GarrettCom Magnum 6K32F Installation And User Manual page 74

Magnum 6K32F/FR/FC/FRC Managed Switch Installation and User Guide (05/08)
C3.0 DUAL-SOURCE OPTION, THEORY OF OPERATION
The Dual-Source DC power option is designed using diodes inside of the
chassis on each DC power input line. A diode is placed in each of the four input lines
(behind the four external power connection terminals) so that power from an external
source can only flow into the unit. This allows the unit to operate whenever DC power is
correctly applied to either or both of the two inputs
C4.0 FEATURES AND BENEFITS OF THE DUAL-SOURCE DESIGN
a) The Switch unit can receive power from either input, "A" or "B". The hub will
normally draw its power from the DC source with the highest voltage at a given time.
b) The Switch unit will not allow power to flow from a higher voltage input to a lower
voltage input, i.e. the two DC power sources are not mixed together by the hub.
c) When one correct DC input is present, the Switch will receive power if the other DC
input is absent, or even if it is connected with reverse polarity or shorted or grounded.
d) Reverse polarity connections, if they should accidentally occur on either input, will
not damage the Switch or power supply internally (nor will it blow the fuse in the
internal power supply) because of the blocking action of the diodes. This is true even
if one input connection is reversed while the Switch is operating from the other
source.
e) The Switch will not receive power (and will not work) when both inputs are
simultaneously absent or are both incorrectly connected.
C5.0 INSTALLATION
This section describes the proper connection of the -48VDC, 24VDC and
125VDC dual source leads to the -48VDC, 24VDC 7 125VDC power terminal block on
the Magnum 6Ks Switch
(shown in Figure )
The -48VDC terminal block on the
Magnum 6K32F Series Switch, as
shown in Fig C5.0 is located on the
right rear of the unit and is equipped
with five (5) screw-down lead posts. If it is the reverse model it is located on the left
rear. The primary terminals are identified as positive (A+), negative (A-), and the
secondary power terminals as negative (B-), positive(B+). The chassis "earth" or ground
(GND) is a threaded post with a #6 nut. The Dual Source terminal block for the 24VDC
and 125VDC are similar.
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