3com 7754 Manual De Usuario

To connect DC power cords, do the following:

1 Power off all the related parts of the switch when connecting the DC power cord. 

2 Loosen the mounting screw and remove the cover of the connection terminals on 

the DC power distribution box. 

3 Loosen the mounting nut of the connection terminal, using a socket wrench.

4 Connect the -48 V terminal (with a blue wire) of the DC power cord on the switch 

to the terminal marked with -48 V and fasten the nut. 

5 Connect the grounding terminal (with a black wire) of the DC power cord of the 

switch to the return terminal and fasten the mounting nut with socket wrench. 

6 Cover the connection terminals and fasten the mounting screws.

7 Connect the other end of the DC power cord to the connection terminal for 

power input to the switch. 

Figure 33   Connecting the DC Power Cord

1 -48 V input

2 Return

3 Grounding screw

4 Fastening screw

The dual AC input power module uses an internal switch that automatically selects 
the primary power source. However, to select the primary power source manually, 
do the following:

1 Connect the first power cord to the AC source or backup system that you select as 

the primary power source for the chassis. 

2 Power on the switch. The power module will receive power from the AC source 

you connected to. 

3 Connect the second power cord to the second AC source or backup system. 

If the primary AC source fails, the switch automatically fails over to the secondary 
AC source. There is no disruption to system operation during the power fail-over.

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