MarelliMotori MEC-20 Manuel Utilisateur page 35

#2 - VISUAL / MULTI-METER CHECKS
CHECK A – Varistor/Capacitors
(Varistor/Capacitors)
Visual inspection:
- Check that the varistor and the capacitors are not
damaged.
Damage types may be:
1- Exploded/blown component.
2- Broken component.
Multi-meter check:
- None.
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 A.
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.
- None.
Possible failure causes:
- Mechanical damage due to impact/shock.
- Voltage exceeding 420Vrms between terminals P1 and P2 due to alternator overvoltage.
- Improper connection, which resulted in a voltage higher than 420Vrms between terminals P1 and P2.
Actions:
- Replace the AVR.
#2 - VISUAL / MULTI-METER CHECKS
CHECK B – Fuse
(Fuse)
Visual inspection:
- Check that the fuse is not broken or blown.
- Check that the fuse holder blades are tightly in place around
fuse terminals A and B.
- Check whether there is any resin and/or dirt between the fuse
holder and the fuse terminals.
Multi-meter check:
1- Remove the fuse from the fuse holder.
2- Select the resistance measurement mode on the multi-meter.
3- Connect the multi-meter probes to pins A and B of the fuse and
check that the measured resistance is < 1Ω. If it is not, the fuse has to
be replaced.
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 B.
Otherwise leave the box blank.
963857154_U
Capacitors
Varistor
A
B
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