GarrettCom 6K16V - Manual (Page 60)

Magnum 6K16V Managed Fiber Switch Installation and User Guide (01/04)
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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 )
The -48VDC terminal block on the Magnum 6K16V 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.
Figure C5.0: -48VDC Dual-Source, wiring connections to the External
Terminal Block on a Magnum 48VDC with Dual-Source option
Note: The GND should be hooked up first. The 6K16V 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 “+ve potential”. The more “+ve” voltage
lead from 48V or –48V supply must be connected to the post labeled “+”.
The connection procedure is straightforward. Simply connect the DC leads to
the Switch’s power terminals, positive (+) and negative (-) screws. The use of Ground
(GND) is optional; it connects to the Switch chassis. Ensure that each lead is securely
tightened.
The 24VDC & 125VDC terminal block on Magnum 6K16V’s is similar to that
described in the –48VDC information above.
36-70VDC GND
A+ A- B- B+
36-70VDC