The AC/DC sensitive residual current monitor RCMA420 is designed for monitoring earthed power supply systems (TN and TT systems) where smooth DC fault currents or residual currents continuously greater than zero may occur. These are in particular loads containing six-pulse rectifiers or one way rectifiers with smoothing, such as converters, battery chargers, construction site equipment with frequency-controlled drives. Currents in single conductors can be monitored too.
The prewarning stage (50…100 % of the set response value IΔn2) allow to distinguish between prewarning and alarm. Since the values are measured with measuring current transformers, the device is nearly independent of the load current and the nominal voltage of the system.
AC/DC sensitive residual current monitor Type B acc. to IEC 62020 and IEC/TR 60755
r.m.s. value measurement (AC+DC)
Two separately adjustable response values 10…500 mA
Frequency range 0…2000 Hz
Start-up delay, response delay and delay on release
Digital measured value display via LC display
Measured value memory for operating value
CT connection monitoring
LEDs: Power On, Alarm 1, Alarm 2