NANO

ELECTRICAL

621

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