MarelliMotori MEC-20 Manuel Utilisateur page 38

Check result:
- If the result of all the above checks has been positive, tick the ok box in section #2 of the report form,
Check E.
Otherwise leave the box blank.
In case of component failure:
Possible effects on regulation:
- The alternator output voltage is lower than the rated voltage and equal to the residual one.
- You cannot set the proper value using the VOLT trimmer.
- The alternator output voltage is higher than the rated voltage.
- You cannot set the proper value using the VOLT trimmer.
Possible failure causes:
- Mechanical damage due to impact/shock.
- The alternator output voltage is higher than the rated voltage.
- You cannot set the proper value using the VOLT trimmer.
- Not enough contact between the AVR terminals and the FASTON connectors, resulting in sparks and
voltage peaks.
Actions:
- Replace the AVR.
#2 - VISUAL / MULTI-METER CHECKS
CHECK F – IGBT
Visual inspection:
- Check that the IGBT shown in the figure is not
damaged.
Possible damage types are:
1- IGBT blown.
2- IGBT broken.
Multi-meter check:
1- In the multi-meter,
measurement mode.
2- Connect the multi-meter probes to terminals - and
Q of the AVR.
Expected values are:
COM probe on Q: 100 to 150kΩ.
COM probe on -:100 to 150kΩ.
If any of the above measurements is not met, the IGBT is
damaged.
Check result:
- If the result of all the above checks has been positive, tick the ok box in section #2 of the report form,
Check F.
Otherwise leave the box blank.
In case of component failure:
Possible effects on regulation:
- The alternator output voltage is lower than the rated voltage and equal to the residual one.
You cannot set the proper value using the VOLT trimmer.
- The alternator output voltage is higher than the rated voltage.
You cannot set the proper value using the VOLT trimmer.
963857154_U
select the resistance
IGBT
38