GarrettCom Magnum 4K24F Installation And User Manual page 44

Magnum 4K24 Switches Installation and User Guide
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 &
125VDC dual source leads to the -48VDC, 24VDC and 125VDC power terminal block
on the Magnum 4K-Series Switch (shown in Figure )
The -48VDC terminal block on the Magnum 4K-Series Switch is located on
the right rear of the unit and is equipped
with five (5) screw-down lead posts (see
Fig 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.
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 4K unit has a floating ground, so the
user may elect to Ground either + or = terminal to suit the customer's use.
Before connecting to 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 chassis. Ensure that each lead is securely tightened.
The 24VDC & 125VDC terminal block on Magnum 4K-Series Switch also has
everything similar to –48VDC info. Described above.
C5.1 UL Requirements
The following must be adhered to in order to conform to UL requirements:
1. For power and earthing wiring, use minimum 22 AWG size wiring.
2. Fastening torque of the lugs on the terminal block: 9 inch pound max.
3. Equipment for use in a Restricted Access Location only.
4. Use only with listed 2A circuit breaker provided in the building installation.
5. Centralized DC Power Source cable securement, use at least four cable ties to
secure the cable to the rack at least 4 inches apart with the first one located
within 6 inches of the terminal block.
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A+ A- B- B+
36-70VDC
38
(10/04)
36-70VDC
GND