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Magnum 6K25e Gigabit Fiber Switch Installation and User Guide (10/07)
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With the exception of the dual DC input power connections and the power
supply, all specifications and configuration options for the Magnum 6K25e -48VDC,
24VDC and 125VDC models with this Dual-Source option are identical to those listed in
the Magnum 6K25e Fiber Switches Installation and User Guide, including Appendix B
“Internal DC Power Supply Option”
C2.0 MAGNUM 6K25E, with -48VDC, 24VDC and 125VDC Dual-Source option
The 6K25e-Switch models with the internal -48VDC, 24VDC and 125VDC
Dual-Source power supply are designed for installations where a battery plant is the
power source, and where two separate power sources are utilized in order to increase
operational uptime and to simplify maintenance.
The functionality of the Magnum 6K25e Switch -48VDC, 24VDC and
125VDC Dual-Source Option units is identical to the standard AC-powered models.
Refer to the main sections of this Installation and User Guide for a detailed description
of the Magnum 6K25e Switches.
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 )
GND
FUSE
+
-
SUPPLY
A+
A-
B-
B+
GND
CHASSIS
HUB