SR 4 AND SRCR GENERATORS - OPERATION & MAINTENANCE Caterpillar

a. If spring tension is less than shown in the chart: Push the spring forward one notch in the retainer clip. Check the spring tension.

b. If the spring tension is greater than shown in the chart: Release the spring by one notch. Check the spring tension.

c. If the spring tension is less than shown in the chart and the spring is in the forward notch, remove the brush and check the brush length.

Removing and Installing Brushes - SRCR Only

1. Release the spring from the retainer.

2. Disconnect the lead wire of the brush.

3. Remove and inspect the brush. If the brush length is less than the minimum shown or if badly pitted, install a new brush.

4. Connect the lead wire of the brush.

5. Place the brush in the brush holder. Be sure the brush moves freely in the holder.

6. Cut a strip of "00" sandpaper the width of the brush.

Never use emery cloth for this purpose. Emery contains small metallic particles which can damage the copper rings.

7. Place the sandpaper between the brush and slip ring with the abrasive side of the sandpaper against the brush.

8. Place the spring in the middle notch of the retainer.

9. Slowly pull the sandpaper from beneath the brush.

10. Remove all dust with a suction hose. If suction is not available, use a maximum air pressure of 30 psi (2 kg/cm²). Do not use metal tips.

11. Check brush tension and adjust if necessary.

12. Install the three rear panels that were removed.