VALVE 6W7451 - Caterpillar

Illustration 1 g01269094
Bypass Static Switch Assembly (1) "K4" Contactor (2) Line Disconnect or Fuse Disconnect (3) Fuses "F22, F23, F24" (4) Snubber Assemblies (5) Thyristor (6) Bypass Cabinet Controller (7) Line Disconnect or Thyristor DisconnectDescription
The optional Bypass Static Switch Assembly is located behind the door in the middle of the cabinet and connected to the right panel.Fuses
Refer to Systems Operation, Testing and Adjusting, RENR9988, "System Fuses (SMS Bypass Cabinet)" for information of the fuse, installation, and removal procedures.Contactor for the Bypass Static Switch "K4"
The contactor for the Static Bypass "K4" is located on the rear of the Static Bypass panel.Board for the Bypass Cabinet Controller (BCC)
The BCC (6) is located on the front of the Static Bypass assembly. The BCC (6) acts as an interface between the UPS and the Static Bypass. The BCC (6) is the controller for the Static Bypass option in Single Module System (SMS). The BCC (6) receives logic signals. The BCC (6) drives the gate signals of the bypass static switch.Removal Procedure for the Board
Refer to Systems Operation, Testing and Adjusting, RENR9988, "Internal Component Preremoval Steps (SMS Bypass Cabinet)" in order to shut down the system and gain access to internal components.
Illustration 2 g01269152
Board for the Bypass Cabinet Controller
Disconnect all connectors. Verify the labeling of the wires for subsequent installation. Refer to Illustration 2.
Disconnect the four screws that connect the board to the standoffs on the right panel.Installation Procedure for the Board
Position the board in the cabinet over the white standoffs that are connected to the right panel.
Attach the board to the standoffs with four screws.
Connect the wire connectors into the correct connectors on the board. Check the labels on each connector for proper placement.Thyristors
Three thyristors (5) are located on the static bypass for each of the following phases: A, B and C.The thyristors (5) act as a static switch. Also, the thyristors (5) allow a rapid changeover when you change between the bypass and on-line states.Snubber Assemblies
"Snubber assemblies" (4) are connected between the input and the output on each of the three static bypass thyristors (5) .The snubber assemblies (4) prevent false turn-ons of the thyristor that are caused by voltage transients.Removal Procedure for the Assembly
All parts of the Static Bypass Assembly are removed as a unit and installed as a unit.
Refer to Systems Operation, Testing and Adjusting, RENR9988, "Internal Component Preremoval Steps (SMS Bypass Cabinet)" in order to shut down the system and gain access to internal components.
Unplug the line disconnect or fuse disconnect (2) at the top of the assembly.
Unplug the line disconnect or the thyristor disconnect (3)