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T640 Three-Input 240-A DC Power Supply Description
Three-Input 240-A DC Power Supply
Each three-input 240-A DC power supply weighs approximately 25 lb (11.3 kg) and consists of three inputs, three 80-A circuit breakers, a fan, and LEDs to monitor the status of the power supply. Figure 1 shows the three-input 240-A DC power supply in 2-INPUT mode.
Figure 1: Three-Input 240-A DC Power Supply
Three-Input 240-A DC Power Supply Inputs
The three-input 240-A DC power supply inputs are labeled INPUT 0, INPUT 1, and INPUT 2, from top to bottom. Each input consists of –48 VDC and return, each with its own 80-A circuit breaker. The input mode switch on the faceplate allows you to set the DC power supply to either 2–INPUT or 3–INPUT mode. 2-INPUT mode is required for the T640 router and TX Matrix router.
Table 1 describes which components are powered by each input.
Table 1: Components Powered by Each Three-Input 240-A DC Power Supply Input
| Input | Three-Input Mode |
|---|---|
INPUT 0 | T640-SIBs, control boards, fan trays, Routing Engines, and FPCs in slots FPC0 and FPC1 |
INPUT 1 | FPCs in slots FPC2 through FPC7 |
INPUT 2 | This input is not supported in 2–INPUT mode. |
Three-Input 240-A DC Power Supply Load Sharing and Fault Tolerance
When the router is operating normally and both power supplies are switched on, load sharing between them occurs automatically. When one power supply fails or is turned off, the other power supply immediately assumes the entire electrical load for the system. A single power supply can provide full power for as long as the router is operational. Table 2 describes the behavior of the power supply if one of the inputs fails.
Table 2: Fault Tolerance
| Redundancy | Fault Tolerance When One Input Fails or is Disconnected |
|---|---|
Nonredundant power supply | If this input fails, the router shuts down. Note: We recommend that you install redundant power supplies. |
Redundant power supplies | If an input on one power supply fails, the other power supply assumes the electrical load for all inputs. If one input on the other power supply is not functional, the router shuts down. |
