Mechanical Defects; Electrical Faults - SDMO R 340 U User And Maintenance Manual

LEROY-SOMER

4.4 - Mechanical defects

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

4.5 - Electrical faults

Fault Action
Connect a new battery
No voltage of 4 to 12 volts to
terminals E- and E+,
at no load on
start-up respecting the polarity,
for 2 to 3 seconds
Voltage too
Check the drive speed
low
Voltage too Adjust AVR voltage
high potentiometer
Adjust the
Voltage
AVR stability
oscillations
potentiometer
Voltage
Run at no load and
correct at no
check the voltage
load and too
between E+ and E- on
low when on
the AVR
load
Check the AVR, the
Voltage
surge suppressor,
disappears
the rotating diodes, and
during
replace any defective
operation
components
12
Installation and maintenance
LSA 46.2 - 4 POLES
ALTERNATORS
- 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)
- Check the end shield alignment (flange 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 (Engine - Alternator)
- Phase imbalance
- Stator short-circuit
- System short-circuit
- Mis-paralleling
Possible consequences:
- Broken or damaged coupling
- Broken or bent shaft extension
- Shifting and short-circuit of revolving field winding
- Fan fractured or coming loose on shaft
- Irreparable damage to rotating diodes, AVR, surge suppressor
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 or fast stability
modes (ST2)
Voltage between E+ and E- (DC)
SHUNT / AREP / PMG < 10V
Voltage between E+ and E-
SHUNT / AREP / PMG > 15V
The voltage does not return to the
rated value
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 open circuit (check winding)
- Revolving field coil open circuit (check the resistance)
Check the AVR connections (AVR may be faulty)
- Field windings short-circuited
- Rotating diodes burnt out
- Revolving field coil 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 AVR LAM set too high)
- Check the speed (or AVR LAM set too high)
- Faulty rotating diodes
- Short-circuit in the revolving field coil. Check the resistance.
- Faulty exciter armature. Check the resistance.
- Exciter winding open circuit
- Faulty exciter armature
- Faulty AVR
- Revolving field coil open circuit or short-circuited
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3856 en - 2011.01/ h