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In our work place we rewinded 2.6KW/7.5KW motor succesfully and tested with tachometer RPM/load current everything same (compare with new motors).
we completed 3Nos of 7.5KW and 5Nos of 2.6KW.
Now we are getting continuous fail. Is there any standard formula related 3 phase Motor rewinding or coil size specification details.
Please reply electwar @ gmail.com
Hari, it would be fruitless to provide an answer until you furnish some some data:
1) What is failure-rate? Mean-Time-To-Failure?
2) What is the mode-of-failure, i.e., phase-to-earth; phase-to-phase; 3-phase overcurrent; within slot or in terminal box; turn-to-turn; single-phase blowout; pigtails; bearing failure; etc?
3) Are rewind materials, i.e., copper-size, insulation class, the same as original, or upgraded?
4) What about application: one-speed; two-speed; VFD?
5) How about starting method: DOL; conventional reduced-voltage methods; soft-start?
6) You mentioned amperes and speed being the same, but how about: slip; locked-rotor test parameters; uncoupled-test results?
6) Same or different rewinder(s)?
7) What method do you use to remove wire from stator?
8) Are cooling fans (if used) reinstalled?
The above should give you some ideas!
Regards, Phil Corso (firstname.lastname@example.org)