HT MOTOR HAVING HUMMING NOISE
HT MOTOR HAVING HUMMING NOISE
(OP)
we have BOILER FEED PUMP MOTOR OF 300kw HT(3.3kV)directly connected to VCB.Recently after overhauling we are encountering an abnormal humming noise from the motor.Temp of DE & NDE side bearing is very normal as both side bearing has been changed & sleeving done at both side shied bearing housing.No trace of neither abnormal temp rise nor vibration.Checked both side bearings on loaded condition with bearing analyzer & found no issue with it.The noise decreases noticeably under decoupled condition.So,the only problem is to find the origin of the humming noise.
please feel free to ask for more information.
please feel free to ask for more information.






RE: HT MOTOR HAVING HUMMING NOISE
RE: HT MOTOR HAVING HUMMING NOISE
Good luck,
Dave
RE: HT MOTOR HAVING HUMMING NOISE
RE: HT MOTOR HAVING HUMMING NOISE
"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic ù and this we know it is, for certain ù then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". û Nikola Tesla
RE: HT MOTOR HAVING HUMMING NOISE
1) With that size of motor, the rotor could have damaged the laminations of either rotor, stator, or both by removing and reinstalling the rotor.
2) Damaging the rotor laminations when removing the old bearing or by pressing on the new bearings.
3) The bearings are not the correct bearings, for the needed end-thrust of the driven end-thrust.
4) The bearings were not pressed on correctly, to match the driven end-thrust.
5) Is the coupling on the motor shaft set at right spot to match driven end-thrust.
6) Is the coupling flexible or rigid type? Make sure shafts are alight correctly.
7) First check to see if the voltages and amperage are equal on all three phases.
Good luck,
Dave
RE: HT MOTOR HAVING HUMMING NOISE
Just to add to the above, if the motor is medium voltage, check for any circulating current through the bearing. Normally to avoid the shaft circulating current, in the medium voltage motors, one side bearing will be insulated. This is more critical, if the motor is supplied through Variable Speed Drive (VSD or VFD).
RE: HT MOTOR HAVING HUMMING NOISE
can it cause the noise,as there is little weight difference between steel & brass cage?please let me know any of your valuable ideas.
RE: HT MOTOR HAVING HUMMING NOISE
RE: HT MOTOR HAVING HUMMING NOISE
Keith Cress
kcress - http://www.flaminsystems.com
RE: HT MOTOR HAVING HUMMING NOISE