ABB Industrial IT enabled REX 521 - Single-pole power outputs (PO); Signalling outputs (SO)

20
1MRS 751108-MUM
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Technical Reference Manual, General
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doubpolerex
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The single-pole power outputs PO1...3 are outputs where the object to be controlled
is connected in series with two heavy-duty output relay contacts, see the Figure
4.1.8.2.-1 below. These outputs can be used for tripping purposes and for circuit
breaker and disconnector control. Two singe-pole outputs may be used to obtain
another double-pole output.
PO1connrex
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The signalling relay outputs (SO1 and SO2) are not heavy-duty outputs and thus
they cannot be used for controlling, for example, a circuit breaker. Available relay
contacts are Normally Open/Normally Closed type (NO/NC), see the Figure
4.1.8.3.-1 below. These outputs can be used for alarming and other signalling
purposes.
NoncRex
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+
-
CB
HSPO1
+
-
CB
PO1...3
NO/NC
e.g.
SO1