We continue to experience higher than acceptable overall vibration levels in large, say 900 to 1250 hp two pole, Babbitt bearing electric motors. The predominant peak vibration energy is usually 3X in either the vertical or axial plane.
Current Example: outboard vertical reading 1.3 ips...
I can understand the desire for this test on a new winding designed to pass such a test, but have never been able to get a winding to pass once it has been in service, even after a second VPI and cure.
Is it practical to expect an original immersion winding to pass the IEEE 429 after being in...
Customer refuses validity of acceleration envelope readings to detect rolling element defect frequencies in newly installed bearings.
Specifies no more than 3 peaks in a single spectrum in alignment with a bearing element frequency with an amplitude greater than .0049 i/s.
does this seem...
GE specifies a hot advance of their locomotive traction motor pinions of .085" to .100".
GM and MKO specifies only .055" hot advance and the taper is basically identical in angle, length and diameter. We are actually going to about .070".
Of about 80 of these motors done, where pinion...
100 hp Reliance IEEE 841 design 1200 rpm (6 pole) motor.
Running on PWM VFD. Is there a standard for frequencies over 60 hz. or a maximum speed rating for motors.
I know on larger motors peripheral speeds should not exceed 10000 ft/min but what about a guestimated 13" rotor core diameter?
Can anyone explain the basic theory behind pole amplitude modulation in an electric motor. I have a 6500 hp with 9 leads connected 2 par star on high speed (894) and series delta on low speed (710). Motor has 120 slots/coils. I can see no change in poles when reconnecting from 2 wye to 1 delta...
Customer has 3 each 75 hp Reliance standard duty motors, 4 pole, 460 vac, tefc that run from ROM stacks of coal for train loading.
They need to start blending these stacks and want to slow down the feed on the belts based upon sulphur content etc.
The worst scenario the engineers can see is...
A customer reports finding first high freq vibration in the 130 to 180kcpm range, with one of the high peaks at 2BSF.
He suspected fluting and then discovered it upon disassembly. I am somewhat familiar with shaft currents in AC Induction motors, but haven't encountered it in DC.
This is a...
