Page 162 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

Fig 1 Fig 2

Fig 3

TASK 4: Test the armature and commutator

1 Test armature for ground (Fig 1)
2 Using an ohmmeter test for continuity between the commutator (2) and armature core (1).The ohmmeter will
indicate infinite resistance if the insulation is in sound condition.
3 Test for open circuit (Fig 2)

Fig 1 Fig 2

4 Check for continuity between each pair of adjacent commutator segments, using an ohmmeter.

5 If there is any discontinuity the ohmmeter needle will not deflect. Replace the armature assembly.
6 Check commutator run out (Fig 3)
7 Place the armature between two ‘V’ blocks.
8 Using a dial gauge check the commutator for run out by slowly rotating it by hand.
9 Correct it on lathe if required.

10 Check commutator diameter

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CITS : Automotive - Mechanic Diesel - Exercise 9.2