MCi Crusader II 1989 Maintenance Manual page 239

Date 1-1-89
page. __
1_-_19 _ _ _
MC-9 MAINTENANCE MANUAL
14 Grounds - If the motor has one or more coils normally
connected to ground. disconnect the ground connections dur-
ing this check. Connect one lead of the 110-volt test lamp to the
field frame and the other lead to the field connector. If the lamp
IIghts. at least one field coil Is grounded which must be repaired
or replaced. This check cannot be made
If
the ground connec-
tion cannot be disconnected.
15. Opens Connect test lamp leads to ends of field coils.
If
lamp does not light. the field coils are open.
Field coils can be removed from the field frame assembly by
using a pole shoe screwdriver. A pole shoe spreader may also
bl? used to prevent distortion of the field frame. Careful installa-
i,or of the field coiis ,s necessary to prevent shorting or ground-
,ng of the field coI I s as the pole shoes are tightened into place.
Where the pole shoe has a long lip on one side and a short lip
OP
tne other. the long IIp should be assembled in the direction of
armature rotation so It becomes the trailing (not leading) edge of
,he pole shoe
SOLENOID CHECKS - A basic three-terminal solenoid
circuit is shown in A of Figure
7-39.
and a four-terminal
solenoid circuit is shown in
8.
With all other leads
disconnected, the solenoid windings can be checked by
making test connections as covered below.
THREE-TERMINAL SOLENOID:
CAUTION: To avoid excessive heating. in
the following tests. leave the pull-in wind-
ing connected no more than 10 seconds at
a time. The current will decrease as the
heating increases.
Hold-in winding
grounded internally
- 3 terminals.
Solenoid
ha■
ground
return terminals - 4
terminals.
Figure 7-39. Solenoid Circuits.
~
6 As shown In figure 7 -40. make connections to the
·s ..
terminal and a clean metal ground If needed. use the carbon
'"'- o,!e to decrease the battery voltage to the value specified m the
"foI,ow1ng table and compare the ammeter reading with. the
hoId-,n w1nd1ng specifications A high reading indicates a
defective winding ishorted or grounded hold-m or a grounded
pu•l-,n). and a low reading ,nd1cates excessive resistance
SOLENOID TEST SPECIFICATIONS
Pull-In Windows
Hold-In
Windows
Solenoid
Test Voltage Current Dra\llf Test Voltage
Current Ora~
7G-1-84•
5 8 5-10 0 20
110-150
7G-6-25 ..
5 9.0 11 5 20
68 Max
• Used With 42MT Starter (7G-1-391
•• Used With 40MT Starter (7G-1-1) and 50MT (7G-1-38)
Figure 7-40. Checking.Solenoid Hold-In Winding.
i_ _ _ _ _
Figure 7-41. Testing Pull-In Winding On Solenoid.
17 To check the pull-in winding connect from the solenoid
switch terminal to the solenoid motor terminal 1figure 7-411
Compare with the puII-In winding spec1f1cat1on A high reading
indicates a shorted pull• ,n wmd,ng. and a low read, ng indicates
excessive resistance
A