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Power supplied to ABB system's power supply units and for external supply to I/O
can normally be obtained from the plant a.c. or d.c. supply sources.
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A power source can be rated as Installation Category II or III with respect to level of
disturbances, voltage variations and so on, according to IEC standards. Standard
voltage range is 110 - 240V a.c. Installation Category II denotes a higher quality
than III mains. The S800 I/O power supplies SD811 and SD812 are rated for
Overvoltage Category II for Installation Category III mains.
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When using a d.c. source, only floating battery or recitified d.c. systems can be used
for powering of ABB systems without galvanic isolation between the system and
the current source. With this type of supply, the power supply source is grounded in
the ABB equipment.
Externally grounded power supply requires an isolating d.c./d.c. converter for the
system.
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FCI/ModuleBus
Modem
SD811/SD812
WyhtrÃShtr
19.2 - 30
185 - 250
3BSE 020 923R101