Bender RCMA420-D-2 B74043002 データシート

40 

TDB404006en / Main catalogue part 4 – Residual current monitors, Residual current monitoring systems / 07.2010

Dipl.-Ing. W. Bender GmbH & Co. KG • Londorfer Str. 65 • 35305 Grünberg • Phone: 06401 807-0 • Fax: 06401 807-259

 

Subject to change ! – © Dipl.-Ing. W. Bender GmbH & Co. KG, Germany

•   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

•  Power On LED, LEDs: Alarm 1 / 2

•  Internal/external test/reset button

•   Two separate alarm relays 

(one changeover contact each)

•   N/O or N/C operation and fault memory 

behaviour selectable

•  Continuous self monitoring

•  Multi-functional LC display

•  Password protection for device settings

•  Sealable transparent cover

•  Two-module enclosure (36 mm)

•  

RoHS compliant

•  

Push-wire terminal
(two terminals per connection)

   

    

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 I

Δn2

) 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 monitoring in earthed two, three or four conductor systems 

(TN and TT systems)

•   Monitoring of variable-speed drives, UPS systems, construction site equipment, printing 

machines, battery systems, laboratory equipment, wood working machines, MF welding 
systems, furniture industry, medical electrical equipment, etc.

•   AC/DC sensitive current monitoring of single conductors de-energised under normal 

conditions (e.g. N and PE conductors)

Once the supply voltage U

S

 is applied, the start-up delay is activated. Measured values 

changing during this time do not influence the switching state of the alarm relays.

Residual current measurement takes place via an external measuring current transformer 
of the W20AB…W60AB series. The currently measured value is shown on the LC display. 
In this way any changes, for example when circuits are connected to the system, can be 
recognised easily. If the measured value exceeds the set response values, the response 
delays t

on1 / 2

 begin. Once the response delay t

on1 / 2

 has elapsed, the K1/K2 alarm relays 

switch and the alarm LEDs AL1/AL2 light up. If the current falls below the release value 
(response value plus hysteresis), the release delay t

off

. When toff has elapsed, the alarm 

relays return to their initial position and the alarm LEDs AL1/AL2 go out. If the fault memory 
is activated, the alarm relays remain in the alarm state and the LEDs light until the reset 
button is pressed or until the supply voltage is interrupted. The device function can be 
tested using the test button. Parameters are assigned to the device via the LCD and the 
control buttons on the front panel; this function can be password-protected.

The function of the device and the CT connections are continuously monitored. In the event 
of a fault, the alarm relays K1 / K2 switch without delay, the alarm LEDs AL1 / AL2 / ON flash. 
On removal of the fault, the alarm relays return to their initial position either automatically 
or by pressing the reset button.