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TX Matrix Three-Input 240-A 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

Three-Input 240-A DC Power Supply Inputs in 2-INPUT Mode

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 TX Matrix router.

Table 1 describes which components are powered by INPUT 0 and INPUT 1 in a three-input 240-A DC power supply in a TX Matrix router.

Table 1: TX Matrix Components Powered by Each Input

InputProvides Power to These Components


SIB in slots 0 and 1, Control Boards, Routing Engines, CIP, craft interface, and fan trays


SIBs in slot 2, 3, and 4


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

RedundancyFault 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.