D346 MARINE ENGINE Caterpillar

Every 500 Service Meter Units

Inspecting Slip Rings-SRCR Only

1. Remove the three lower panels from the rear of the generator housing.

2. Inspect the color of each slip ring.

The color may be shiny copper, straw, chocolate or black. The important thing is the color must be uniform to indicate a satisfactory condition.

3. If a ring contains blotches of green, blue or black, clean the ring with a cleaning solvent that does not leave an oily film such as Naptha.

Show/hide table

Do not use gasoline or carbon tetrachloride. The vapors from carbon tetrachloride can be extremely harmful when inhaled. Either solvent will dissolve insulation.

4. Inspect each ring for pitting, roughness, or eccentric wear. If any of these conditions are present, contact your Caterpillar dealer; the rings must be reconditioned.

5. If pitting is found, determine if the cause is (a) or (b):

a. Check the rating on the generator nameplate. The generator load must be within this rating. Determine if the generator may have been operated in an overload condition.

b. Check the brushes for incorrect spring tension.

Each brush must move freely within its holder and have enough spring load to prevent brush flotation.

Using a small spring scale, calibrated in ounces, lift each spring and check the spring tension for each brush.

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.

Every 2000 Service Meter Units

Lubricate Rear Bearing-SRCR and SR4

1. Remove the two lower panels from the rear of the generator housing.

2. Remove the upper and lower grease fitting plugs.

3. Install a grease fitting in the upper threaded hole.

4. Lubricate with grease until clean lubricant appears at the lower threaded hole.

Use Multipurpose-type Grease (MPG). NLGI No. 2 Grade is suitable for most temperatures. Use NLGI No. 1 or 0 Grade for extremely low temperatures.

5. Install the lower plug. Wipe off excess grease.

6. Remove the fitting from the upper threaded hole.

7. Start the engine and allow the grease to expand.

8. Stop the engine. Install the plug in the lower hole and wipe off excess grease.

9. Install the two panels.