Troubleshooting - WEG AG10 Series Installation, Operation And Maintenance Manual

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