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ELECTRICAL
5) Armature insulation Test
Use 11O Volts AC Mains 15W bulb with 2 probes
connect as shown in fig. Bulb must not glow when
probes are connected between any one of the
commutator segment and armature core / shaft. If
the bulb glows the fault is with the insulation / ear
thing. Replace theArmature.
E. BENCH INSPECTION
1) Brush Length Check
Inspect the brushes length is of required.
A. New length -12.5mm
B. Minimum length - 6 mm
If not, renew the brushes in SETS and not
individually. If original brushes need cleaning, use
petrol moistened cloth.
2) Brush Gear Assembly Check Insulation Test
Use 110 VoltsACmains 15Wbulb with two probes.
When the probes are connected to the insul brush
box and to the earth brush box, the bulb should
not glow. If the bulb glows it is improper insulation.
Brush Gear assembly to be replaced.
3) Armature Test
Armature winding growler test:
Check the Armature on a growler tester for short
circuit and continuity of windings.
4) Commutator run-out check
Check the commutator run- out as shown in fig.
Limits should not exceed 0.3 mm. If it exceeds
the limits give a fine cut on the commutator on a
lathe, if it is not possible replace the Armature.