Magnum Quad-Series Fiber Switches
Installation and User Guide (06/09)
48
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All Port Module options are available for configuration with Dual-Source Option units.
Refer to the main sections of this
Installation and User Guide
for a detailed description
of the Magnum Quad-Series Switches.
C3.0 DUAL-SOURCE
OPTION, THEORY OF OPERATION
The Dual-Source DC power option is designed using diodes inside of the
switch 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 switch. This allows the switch
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 can receive power from either input, “A” or “B”. The switch will normally draw its
power from the DC source with the highest voltage at a given time.
b)
The switc
h
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 switch.
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, 24, 100 and
125VDC dual source leads to the DC power terminal block on the Magnum Quad-Series
Switch (shown in Figure C4.0 with 48v input as example).
The –48VDC terminal block on the Magnum Quad-Series Switch is located on
the right rear of the unit and is equipped with five (5) screw-down lead posts (see Figure
C5.0). 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 24, 100
and 125VDC are similar.
Figure C5.0: DC Dual Source, wiring connection to the external Terminal Block
on a Magnum QS5116 48VDC wih Dual-Source option
GND
FUSE
+
-
SUPPLY
A+
A-
B-
B+
GND
CHASSIS
HUB
36-70VDC
GND
A+ A- B- B+
36-70VDC
