Remove and Install the AC Precharge Circuit Breaker - Frame 8

Replace the frame 8 AC precharge circuit breaker with kit catalog number 20-750-MACPCCB-1K0. Follow these steps to remove and install the AC precharge circuit breaker.
IMPORTANT: The circuit breaker weights 11.0 kg (24.25 lb). It is recommended that two people complete these steps to remove the circuit breaker from the module.
  1. Review the product advisories in Before You Begin.
  2. Remove power from the system.
  3. Open the enclosure door.
  4. Remove the protective guard.
  5. IMPORTANT: The minimum inside bend radius for fiber-optic cable is 50 mm (2 in.). Any bends with a shorter inside radius can permanently damage the fiber-optic cable. Signal attenuation increases as inside bend radius is decreased.
    fiber-optic cable bend radius example
  6. Without bending the cable to a radius less than 50 mm (2 in.), remove the fiber-optic cable from the transceiver in the ACP port on the AC precharge control circuit board.
  7. Open the transceiver latch and pull the transceiver out of the connector on the board. Retain the transceiver as a spare part.
    TIP: If the latch is obstructed and you cannot use your fingers to open it, use a small, screwdriver or other long, narrow tool to open the latch.
    example of how to remove the fiber transceiver from a fiber-optic port
  8. Cut and remove the tie wraps that secure the wire harnesses that is connected to the AC precharge control circuit board.
  9. Loosen the two 5 x 12 mm slotted-Torx screws that secure the circuit board panel to the AC precharge module chassis or enclosure side sheet and slide the panel out of the chassis as far as possible.
    example of how to remove the frame 8…15 AC precharge circuit board assembly
  10. Disconnect these wire harness connectors from the connectors on the AC precharge circuit board:
    • P1 from J1
    • P2 from J2
    • P3 from J3
    • P4 from J4
    • P5 from J5
    • P6 from J6
    • P7 from J7
    • P11 from J11
    • P12 from J12, if present
  11. example of the AC precharge circuit board connections layout
  12. Disconnect the wires from the AC precharge contactor terminals L1, L2, and L3 (top).
  13. Disconnect the wires from the AC precharge contactor terminals A1 and A2 (top).
  14. Disconnect the wires from the fused disconnect switch terminals R/L1, S/L2 and T/L3.
    example of the AC precharge contactor and fused disconnect connections in a frame 8 AC precharge module
  15. Loosen the set screw on the right-most DIN rail cap and remove the cap.
  16. Remove the fused disconnect, terminal block, and AC precharge contactor from the DIN rail.
    example of how to remove the fused disconnect from the frame 8 Ac precharge module
  17. Remove the M4 x 10 mm slotted-Torx screw from the mounting bracket.
  18. TIP: As you remove the bracket, push the three fused disconnect wires through the grommet in the bracket.
  19. Remove the five M5 nuts that secure the mounting bracket to the AC precharge module chassis and remove the bracket.
    example of how to remove the AC precharge components mounting panel from the frame 8 AC precharge module
  20. Disconnect the wires from the terminal blocks on the top of the circuit breaker; U1, U2, 95, 98, R2, R1, C1, C2, C11, C12, D1, D2, 31, and 34.
    example of how to disconnect the wires from the terminals at the top of the frame 8 AC precharge circuit breaker
  21. Remove the four M6 nuts that secure the insulator to the upper bus support panel in the adjacent power bay and move the insulator off of the panel studs so it is loose on the bus bars.
    example of how to remove the AC bus bar insulator from the frame 8 power bay
  22. Remove the 12 - 8 mm hex socket screws, washers, and bus bar plates that secure the circuit breaker bus bars to the bus bar extensions.
  23. IMPORTANT: The circuit breaker weights 11.0 kg (24.25 lb). It is recommended that two people complete these steps to remove the circuit breaker from the module. Brace the circuit breaker while the the mounting screws are removed.
  24. Remove the bottom two Phillips head screws that secure the circuit breaker to the chassis.
  25. Remove the top two Phillips head screws that secure the circuit breaker to the chassis and remove the circuit breaker from the chassis.
    example of how to remove the frame 8 AC precharge circuit breaker
  26. Install the AC precharge circuit breaker in the reverse order of removal.
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