Scope of Work for overhaul E-motor

[WvPetegem]

Hello everyone.

I was wondering if somebody could advise me what the 'standard' scope of work is for an overhaul of an 3-phase 400V E-motor (like type 225M).
Renewal of bearings and cleaning of the coils are obvious; but should works like 'rewinding of stator/rotor coils' also be advisable?
And if rewinding is advisable, should it be the stator or rotor coils, or both?


Furthermore; what is the procedure (work sequence) for baking/drying the coils (in an oven)?

Any details and information is more than welcome! Thanks in advance!

 

[ozmosis]

This might be a start:

http://www.easa.com/sites/default/files/AR100-2010_1010-2.pdf

 

[electricpete]

EASA AR-100 is good. I'd go with that one.

Here is another one, not quite as good.

http://www1.eere.energy.gov/manufacturing/tech_deployment/pdfs/repair_specs_motors.pdf

but should works like 'rewinding of stator/rotor coils' also be advisable?

That's a judgement call, depends in part on age and condition of original coils.
It may sound a little backwards, but you can ask the repair shop to inspect the motor and make a recommendation. Most will give you good honest advice.

And if rewinding is advisable, should it be the stator or rotor coils, or both?

Most motors are squirrel cage induction motors - no rotor rewind to worry about.
If you have wound rotor, evaluate rewind based on condition.

=====================================
(2B)+(2B)' ?

 

[petronila]

Hello WvPetegem

Adding more information, following could help:

1. Take complete name plate data and record
2. Make a complete visual insopection, looking for missing or broken parts
3. Take an IR, IP and Surge Test: You will know if neccesary rewind or not
4. Mark the shields: one point D.E side two points N.D.E side, this is important when you assembly the motor.
5. Dissmount the motor.
6. Verify the stator, if is burned(you will know in the early test) note the cause, if it is not burned look for contamination, rust, grease, etc
7. Take note of bearing type and references
8. Dismount bearings and verify fits in shaft and shield bearing housings
9. verify squirrel cage (use a growler or other equipment like core tester)
10. Perform the rewinding: Take complete data, perform a core tests before burning, burn off the windings, clean, install new insulation(same insulation class or higger), new copper, connect and Test: IR, PI,Surge and hipot. or perform the maintenance: Clean the windings with dielectric solvents, bake and IR, IP re test if all . End Step for both: Apply varnish or VPI the windings and bake.
12. Verify the shaft is not bent.
13. Perform mechanical works if is necesary (machinning, sleeving, etc).
14. Find all spare parts you need and start the assembly, install the bearings,make lubrication and replace defective parts if is necesaary(fan, fan cover, terminal block, etc)
15. Once you finish, verify turning by hand the shaft moves freely and make a final IR test.
16. Power the motor and test with rated voltage and connection.
17. verify no load current and abnormal sounds.
18. If you can test the motor with load that will be better.
19. End painting.

Regards

Carlos

 

[dArsonval]

Surprised the Electrical Apparatus Service Association, (EASA)... is allowing this thread to continue.

People pay membership dues for this information. The posted link in this thread appears to be a free URL though... so go figure.

Nothing replaces actual "experience" though.

John

Always enjoying this place ; )

 

[ozmosis]

John
I do respect copyright. The link is freely available on their site, so I see no infringement of data.

 

[oldfieldguy]

The information is hardly an industrial secret. Reputable motor shops, whether EASA members or not, as well as industry professionals know this information.


old field guy

 

[WvPetegem]

Thanks guys, for all the useful info!

It's clear to me. In general rewinding for a non-defective E-motor is not advisable (since costs will be increased).