Specifications

Cable, CompactFlash and Accessory Specifications
A-22
XSR-1850 Redundant Power System
The optional XSR-1850 Redundant Power System, as shown in Figure A-27, is an external,
supplemental power source. This 50-watt, AC to DC power supply is a redundant unit which is
operated in parallel with the standard internal power supply, with which it shares power buses.
The power system requires no configuration - it begins operating when all cables are connected.
The power system utilizes a droop sharing scheme such that at greater than 50% of a full load,
plus or minus 10%, each supply delivers 50% of the required load for 5.1 volt output. Passive
current sharing proveds 50%, plus or minus 30%, of the system load required for +12 and -12 volt
outputs. It also features over-voltage, over-current, and short-circuit protection including a 250
volt minimum fuse.
Figure A-27 XSR-1850 Redundant Power System
Up to four power supplies can be installed in the 1U Passive Power Chassis, as shown in
Figure A-28, which can be rack mounted. Two-foot long DC power harnesses are provided to
attach XSRs and the power chassis, as well as a standard, 2-meter shielded power cord for the
chassis-to-wall outlet connection. Power supplies are hot swappable and are equipped with a
built-in fan which extends the unit’s lifespan but are not essential for normal functionality.
Figure A-28 Passive Power Chassis (Fully Loaded)
Refer to Figure A-29 for chassis DC output pinout assignments.