HEAVY DUTY ALTERNATORS
2.
Check rotor coil resistance by connecting the
ohmmeter across the two slip rings (See Figure
19). The resistance of the rotor should be within
the following limits:
2312JB
4.9-5.5 Ohms
2512JB
2.3-2.7 Ohms
2612JB
2.3-2.7 Ohms
2812JB
1.9-2.3 Ohms
2912JB
1.9-2.3 Ohms
Figure 19 - Rotor Coil Resistance Test.
Discard rotors whose resistance values differ
significantly
from
these
figures.
Before
condemning a rotor for an open coil, check the
solder joints at the slip ring leads, as a poor
connection at either of these leads will test the
same as an open coil. If the proper resistance is
not obtained after resoldering these connections,
discard the rotor.
STATOR TEST
Use a Wheatstone Bridge or an ohmmeter capable of
measuring 1/1000 ohm to check stator for grounds and
for phase resistance. Stator is OK when no circuit is
present between lamination and each of the three leads,
and
resistance
readings
across
each
phase
are
approximately the same. It is suggested that stators be
"high pot" tested by a qualified electrical shop to help
identify
borderline
stators:
Stator
must
be
disconnected from alternator to perform these tests
(See Figure 20).
Defective stators or ones with damaged or charred
windings must be discarded regardless of how they test.
Several stators are available which can be used as
service replacements on these alternators. The part
numbers of these stators will be listed in the appropriate
parts list.
SLIP RING REPLACEMENT
The slip ring assembly used in these alternators is of
extremely sturdy construction and will seldom require
replacement. If it should become damaged in some way,
such as dropping the rotor, it may be replaced in the
following manner.
Figure 20 - Stator Test.
1.
Unsolder the slip ring leads and lift them clear of
the eyelets which serve to retain them to the
rotor coil leads. Do not lose or damage the
eyelets (See Figure 21).
Figure 21 - Disconnecting Slip Ring Leads.
2.
With a suitable puller, the slip ring assembly may
now be pulled from the shaft (See Figure 22).
CTS-4043A - Chapter II - Page 9
