aluminum end bells. The bearing slip fits into this ring. This allows the bearing to float back and forth without wearing out the bearing bore in the end bell. Every motor I have seen that has a fan pressed onto the rotor shaft will not have a bearing retainer in the end bell at that end. Match mark the end bells before removing. I remember putting an old buffer motor back together that had no centrifugal switch and identical end bells. l had not match marked anything but had put a nice new coat of grey paint on everything. When assembled the first time the rotor was rubbing the stator. It made a terrible noise when first powered up. It took me a few tries to get the end bells right. Now I match mark with a punch or with a parting disc in the Dremel (my favorite). The bearings for the motor I did today were about $3.50 each. These are number 6203 ZZ double shielded bearings. ERS
Reply to
Eric R Snow
It turns out the fix was easier than expected.
Tear into the shaft with Knipex pliers and torque it.
Whatever was stuck broke free. All sorts crap blew out the motor. The bearings were ball, and sound fine. The shaft turned fine, with just the rough feel from the starter contacts. The motor runs fine now.
It would have been more interesting to tear it apart, but maybe that's for the next time.
Reply to
Cydrome Leader
You might wanna try the ceramic balls bearings, they call them hybrid ceramics, the inner and outer rings are steel, but balls are ceramic, I found them in VXB bearing website, the website is called
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and the item name is Kit7547
1/2 hp motor. Finished the job
Reply to
Bearings.Expert

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