Starter Motor: Testing and Inspection
INSPECTION1. ARMATURE
1. Check commutator for any sign of burns of rough surfaces or stepped wear. If wear is of a minor nature, correct it by using sand paper.
2. Run-out test
Check the commutator run-out and replace if it exceeds the limit.
3. Depth of segment mold Check the depth of segment mold.
4. Armature short-circuit test
Check armature for short-circuit by placing it on growler tester. Hold a hacksaw blade against armature core while slowly rotating armature. A short-circuited armature will cause the blade to vibrate and to be attracted to core. If the hacksaw blade is attracted or vibrates, the armature, which is short-circuited, must be replaced or repaired.
5. Armature ground test
Using circuit tester, touch one probe to the commutator segment and the other to shaft. There should be no continuity. If there is a continuity, armature is grounded.
Replace armature if it is grounded.
2. YOKE
Make sure pole is set in position.
3. OVERRUNNING CLUTCH
Inspect teeth of pinion for wear and damage. Replace if it damaged. Rotate pinion in direction of rotation clockwise). It should rotate smoothly. But in opposite direction, it should be locked.
CAUTION: Do not clean overrunning clutch with oil to prevent grease from flowing out.
4. BRUSH AND BRUSH HOLDER
1. Brush length
Measure the brush length and replace if it exceeds the service limit.
Replace if abnormal wear or cracks are noticed.
5. SWITCH ASSEMBLY
Be sure there is continuity between terminals S and M, and between terminal S and ground. Use a circuit tester set in "ohm").
Also check to be sure there is no continuity between terminal M and B.
2. Brush movement
Be sure brush moves smoothly inside brush holder.
3. Brush spring force
Measure brush spring force with a spring scale. If it is less than the service limit, replace brush spring.
6. SWITCH ASSEMBLY OPERATION
1. Connect terminal S of switch assembly to positive terminal of battery with a lead wire, and starter body to ground terminal of battery. Pinion should be forced endwise on shaft.
CAUTION: With pinion forced endwise on shaft, starter motor can sometimes rotate because current flows, through pull-in coil, to motor. This is not a problem.
2. Disconnect connector from terminal M, and connect positive terminal of battery and terminal M using a lead wire and ground terminal to starter body.
In this test set up, pinion should return to its original position even when it is pulled out with a screw-driver.
7. PINION GAP
1. With pinion forced endwise on shaft, as outlined in step (1) before
2. If motor is running with the pinion forced end-wise on the shaft, disconnect connector from terminal M of switch assembly and connect terminal M to ground terminal of battery with a lead wire. Next, gently push pinion back with your fingertips and measure pinion gap.
3. If pinion gap is outside specified range, remove or add number of adjustment washers used on the mounting surface of switch assembly until correct pinion gap is obtained.
8. PERFORMANCE TEST
The starter should be submitted to performance tests whenever it has been overhauled, to assure its satisfactory performance when installed on the engine.
Three performance tests, no-load test, load test, and lock test, are presented here; however, if the load test and lock test cannot be performed, carry out at least the no-load test.
For these performance tests, use the circuit shown in figure.
1. No-load test
With switch on, adjust the variable resistance to obtain 11 V, take the ammeter reading and measure the starter speed. Compare these values with the specifications.
No-load test Standard):
Voltage / Current 11 V/90 A or less
Rotating speed
- MT vehicles 2,800 rpm or more
- AT vehicles 2,400 rpm or more
2. Load test
Apply the specified braking torque to starter. The condition is satisfactory if the current draw and starter speed are within specifications.
Load test Standard):
- MT vehicles
Voltage / Load 7.5 V / 8.73 N.m 0.89 kgf-m, 6.4 ft-lb)
Current / Speed 300 A / 890 rpm or more
- AT vehicles
Voltage/Load 7.7 V/ 16.00 N.m 1.63 kgf-m, 11.8 ft-lb.
Current/Speed 400 A max. / 740 rpm or more
3. Lock test
With starter stalled, or not rotating, measure the torque developed and current draw when the voltage is adjusted to the specified voltage.
Lock test Standard):
- MT vehicles Voltage / Load 4 V / 780 A or less
Torque 15.7 N.m 1.60 kgf-m, 11.6 ft-lb. or more
- AT vehicles
Voltage / Current 3.5 V / 940 A or less
Torque 28.9 N.m 2.95 kgf-m, 21.3 ft-lb. or more