GEAR-BEVEL 8U3376 - Caterpillar

3000 Frame Diode Assembly Remove and Installation
Diode Removal
Ensure that the generator is isolated from any other power source or residual power sources.
Loosen all of the mounting bolts for the cover (3). Mounting bolts (1) and (2) are an example. A suitable lifting device may be required in order to remove the cover (3). Refer to Illustration 1.
Illustration 1 g01926493
Typical example of an earlier style of end bracket cover.
(1) Mounting bolt at the 12 o'clock position
(2) Mounting bolt at the 3 o'clock position
(3) Diode assembly cover
The cover must tilt slightly in order to install two link bracket assemblies (5). Install a suitable lifting device (6) on the link brackets. Refer to Illustration 2. Apply enough lift in order to allow the lifting device to support the weight of the cover (3). Remove the remaining mounting bolts for the cover (3). The cover weights approximately 50 kg (110 lb).
Illustration 2 g01926713
Label all of the wires (9) and (10) that are connected to each rectifier module (8) and (11).
The following sub steps apply to later models for removal of the end bracket cover.
Illustration 3 g03451063
Typical example of a later model exciter cover
(7) Bolt to be loosened
A metric Allen wrench is required for the bolts used for the cover. Loosen the cover bolts that are located at the 10, 12, and 2 o'clock positions.
Loosen the bolts (7) located at 3 o'clock and 9 o'clock positions. Note: The cover that is shown in Illustration 3 has two sections, upper and lower. There is no need to separate the two sections, only loosen the bolts that hold the sections together.
Remove the exciter cover from the generator.
Illustration 4 g01926833
(8) Diode block
(9) Leads to be removed
(10) Leads to be removed
(11) Diode block
(12) Varistor
Remove the leads, (9) and (10), that are connected to each diode block (8) and (11). Note: There is no need to remove the leads (16) that are wired between the diode blocks and the varistor. The diode assembly is replaceable, however, the individual diode blocks are not replaceable.
Remover the four mounting bolts (15) that are for the diode assembly plate (18). The diodes, varistor, and the mounting plate (18) are removed as a single assembly.
Illustration 5 g01946484
(15) Mounting bolts for the diode assembly mounting plate
(16) Leads that can be left connected
(18) Diode assembly mounting plate Diode Installation
Ensure that the wire insulation to the rectifier assembly has not been damaged.
Illustration 6 g01946559
Feed the wires for the rectifier assembly through the holes (17) that are in the diode assembly mounting plate (18).
Install the leads that were removed from each diode block. Note: Ensure that a star washer is placed first on each post.
Properly secure the wiring with cable ties. Refer to Illustration 5.