Case 580SR Service Manual page 983

www.maskinisten.net
STATOR -CHECKING THE INSULATION
Z Check the insulation of each winding with respect
to the alternator casing. There must not be any
continuity between the winding and the casing. If
the ohmmeter (2) indicates any value other than an
open circuit, replace the entire stator (1).
CHECKING THE ROTOR
Before checking the rotor components, inspect the
slip rings to make sure that they are in good condi-
tion.
Z Check that the slip rings are clean and smooth. If
necessary, clean them with a cloth soaked in gaso-
line. If the slip rings are burnt, scrape them with
very fine sandpaper (do not use emery cloth) and
wipe them.
NOTE: make sure that the sandpaper is sufficiently
fine in order to obtain a perfect finish of the slip ring
surfaces and avoid premature wear of the brushes.
Z If the slip rings are excessively worn, replace the
rotor.
ROTOR - CHECKING THE CONTINUITY OF THE
FIELD WINDING
Z Connect an ohmmeter (3) between the two slip
rings (2). The resistance must be 2.6 ohms at
20 °C.
If the resistance is incorrect, replace the rotor (1).
SECTION 55 - ELECTRICAL SYSTEM
Copyright ©
155