Troubleshooting - Fiat 411 R Service Manual

Trouble-sh00i1'fiQ- Q
The various cases which may occur during the operation of the control box are the following:
A - Low charging rate with a fully charged battery.
This is the condition of a generator-control box system working correctly.
B - High charging rate with a fully charged battery.
This condition indicates that the voltage regulator does not limit the output as it should because a high
charging rate not only damages the already iuiiy~chargecl batteries, but also the equipment oi the system.
The causes are the following:
a} high voltage regulator setting;
b) detective voltage regulator windings or additional resistance (7, Fig. 159};
c) short circuit across the generator positive terminal and field winding which prevents the current from
passing through the regulation resistance at voltage regulator contacts opening;
cl) insuiiicfeni connection between control hex and generator through mass;
e) high temperature which reduces the battery electromotive force reacting to the charge, so that the
battery absorbs a high charging current even if the regulator set voltage is normal;
l') self-welding of the voltage and current regulator contacts.
in all the above cases, excluding case e), one of the two following conditions will occur on disconnecting
the cable 67 from generator to control box:
1) Output remains high (trouble covered by point c).
2) The output stops completely (the trouble lies in the control box which should be checked as to points
a), b), d) and i).
Note ~ If the generator output remains high even after a long period oi charging but neither trouble nor
high temperature show up in the control box. the battery is old or maintenance wrong. It does not absorb
any more current, the voltage does not rise above a certain value and the generator current does not decrease.
C ~ Discharged battery and high charge.
Condition of correct operation of the generator and control box unit.
D - Discharged battery and low or no charging rate.
This condition is due to the following:
a] burnt control box fuse » b) interruption of the additional resistance of the cut-out relay shunt winding
(H, Fig. 159} - c) loose connections, detective cables - d) detective battery - e) charging system high
resistance - t) voltage or current regulator low voltage setting - g) voltage or current regulator oxidized
contacts - h) generator trouble.
Should the above condition be caused by the failure of the additional resistance (ii, Fig. 159} repiace it.
ii on the other hand, it is caused by fuse failure, search tor the cause of tuse burning before replacing it.
The reason may be found among the toliowing:
— the out-out relay contacts do not open as the engine stops;
—~ short circuit;
-— reversed generator polarity.
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