Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

Thanks in advance to everyone.

Ignoramus8644 wrote:
On 30 Aug 2005 12:37:58 -0700, Rooster wrote:
Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

I have a webpage where I show how I did it.

You should use a bearing puller and be careful removing rear end bell
(for single phase motors).

http://igor.chudov.com/projects/Repl...lectric-Motor/

i

Don't know if it will not come out of the housing, but as far as
removing from the armature you could and prob should press them on and
off to prevent damage to the bearings from stricking them.

There's a good article on replacing motor bearings in the latest ed. of Home
Shop Machinist. It tells about making a sleeve for a replacement bearing
that was too small.

Bob Swinney
"DJ" wrote in message
oups.com...
Don't know if it will not come out of the housing, but as far as
removing from the armature you could and prob should press them on and
off to prevent damage to the bearings from stricking them.

"Rooster" wrote in message
oups.com...
Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

Thanks in advance to everyone.


I'm not an expert, but I rent my store front out to guy who does motor
rewinding. I've seen him many times heat the bearing to remove and replace
it on the armature. You also want to check how the bearing seats in the
housing. I've seen some motors that the seat was out of round and loose, and
the bearing was good.

Randy H

"Rooster" wrote in message
oups.com...
Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

On the submarine (at sea) we did not have access to fancy hydraulic
presses, so we carefully cut off the old bearing with a die grinder and heated
up the new bearing in the galley oven. I understand that they later got
induction heaters, but I'll bet they still use the die grinder.

Vaughn

Die grinder? I can hear the sonar watch levitating and fighting the
urge to scream "high speed screws in the water"

I don't understand what all the fuss is about on this thread. I've been
rebuilding small electric motors all my life and have never had any instructions
whatever. Take them apart, replace the bearings, clean them out a little, make
sure all's a'tanto, put them back together the same way they were.

On really little motors I've sometimes had trouble

1) getting the centrifugal switch mechanism off correctly
2) getting the bells centered since they're built too lightly

To deal with the centrifugal switch, I try to gently remove the bell on the far
end from the shaft first, and see what I can see. Lots of times the armature
will slide out.

I have never had big trouble removing bearings from any motor up to 7.5hp and
I've never worked on anything bigger.

To deal with the bell centering issue (on reassembly) I mark the bells before
disassembly so I can replace them exactly as they were. Then I assemble the
motor lightly, and run it on the bench and tap the bells with a soft hammer
until they run as quietly as possible, then tighten them. I've gotten a couple
of small cheap motors to quiet down quite a bit this way.

Motor stators like being blown out with compressed air.

The only motors that I hate are the ones that when you run them they're noisy,
then when you cut the power for an instant, while they're still virtually at
full speed, they run silently, then when you restore the power, the noise
returns. Those I've never been able to fix, so I have always replaced them and
let the noisy ones go.

GWE

Jeez, silly me, I never even thought of buying one, I just took mine apart and
made some longer straps for it ..

GWE

Ignoramus27122 wrote:
I am curious where can I buy a very deep bearing puller. (for taking
bearings off shafts that protrude about 6-7 inches beyond the bearing.

i

On Wed, 31 Aug 2005 09:26:03 -0700, Grant Erwin wrote:

I don't understand what all the fuss is about on this thread. I've been
rebuilding small electric motors all my life and have never had any instructions
whatever. Take them apart, replace the bearings, clean them out a little, make
sure all's a'tanto, put them back together the same way they were.

On really little motors I've sometimes had trouble

1) getting the centrifugal switch mechanism off correctly
2) getting the bells centered since they're built too lightly

To deal with the centrifugal switch, I try to gently remove the bell on the far
end from the shaft first, and see what I can see. Lots of times the armature
will slide out.

I have never had big trouble removing bearings from any motor up to 7.5hp and
I've never worked on anything bigger.

To deal with the bell centering issue (on reassembly) I mark the bells before
disassembly so I can replace them exactly as they were. Then I assemble the
motor lightly, and run it on the bench and tap the bells with a soft hammer
until they run as quietly as possible, then tighten them. I've gotten a couple
of small cheap motors to quiet down quite a bit this way.

Motor stators like being blown out with compressed air.

The only motors that I hate are the ones that when you run them they're noisy,
then when you cut the power for an instant, while they're still virtually at
full speed, they run silently, then when you restore the power, the noise
returns. Those I've never been able to fix, so I have always replaced them and
let the noisy ones go.

GWE

On 30 Aug 2005 12:37:58 -0700, "Rooster" wrote:

Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

Thanks in advance to everyone.

Go to http://www.ntnamerica.com/ and click on Technical Support. Then
click on "On-line Catalogue / Interchange ", then "Engineering
Information" at the top. Finally, under Engineering Documents click on
"Proper Practice for the Cleaning, Mounting, and Removal
of Bearings ". Should find a lot of good info there. Please
note that when it discusses oil immersion heating to only do that with
open bearings. You can flush the grease out of sealed or shielded
bearings with that method. Good luck - take care.

Tom..........

Good link Tom. There's an interesting item in their FAQ

What does the term "electric motor quality" mean?
The term "electric motor quality" is freely used in describing
bearings that meet a perceived "higher" level of quality than the
standard ABEC1 bearing. Contact NTN marketing for an Electric Motor
Quality brochure.

I'd not heard the term before.

Roger


Tom wrote:
On 30 Aug 2005 12:37:58 -0700, "Rooster" wrote:


Hi,

Is there any online info 'splainin how to replace ball bearings in
electric motors? The last professional craftsman who did it for me put
the armature in a vise and whacked the bearing off with a big hammer,
ruined the motor, etc.

Thanks in advance to everyone.


Go to http://www.ntnamerica.com/ and click on Technical Support. Then
click on "On-line Catalogue / Interchange ", then "Engineering
Information" at the top. Finally, under Engineering Documents click on
"Proper Practice for the Cleaning, Mounting, and Removal
of Bearings ". Should find a lot of good info there. Please
note that when it discusses oil immersion heating to only do that with
open bearings. You can flush the grease out of sealed or shielded
bearings with that method. Good luck - take care.

Tom..........

On Thu, 01 Sep 2005 12:24:19 GMT, rlincolnh
wrote:

Good link Tom. There's an interesting item in their FAQ

What does the term "electric motor quality" mean?
The term "electric motor quality" is freely used in describing
bearings that meet a perceived "higher" level of quality than the
standard ABEC1 bearing. Contact NTN marketing for an Electric Motor
Quality brochure.

I'd not heard the term before.
It's a subjective term that originated years ago when electric motor
manufacturers demanded quieter, longer lasting bearings. In order to
achieve that, bearing manufacturers had to concentrate on surface
finish, ball grade, ring roundness, cage design and quality and
manufacturing repeatability. There are no industry standards for this
term so "electric motor quality" can vary from one manufacturer to the
other. In more general terms, it means that a bearings should be quiet
running, high quality and have C/3 internal clearance. SKF designates
its electric motor bearings with an EM suffix. This insures that it
has a better surface finish, C/3 clearance etc. NTN only makes one
grade of bearing which is considered to be EM quality. Virtually all
of their bearings will meet ABEC 3 standards or higher even though
they are sold as ABEC 1. In order to insure the highest quality I
would recommend sticking with the major manufacturers such as NTN,
NSK, FAG, SKF, Fafnir, MRC - all of which make good quality bearings
although the first 4 were rated in that order by a DuPont quality
study.