Ingersoll-Rand G 270, Users Manual And Maintenance Manual

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17
INSTALLATION AND MAINTENANCE
LSA 46.2 / 47.1
ALTERNATORS
SERVICING - MAINTENANCE
Ref. 2981 GB - 4.33/a - 04.00
LEROY-SOMER
4.5 - Electrical faults
4.5.1 - Checking the winding
You can check the winding insulation by performing a high
voltage test. In this case, you must disconnect all AVR wires.
Damage caused to the AVR in such conditions is
not covered by our warranty.
Fault Action Effect Check/Cause
No voltage at
no load on
start-up Connect a new battery
of 4 to 12 volts to
terminals E- and E+,
respecting the polarity,
for 2 to 3 seconds
The alternator builds up and its
voltage is still correct when the
battery is removed.
- Lack of residual magnetism
The alternator builds up but its
voltage does not reach the rated
value when the battery is removed. - Check the connection of the voltage reference to
the AVR
- Faulty diode
- Armature short-circuit
The alternator builds up but its
voltage disappears when the
battery is removed - Faulty AVR
- Field windings open circuit (check winding)
- Main field winding open circuit (check the
resistance)
Voltage too
low Check the drive speed
Correct speed
Check the AVR connections (possible AVR
failure)
- Field windings short-circuited
- Rotating diodes burnt out
- Main field winding short-circuited - Check the
resistance
Speed too low
Increase the drive speed. (Do not touch the AVR
voltage pot. (P2) before running at the correct
speed.)
Voltage too
high Adjust AVR voltage
potentiometer Adjustment ineffective Faulty AVR
Voltage
oscillations Adjust AVR stability
potentiometer If no effect : try normal / fast
recovery modes (ST2) - Check the speed : possibility of cyclic irregularity
- Loose connections
- Faulty AVR
- Speed too low when on load (or LAM set too
high)
Voltage
correct
at no load and
too low when
on load Run at no load and
check the voltage
between E+ et E- on the
AVR
Voltage between E+ and E- (DC)
AREP / PMG < 10V
- Check the speed (or LAM set too high)
Voltage between E+ and E-
AREP / PMG > 15V - Faulty rotating diodes
- Short-circuit in the main field. Check the
resistance- Faulty exciter armature. Check the
resistance.
Voltage
disappears
during
operation Check the AVR, the
surge suppressor, the
rotating diodes, and
replace any defective
components The voltage does not return to the
rated value. - Exciter winding open circuit
- Faulty exciter armature
- Faulty AVR
- Main field open circuit or short-circuited
WARNING