SWITCH-TOGGLE 9D3721 - Caterpillar

Engine: 3512C (S/N: SLM1-UP)Generator Set: 3516B (S/N: PBR1-UP) 3516C (S/N: SBJ1-UP; SBK1-UP; SBM1-UP) C175-16 (S/N: WYB1-UP)Introduction
Do not perform any procedure in this Special Instruction until you have read the instruction and until you understand all of the instruction.This Special Instruction is to provide a basic understanding of the inspection and serviceability of the 303-8189 Flexible Coupling Gp .General Description
Illustration 1 g01874779
303-8189 Flexible Coupling Gp (1) Coupling assembly (2) Cover plate (3) Silicone blocks (4) Inner member (5) Outer memberA coupling with serviceable silicone blocks is used to transmit power from the engine to the generator.
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The rotation is clockwise. (3a) Leading block (3b) Trailing blockThe power is transmitted through the leading blocks. The leading blocks are constantly under compression while the engine and the generator are running. The trailing blocks are not under compression and may rotate during engine operation. The two types of blocks will wear differently.Inspection Schedule
To ensure the reliable operation of the engine and generator, inspect the coupling during the engine top end overhaul. The overhaul schedule is defined in the Operation and Maintenance Manual. If the coupling shows excessive wear at the inspection, replace the entire coupling. If the the silicone blocks show excessive wear at the inspection, replace the silicone blocks. If the blocks are replaced, then all 24 blocks need to be replaced as a complete set.Inspection of the Coupling
In order to inspect the coupling, the generator must be removed from the engine. Remove the cover between the engine and the coupling. Remove the bolts from the coupling on the flywheel. Move the generator away from the engine. Attach a proper lifting device on the coupling. The coupling weighs 164 kg (362 lb). Unbolt the coupling from the generator and remove the coupling. Place the coupling on a flat surface. Remove the cover plate.
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Coupling with the cover plate removedNote: The blocks must remain in the original sequence in the coupling. If the original sequence is changed, shorter coupling life may occur due to uneven loading of the blocks.Mark the silicone blocks as the blocks are removed in order to keep track of the original position of the blocks. Clean the blocks and clean the cavities in the coupling with 5N-5561 Silicone Lubricant . The silicone lubricant can be used in small quantities to aid in the assembly of the coupling. Do not use a petroleum based agent. After the inspection is complete, assemble the coupling. Install the coupling on the generator. Align and install the generator on the engine.Refer to the Special Instruction, SEHS7654, "Alignment – General Instructions" and Special Instruction, REHS0177, "Alignment of the Close Coupled Two Bearing Generators" for instructions on the generator alignment.Inspection Criteria
The illustrations 4 through 6 give examples of normal coupling wear.
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Normal wear on the inner member
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Normal wear on the inner member and outer member
Illustration 6 g01875014
Excessive amount of silicone lubricantAn excessive amount of silicone fluid was used during the field assembly of the coupling shown in illustration 6. The textured pattern was created by