SDMO R44C3 User And Maintenance Manual page 181

LeRoY-SoMeR
4.4 - Mechanical defects
Fault
Excessive overheating of one or both
bearings (temperature > 80 °C on the
Bearing
bearing retainers with or without abnormal
noise)
Excessive overheating of alternator frame
Temperature (more than 40 °C above the ambient
abnormal 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
Connect between E- and
No
voltage E+ a new battery of 4 to
12 volts, respecting
at no load
on start-up the AVR polarities, 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
the voltage between E+
at no load and
and E- on the AVR
too low when on
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 43.2 / 44.2 - 4-poLe
ALTeRNAToRS
- If the bearing has turned blue or if the grease has turned black, change the
bearing.
- Bearing not properly seated.
- End shields misaligned (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
- 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/rapid recovery
modes (ST2)
Voltage between E+ and E-
SHUNT < 20 V - AREP/PMG < 10 V
Voltage between E+ and E-
SHUNT > 30 V - AREP/PMG > 15 V
The voltage does not return to the rated
value
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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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