Nanni Q2400 Series, Руководство пользователя

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96
S08 ALTERNATOR
ROUTINE MAINTENANCE
Assessment of windings conditions after long
periods of storage or inactivity.
Type of intervention Operator
PPE to wear Periodicity
Every 2500 hours of use
Materials and equipments
“Megger” Tester or similar to 500V in continuous voltage.
DANGER!
Disconnect the alternator from the power supplies. The
drive motor must be off and unplugged from its power
supplies
Measuring the insulating earth resistance can assess the
condition of the windings.
This measurement can be carried out with a “Megger”
device, or similar, with a 500V direct-current voltage.
NOTE!
It is very important to disconnect the voltage regulator
(fig. a), the rotating diode bridge (fig. b) and the radio
interference filter (fig. c), as well as any other device
connected to the windings to be checked, before carrying
out the measurement.
fig a
fig a
fig a
The figure resulting from the measurement of the
windings’ earth resistance must be over 1MΩ.
Should the figure be smaller than the above-mentioned
one, the windings must be adequately dried up. This can
be done by directing a jet of hot air of about 50-60°C
into the generator’s air inlets or outlets; alternatively,
the stator’s windings can be electrically connected and
a voltage can be passed through them by means of a
direct current power supply. The amount of current in the
windings depends on the generator size, even though it
must be fixed according to the nominal values stated on
the plate.