Nidec LSA 52.3 - Mechanical Defects

Electric Power Generation
Installation and maintenance
5382 en - 2022.11 / h
LSA 52.3 / LSA 53.2 / LSA 54.2
Industrial Range Alternators
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30
5.15 MECHANICAL DEFECTS
Fault Action
Bearing
Excessive overheating of one or
both bearings
(bearing temperature 80°C above
the ambient temperature)
- If the bearing has turned blue or if the grease has turned
black, change the bearing.
- Bearing not fully locked (abnormal play in the bearing cage)
- End shields incorrectly aligned
Abnormal
temperature
Excessive overheating of
alternator frame (more than
40° C above the ambient
temperature)
- Air flow (inlet-outlet) partially clogged or hot air is being
recycled from the alternator or engine
- Alternator operating at too high a voltage (>105% of Un on
load)
- Alternator overloaded
Vibrations
Too much vibration
- Misalignment (coupling)
- Defective mounting or play in coupling
- Rotor balancing fault (Engine - Alternator)
Excessive vibration and humming
noise coming from the machine
- Phase imbalance
- Stator short-circuit
Abnormal
noise
Alternator damaged by a
significant impact, followed by
humming and vibration
- System short-circuit
- Misparalleling
Possible consequences
- Broken or damaged coupling
- Broken or bent shaft end
- Shifting and short-circuit of main field
- Fan fractured or coming loose on shaft
- Irreparable damage to rotating diodes/AVR, surge suppressor