Safety instructions
14
RCMS460-490_D00067_03_M_XXEN/12.2017
2.3 Intended use
The RCMS460 or RCMS490 residual current monitor is designed for measuring
residual and operating currents TT and TN-S systems (measuring range see
"Chapter 8.3 Technical data", paragraph "measuring circuit"). Alternatively, di-
gital inputs can be scanned and evaluated.
The RCMS system consists of one or more RCMS460-D/-L or RCMS490-D/-L re-
sidual current monitors, which are able to detect and evaluate fault, residual
and operating currents in earthed power supplies via the related measuring
current transformers. The maximum voltage of the system to be monitored
depends on the nominal insulation voltage of the measuring current transfor-
mer used in the case of busbar systems, resp. depend on the cables or conduc-
tors that are routed through.
To measure AC/DC sensitive residual currents (according to IEC/TR 60755:
Type B) closed W…AB series measuring current transformers are required.
Six W…AB series measuring current transformers require one AN420 or
AN110 power supply unit.
For alternating and pulsating currents (according to IEC/TR 60755: Type A
W… (closed), WR… (rectangular), WS… (split-core) and WF… (flexible) series
measuring current transformers are used.
Any combination of the various measuring current transformer series can be
connected to the evaluator measuring channels.
Each RCMS460-D/-L and RCMS490-D/-L has 12 measuring channels. Up to 90
residual current monitors can be connected via a BMS bus (RS-485 interface
with BMS protocol), thereby up to 1080 measuring channels (sub-circuits) can
be monitored.
If this product is used for personnel protection, fire or plant protection, the fre-
quency response can be set accordingly. The measured currents can be analysed
for harmonics. The THF can be determined too (THF =
T
otal
H
armonic
F
actor).
The product must be adapted to local equipment and operating conditions
by making individual parameter settings, in order to meet the requirements
of applicable standards and to attain the protection goals.
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