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Magnum 6KQ Managed Field Switch Installation and User Guide (04/07)
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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 &
125VDC power terminal block on the Magnum 6Ks
Switch (shown in Figure to the right)
The -48VDC terminal block on the
Magnum 6KQ Switch is located on the left front of
the unit next to the Alarm terminal block and is
equipped with five (5) screw-down lead posts. The
primary terminals are identified as positive (A+),
Figure C5.0: DC Dual-Source, wiring connections to the External
Terminal Block on a Magnum -48VDC with Dual-Source option
negative (A-), and the secondary power terminals as negative (B-), positive(B+). The
chassis is “earth”. The Dual Source terminal block for the 24, 48 and 125VDC are same.
Note: The GND should be hooked up first. The 6KQ unit has a floating
ground, so the user may elect to Ground either + or = terminal to suit the
customer’s use. Before connecting hot lines to the Terminal Block of –
48VDC, 24VDC or 125VDC, always use a digital voltmeter to measure the
output voltage of the power supply and determine the lead which is more
GND
FUSE
+
-
SUPPLY
A+
A-
B-
B+
GND
CHASSIS
HUB
DC terminal
block