GarrettCom 6K32TRC C3.0 DUAL-SOURCE OPTION, THEORY OF OPERATION, C5.0 INSTALLATION, A+ A, B- B+

Magnum 6K32T & 6K32TRC Managed Switch Installation and User Guide 05/07)

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 )

The -48VDC terminal block on the Magnum 6K32T & 6K32TRC Switch, as shown in Fig C5.0 is located on the right rear of

the unit and is equipped with five (5)	A+ A-	B- B+
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		36-70VDC
(A-), and the secondary power	36-70VDC		GND

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. The6K32T & 6K32TRC 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

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