PLATE 4234972 - Caterpillar

Description
The assembly for the rotor position sensor (RPS) is located on the top of each of the flywheel assemblies. The flywheel assemblies are mounted to the upper bearing. The board for the rotor position sensor generates the rotor speed feedback that is used by the system controller. The feedback is used in order to derive the gate signals for the flywheel inverter modules. The board also generates the signals that are used to monitor the levels of vibration in the flywheel.3.0+ hardware uses an "Optical RPS" assembly in place of the previous unit. The "Optical RPS " assembly is made up of three major components: the "Comm/Accel Fiber Optic" board, the "RPS Fiber Optic "cable and the "Comm/Accel LED" board.The "Comm/Accel Fiber Optic" board interfaces to the "Comm/Accel LED" board and to the flywheel interface board. The "Comm/Accel Fiber Optic" board has two accelerometers that measure the horizontal and vertical vibrations . The measurements for vibration are sent to the flywheel interface board.The rotor position sensor detects rotation of the rotor. Also, the rotor position sensor consists of a coupled light beam that is interrupted by a slotted rotor. The "Comm/Accel LED" board provides the light source (LED) that is picked up by the rotor position sensor.The "Comm/Accel Fiber Optic" board converts the light signal to an electrical signal. The electrical signal is transmitted to the flywheel interface board.The assembly for the magnetic RPS sensor can be upgraded to the assembly for the optical RPS sensor with a retrofit kit. Refer to Systems Operation, Testing and Adjusting, RENR9988, "Attachments" for further information.Removal Procedure
Refer to Systems Operation, Testing and Adjusting, RENR9988, "Internal Component Preremoval Steps (Flywheel Cabinet)" in order to shut down the system and gain access to internal components.
Electrostatic discharge can damage integrated circuits or semiconductors if you touch bus connector pins. When not in use, keep the module in a static-shield bag. Follow these guidelines when you handle any module:Touch a grounded object to discharge static potential.Wear an approved wrist-strap grounding device.Do not touch the bus connector or connector pins.Do not touch circuit components inside the module.If available, use a static-safe work station.
Remove the SAE O-ring plug in order to relieve vacuum in the flywheel housing.
Clean the SAE O-ring plug and threads. Apply a small amount of 6V-2055 Grease to the O-rings.
Replace the SAE O-ring plug. Tighten the SAE O-ring plug to appropriate specifications.Refer to Special Instruction, REHS8801 for information about tightening the SAE plugs for certain flywheel uninterruptible power supply units.
Illustration 1 g01278291
"Optical RPS" Assembly (1) RPS fiber optic cable (2) Comm\Accel fiber optic board (3) J3 ribbon cable (4) O-Ring Groove (5) Comm\Accel LED Board (6) FO Cable Bracket (7) RPS Base Plate (8) O-Ring
Disconnect the "J3" ribbon cable (3) from the "Com/Accel Fiber Optic" board (2) . Refer to Illustration 1.
Illustration 2 g01287637
(9) Mounting bolt
Use a 7/64 inch hex key to remove the three mounting bolts (9) that hold the RPS assembly to the upper bearing. Refer to Illustration 2.
Lift the assembly for the rotor