GarrettCom 6K8 manual C3.0 DUAL-SOURCE OPTION, Theory of Operation

Magnum 6K8-Series Industrial Field Switch Installation and User Guide 03/06)

Power Supply (Internal, 125VDC Dual-Source, model # Dual-Src-125V)

DC Power Connector: First Source: “A+”, “A-“, 2nd Source “B-“, “B+”

GND: Terminal for “earth” or ground wire connection to the hub chassis

Input: Two separate sources, each at 88 - 300 VDC

With the exception of the dual DC input power connections and the power supply, all specifications and configuration options for the Magnum 6K8-Series -48VDC, 24VDC and 125VDC models with this Dual-Source option are identical to those listed in

the Magnum 6K8-Series Fiber Switches Installation and User Guide, including Appendix

B “Internal DC Power Supply Option”

C2.0 MAGNUM 6K8-SERIES, with -48VDC, 24VDC and 125VDC Dual-Source option (OPTIONAL)

The 6K8-Series-Switch models with the internal -48VDC, 24VDC and 125VDC Dual-Source power supply are designed for installations where a battery plant is the power source, and where two separate power sources are utilized in order to increase operational uptime and to simplify maintenance.

The functionality of the Magnum 6K8-Series Switch -48VDC, 24VDC and 125VDC Dual-Source Option units is identical to the standard AC-powered models. Refer to the main sections of this Installation and User Guide for a detailed description of the Magnum 6K8-Series Switches.

C3.0 DUAL-SOURCE OPTION, THEORY OF OPERATION

The Dual-Source DC power	A+	HUB
option is designed using diodes inside
	A-	SUPPLY
of the chassis on each DC power input		+
	B-	- FUSE
line. A diode is placed in each of the
	B+
four input lines (behind the four
	GND	CHASSIS
external power connection terminals)
		GND

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)

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