GMC C Series 1993, Руководство по ремонту

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SP STARTER MOTORS 6 P M
7. Brushes for wear. If the brushes are worn to half
the size of a new brush, replace the brushes. On
the SD-260, the brushes and brush holders are an
integral part of the frame and field assembly, so the
assembly must be replaced.
8. Brush holders for dirt or damage.
• Make sure that the brushes are not binding in
the holders.
9. Brush springs for distortion or discoloring. If the
springs are weak, bent, or discolored, replace
them. On the SD-260, replace the frame and field
assembly.
10. Field coils.
• Look for burned or damaged insulation, dam­
aged connections or loose poles. Replace the
field coils if their condition is doubtful. On the
SD-260, replace the field and frame assembly.
11. Field coils for grounds.
• Connect a test lamp between the field frame
and the field connector (figure 15). Make sure
the brush ends do not contact the field frame.
— If the test lamp lights, the field coils are
grounded and must be repaired or replaced.
On the SD-260, the field and frame assem­
bly must be replaced.
12. Field coils for opens.
• Connect a test lamp between the field connec­
tor and each of the positive brushes.
— If the test lamp does not light at both
brushes, the field coils are open.
13. Field coils for shorts.
• Shorts are indicated by poor motor performance
after everything else has been checked out. On
the SD-260 starter motor, the coils cannot be
replaced separately because of the integral
frame construction. The frame and field assem­
bly must be replaced. To replace the field coils
on the SD-300, a pole shoe spreader and pole
shoe screwdriver should be used. Care should
be exercised in replacing the field coils to pre­
vent grounding or shorting them as they are
tightened into place.
14. Drive assembly (clutch) by turning the drive pinion
in the cranking direction.
• If the drive pinion turns roughly or slips in the
cranking direction, replace the complete
over-running clutch assembly.
15. Solenoid for grounds using a self-powered 12 volt
test lamp (figure 16).
— Connect the test lamp between the BAT termi­
nal and the case. The lamp should not light
(terminal should not be grounded).
— Connect the test lamp between the “S" terminal
and the case. Then connect the test lamp
between the “M" terminal and “S" terminal or
“M" terminal and the case. The lamp should
light.
— If the solenoid does not pass these checks,
replace it.
16. Hold-in winding and pull-in winding.
• With all the leads disconnected from the sole­
noid, make the test connections as shown in
figure 17.
F i g u r e 1 5 — C h e c k i n g t h e F i e l d C o i l f o r G r o u n d s
w in d in g , d o n o t le a v e th e w in d in g e n e rg iz e d
m o re th a n 15 s e c o n d s . T h e c u n e n t d ra w w ill
d e c r e a s e a s t h e w in d in g t e m p e r a t u r e
In c re a s e s .
• Turn the switch on and adjust the carbon pile to
lower the battery voltage to the value shown in
“Specifications” at the end of this section.
• Note the ampere reading; a high reading indi­
cates a shorted or grounded winding, and a low
reading indicates excessive resistance.
— The windings resistance can be read directly
using a digital ohmmeter that can measure
tenths of art ohm.
— The cOil resistance can be determined by
dividing the voltage by the current (am­
peres) listed in “Specifications’' at the end of
this section.