ENGLISH
963857101_G
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8. TROUBLE SHOOTING AND REPAIRS
8.1 Electric anomaly
TROUBLE
POSSIBLE CAUSE
REMEDY
(always to be done with the machine switched off)
The alternator will not
energise (no load voltage
below
10%
of
rated
voltage).
a) Loose connections.
b) Rotating diodes or surge suppressor
broken.
c) Excitation circuit shorted or interrupted.
d) Insufficient residual voltage
a) Check and repair.
b) Check the diodes and change in case they are open or
short circuited.
c) Check the continuity and repair.
d) Apply for a while a 12 Volt battery voltage connecting
the – terminal to – of AVR and + terminal to + of AVR by
means of a diode.
The alternator will not
energise (no load voltage
20-30% of rated voltage).
Voltage insensitive to AVR
potentiometer's rotation.
a) Fuse (on AVR’s supply line) blown.
b) Connection's cut on the exciter stator.
c) Incorrect connections of exciter stator.
a) Replace the fuse with the spare. If the fuse blows again
check if the exciter stator is short circuited. If everything
is correct, change the AVR .
b) Check the continuity and repair.
c) Reverse the two wires from the exciter stator.
Voltage lower then rated
(output voltage between 50
and 70%).
a) Speed less than rated.
b) Voltage potentiometer unset.
c) Fuse blown.
d) Faulty regulator.
e) Over excitation limitation intervention.
a) Check rpm (frequency).
b) Rotate the potentiometer until the voltage reaches the
rated value.
c) Replace the fuse with spare.
d) Disconnect AVR and replace it.
e) Re-set the potentiometer for excitation limitation (AMP)
Voltage too high.
a) Potentiometer V unset.
b) Faulty regulator.
a) Rotate the potentiometer until the voltage reaches the
rated value.
b) Replace AVR.
Unstable voltage.
a) Diesel engine rpm variations.
b) Stability potentiometer unset.
b) Faulty regulator.
a) Check rpm uniformity. Check the diesel engine
governor.
b) Act on AVR’s stability potentiometer.
b) Replace AVR.
