NANO

644 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.