Mechanical Defects; Electrical Faults - Leroy Somer LSA 49.1 4P Manuel D'utilisation Et D'entretien

LEROY-SOMER

4.4 - Mechanical defects

Fault
Excessive overheating of one or both
Bearing bearings (temperature > 80°C on the
bearing retainers with or without abnormal
noise)
Abnormal Excessive overheating of alternator housing
temperature (more than 40° C above the ambient
temperature)
Excessive vibration
Vibration
Excessive vibration and humming noise
coming from the machine
Alternator damaged by a significant impact,
Abnormal noise followed by humming and vibration

4.5 - Electrical faults

Fault Action
No voltage at no Connect a new battery of 4
load on start-up to 12 volts to terminals E-
and E+, respecting the
polarity, for 2 to 3 seconds
Voltage too low Check the drive speed
Voltage too high Adjust AVR voltage
potentiometer
Voltage Adjust AVR stability
oscillations potentiometer
Voltage correct Run at no load and check
at no load and the voltage between E+
too low when on and E- on the AVR
load (*)
(*) Caution : For single-phase operation, check that the sensing wires coming from the AVR are correctly connected to the operating terminals
Voltage Check the AVR, the surge
disappears suppressor, the rotating
during operation diodes, and replace any
(**) defective components
(**) Caution : Internal protection may be activated (overload, open circuit, short-circuit)
INSTALLATION AND MAINTENANCE
LSA 49.1 4P
ALTERNATORS
SERVICING - MAINTENANCE
- If the bearing has turned blue or if the grease has turned black, change the
bearing.
- Bearing not properly seated.
- End shields incorrectly aligned (flanges not properly fitted).
- Air flow (intake-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
- Misalignment (coupling)
- Defective mounting or play in coupling
- Rotor balancing fault
- Alternator operating in single-phase mode (single-phase load or faulty contactor
or installation fault)
- Stator short-circuit
- System short-circuit
- Mis-paralleling
Possible consequences
- Broken or damaged coupling
- Broken or bent shaft end.
- Shifting and short-circuit of main field winding
- Fan fractured or coming loose on shaft
- Irreparable damage to rotating diodes or AVR.
Effect
The alternator builds up and its voltage is
still correct when the battery is removed.
The alternator builds up but its voltage
does not reach the rated value when
the battery is removed.
The alternator builds up but its voltage
disappears when the battery is
removed
Correct speed
Speed too low
Adjustment ineffective
If no effect : try normal / fast recovery
modes (ST2)
Voltage between E+ and E-
AREP / PMG < 10V
Voltage between E+ and E-
AREP / PMG > 15V
The voltage does not return to the rated
value.
Ref. 3007 GB - 4.33/a - 10.00
Action
Check/Cause
- Lack of residual magnetism
- Check the connection of the voltage reference to the
AVR
- Faulty diodes
- Armature short-circuit
- Faulty AVR
- Field windings disconnected
- Main field winding open circuit - check the resistance
Check the AVR connections (AVR may be faulty)
- Field windings short-circuited
- Rotating diodes burnt out
- Main field winding short-circuited - Check the resistance
Increase the drive speed
(Do not touch the AVR voltage pot. (P2) before running
at the correct speed.)
Faulty AVR
- Check the speed : possibility of cyclic irregularity
- Loose connections
- Faulty AVR
- Speed too low when on load (or LAM set too high)
- Check the speed (or LAM set too high)
- Faulty rotating diodes
- Short-circuit in the main field. Check the resistance
- Faulty exciter armature.
- Exciter winding open circuit
- Faulty exciter armature
- Faulty AVR
- Main field open circuit or short-circuited
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