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T640 Six-Input DC Power Supply Description


Power Supply Components

Each six-input DC power supply weighs approximately 39.7 lb (18.0 kg) and consists of six inputs, two blowers, a front and side air filter, and LEDs to monitor the status of the power supply. Each power supply is cooled by its own internal cooling system. Figure 1 shows the six-input DC power supply.


There are no circuit breakers or passive fuses in the router.

Figure 1: Six-Input DC Power Supply
Six-Input DC Power Supply


The six-input DC power supply inputs are labeled INPUT 0, INPUT 1, INPUT 2, INPUT 3, INPUT 4, and INPUT 5, from top to bottom. Each 60 A input consists of –48 VDC and return.

Table 1 describes which components are powered by each input.

Table 1: Components Powered by Each Six-Input DC Power Supply Input




Fan trays

INPUT 1 through INPUT 5

FPCs, Routing Engines, control boards, SIBs, craft interface, SCGs, and other components in the router.


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.