TP-6774 2/14a 77Section 8 Component Testing and Adjustment
8.5 Slip Rings (6EKOD/5EFKOD
Models)
Slip rings acquire a glossy brown finish in normal
operation. Do not attempt to maintain a bright,
newly-machined appearance on the slip rings. Cleaning
with a dry, lint-free cloth is usually sufficient. Use very
fine sandpaper (#00) and apply light pressure to remove
roughness. Do not use emery or carborundum paper or
cloth. Clean all carbon dust from the generator after
sanding the slip rings. If the rings are black or pitted,
remove the rotor and use a lathe to remove some of the
slip ring surface material.
8.6 Brushes (6EKOD/5EFKOD
Models)
The brushes transfer current from the ADC IId to the slip
rings. The brushes should last the life of the generator.
Abrasive dust on the slip rings, however, shortens the
life of the brushes. Excessive arcing at the brushes
could damage the ADC IId controller. Weak springs,
damaged slip rings, sticking brushes, a loose brush
holder, or poor brush contact causes arcing.
The brushes must be free to move within the holder and
be held in contact with the slip rings by the springs.
When correctly positioned, spring pressure on the brush
surface causes the b rush to wear evenly. The entire
brush must ride on the ring or arcing occurs and causes
burned rings or voltage regulator failure. Figure 8-8
shows the correct positioning of the brushes. Add or
remove shims as necessary to center the brushes on the
slip rings. Replace the brushes if they show uneven
wear or are worn to one half their original length.
Check the resistance through the brushes. Resistance
through the brushes should be low, 0.1--0.2 ohms
without meter lead resistance.
TP5867
1
2
Front View
Side View
3
New 1.9 cm (0.75 in.)
4
5
6
7
8
9
2
2
3
1. Brush holders (2)
2. Slip ring
3. Brush
4. Retainer wire
5. Shim
6. Spring
7. Brush holder
8. Correctly positioned
brush
9. Incorrectly positioned
brush
Figure 8-8 Brush Assembly
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