12638144 Installation, operation and maintenance manual – Synchronous Alternator – AG10 line - Horizontal l 47
8
TROUBLESHOOTING
Below are listed some abnormal situations that can occur on the switch in service, as well as the correct procedure for
verification and correction.
THE ALTERNATOR DOES NOT EXCITE
ANOMALY
PROCEDURE
Interruption in the auxiliary winding circuit.
Check the union of the cables of the auxiliary winding in the connection
block extending to the connecting block the regulator and fuse.
Burned fuse.
Replace the fuse (as specified).
Residual voltage too low.
Disconnect the wires to the regulator and perform external excitation
with battery 12 to 20Vcc (negative pole in F- and positive pole in F +),
until the beginning of the excitation process.
The starting battery of
the diesel engine should not be grounded.
Drive speed is not correct.
Measure the speed and regulate it.
Interruption in the main excitation circuit.
Check the continuity of the cables F- and F +, make measurements in
all the diodes and replace defective diodes or replace the whole set.
Relay or other component of the voltage regulator
faulty
.
Replace voltage regulator.
External potentiometer for voltage adjustment
ruptured or interrupted connection.
Check the connections to terminals 11-12 and potentiometer.
Varistor of protection of the diodes (if any) is faulty.
If defective, the varistor should be replaced, or there is no a spare part,
remove it temporarily.
ALTERNATOR DOES NOT EXCITE, UP TO RATED VOLTAGE
ANOMALY
PROCEDURE
Faulty rotating diodes.
Replace the set of diodes.
Incorrect speed.
Measure the speed of the primary machine and regulate it.
Adjustment below the rated voltage.
Adjust the potentiometer in the regulator or the external one.
Supply of voltage regulator is not according to the
desired output voltage.
Verify if connections are according to the manual of voltage regulator.
IN NO LOAD, THE ALTERNATOR EXCITES UP TO RATED VOLTAGE, BUT COLLAPSES WITH THE LOAD
ANOMALY
PROCEDURE
Sharp speed decrease.
Control Diesel selector.
Faulty rotating diodes.
Replace the set of diodes.
THE ALTERNATOR, IN NO LOAD, IS EXCITED THROUGH OVERVOLTAGE.
ANOMALY
PROCEDURE
Faulty voltage thiristor of regulator.
Replace regulator.
Power transformer of regulator is defective or
incorrect.
Check voltage / operation ratio.
Supply of voltage regulator is not according to the
desired output voltage.
Redo the connections. Check the manual of the voltage regulator.
OSCILLATION ON ALTERNATOR VOLTAGE
ANOMALY
PROCEDURE
Stability improperly set
Adjust the stability of the regulator with the trimpot.
Oscillations in the speed of the drive machine.
Frequent oscillations are originating from the drive machine and need
to be eliminated.
MECHANICAL ANOMALIES
ANOMALY
PROCEDURE
Overheating of bearings.
Faulty bearing, lack of lubrication or excessive axial clearance.
Overheating in the alternator frame.
Air input or output partially clogged or hot air is returning to the
alternator, alternator overload or over excitement.
Excessive vibration.
Misalignment, faulty assembly or clearance in coupling.
Strong voltage drop with subsequent recovery:
(flashes)
Incorrect adjustment of stability, alternator operating with simple
parallelism system turned on or momentary overload.
ATTENTION
The machines included in this manual are in continuous improvement, so the information in this manual is subject
to changes without notice.
