20
. MECCALTE ALTERNATOR TROUBLESHOOTING
Connections are interrupted
Alternator does not excite
Blown fuse
Insufficient residual voltage
No residual voltage
Replace fuse
Increase speed by 15%
For an instant apply on the (+) and
(-) terminals of the electronic regulator a
12 V battery voltage with 30 ohm resistor
in series respecting the polarities.
After being excited
alternator does no excite
Connections are interrupted
Check connection cables as per
attached drawings.
Low voltage at no load
Voltage potentiometer out of setting
Intervention of protection
Winding failure
Reset voltage
Check engine speed
Check wingings
High voltage at no load
Voltage potentiometer out of setting
Failed regulator
Reset voltage
Substitude regulator
Failed regulator
Rotating bridge failure
Substitude regulator
Check diodes, disconnect cables
Higher than rated voltage
at load
Voltage potentiometer out of setting
Failed regulator
Reset voltage potentiometer
Substitude regulator
Unstable voltage
Speed variation in engine
Regulator out of setting
Check regularity of rotation
Regulate stability of regulator by
acting on stability potentiometer
Symptom
Possible Cause
Corrective Action
Lower than rated voltage
at load
Voltage potentiometer out of setting
Intervention by protection
Reset voltage potentiometer
Current to high, power factor lower than
0.8;
Speed lower than 4% of rated speed
18
