Starting System Bench Tests; Armature Open Circuit Test; Armature And Field Grounded Circuit Test - Ford LSG 875 Service Manual

5-04
STARTING SYSTEM
5-04
TESTING (Continued)
BENCH TESTS
STARTER NO-LOAD TEST
The starter no-load test will uncover open or Grounded field windings can be detected by
shorted windings, rubbing armature, and bent ar-
making the connections as shown. If the voltmeter
mature shaft.
indicates any voltage, the field windings are
grounded.
The starter can be tested, at no-load, on the test
bench only.
Make the test connections as shown. The start-
er will run at no-load. Be sure that no current is
flowing through the ammeter (rheostat at max-
imum counterclockwise position). Determine the
exact reading on the voltmeter.
BATTERY
STARTER
J1087-1G
DO NOT CONNECT
LEAD TO BEARING
JUMPER LEAD
VOLTMETER
EGATIVE LEAD
i
\ x.
VOLTMETER POSITIVE LEAD
TOUCH TO COMMUTATOR
J1088-1F
0
A KEEP BOTH FIELD BRUSHES
AND HOLDING COIL GROUND
LEAD AWAY FROM FRAME
I
6) CONNECT VOLTMETER
JUMPER L
ARMATURE OPEN CIRCUIT TEST
An open circuit armature may sometimes be
detected by examining the commutator for evi-
dence of burning. A spot burned on the com-
mutator is caused by an arc formed every time the
commutator segment, connected to the open cir-
cuit winding, passes under a brush.
ARMATURE AND FIELD GROUNDED
CIRCUIT TEST
This test will determine if the winding insulation
has been damaged, permitting a conductor to
touch the frame or armature core.
TER
@DISCONNECT HOLDING colL
0
c INSERT INSULATOR
GROUND LEAD (FINE WIRE
BETWEEN CONTACTS
INSIDE FRAME)
J3566-1 A
To determine if the armature windings are
grounded, make the connections as shown. If the
voltmeter indicates any voltage, the windings are
grounded.