Dell Force10 S50N Series Installing Manual page 33

Figure 5-7. DC-DC Cable for S50V PSU
Follow the steps below to connect the S50V switch to the S50V external PSU.
Step Task
With the switch unplugged from AC power, connect the individual leads of the DC-to-DC cable to the DC
1
terminal lugs of the switch
Connect the gray wire to FG, red to RTN, brown to -48V. If you connect the blue lead of the Dell Force10 PSU to
Current Sharing, you put the PSU in load-sharing mode, which helps to enable more PoE ports. Alternatively,
leaving the wire unconnected puts the PSU in backup mode. The downside of selecting load-sharing mode is that,
if either the AC or DC fails, all PoE functionality is lost.
Figure 5-8. DC Terminals of the S50V Connected to the PSU Cable
CAUTION:
internal AC PSU, causing the AC PSU to continually attempt to boot up. The symptom is a clicking noise.
(Figure 5-8), with a #2 Phillips screwdriver.
Use only -48V DC. Using a higher voltage causes the DC source to take precedence over the
Installing Backup Power | 33