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ELECTRICAL
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ELECTRICAL
12. BENCH INSPECTION
After dismantling the unit conducts the
following checks
Brush check
Minimum required Brush Length: 7.5 mm
It the brushes are below the minimum required
length renews the brushes in sets not individually.
De’ solders the brush lead assy. Insert New brush
assembly and solder. Make sure that the brushes
move freely inside the brush box.
•
Slip ring check
Clean slip ring surface with a fine piece of cloth
and ensure that the surface is smooth and clean.
If the surface is very rough and cannot be polished,
replace the rotor assembly. There should not be
any trace of oil or grease on the slip ring surface.
•
Bearing check (SRE &DE)
Bearing should rotate freely without any excessive
play. If play is observed, the bearings should be
replaced.
•
Rotor assembly check :
Resistance Check: Use ohmmeter 0-10 ohm range
and connect as shown in fig. Connect the probes
of the meter to the slip ring. The value should be
2.47 – 2.73 ohms at 20°C . If value is outside this
limit, change the rotor assembly.
•
Rotor ground test