Bender RCM420-D-2 B74014002 Fiche De Données

Codes de produits
B74014002
Page de 4
24 
TDB401016en / 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
4.1
Residual current monitor
RCM420
Residual current monitor
for TN and TT systems 
(AC and pulsed DC currents)
RCM420
Product description
The AC and pulsed DC sensitive residual current monitor RCMA420-D (Type A) from Bender 
is designed for fault and residual current monitoring in earthed power supply systems (TN 
and TT systems) where an alarm is to be activated in the event of a fault, but disconnection 
must be prevented. In addition, the device can be used to monitor single conductors, 
such as PE conductors, N-PE connections and PE-PAS connections.
The prewarning stage (50…100 % of the set response value I
Δn2
) allow to distinguish bet-
ween prewarning and alarm. Since the values are measured with measuring current trans-
formers, the device is nearly independent of the load current and the nominal voltage of 
the system.
Applications
•  Residual current monitoring  in earthed two, three or four conductor systems
•  Current monitoring of single conductors de-energised under normal conditions
•   Socket-outlet circuits for devices which are operated unattended for a long time and 
which may not fail
•  Alarm systems, safety devices
•  Air conditioning systems, EDP systems
•  Cooling equipment with valuable frozen goods
• Canteen kitchens
•  Monitoring of earthed power supplies for stray currents
•  Impact on N conductors
•  Trace heating systems
Function 
Once the supply voltage U
S
 has been applied, the start-up delay "t" starts. Measured values 
exceeded during this time do not influence the switching state of the alarm relays.
Residual current monitoring takes place via an external measuring current transformer. 
The actual measured value is indicated on the LCD. In this way any changes, for example 
when circuits are connected to the system, can be recognised easily. 
If the measured value exceeds one or both response values, the response delays t
on1 / 2
 
begin. Once "t
on1 / 2
" have elapsed, the selected alarm relays switch). If the release value is 
not reached before the response delay "t
on
" has elapsed, the alarm LEDs "AL1 / AL2" do 
not light up and the alarm relays do not switch. The set release time "t
off
" begins when 
the measured value again falls below the release value (response value minus hysteresis) 
after the switching of the alarm relays. When "t
off
" has elapsed, the alarm relays switch 
back to their initial position. If the fault memory is enabled, the alarm relays remain in the 
alarm state 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. 
Connection monitoring
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. After eliminating the 
fault, the alarm relays return to their initial position either automatically or by pressing 
the reset button (fault memory behaviour).
Restart function
If an alarm is pending after resetting the alarm relay and restarting the system being monitored, 
this reset process is repeated until the preset number of restart cycles is completed.
As soon as the preset number of restart cycles is completed, the fault memory is set to ON.
Device features
•   AC and pulsed DC sensitive residual current 
monitor Type A according to IEC 62020
•   r.m.s. value measurement (AC)
•  Two separately adjustable response values
•  Frequency range 42…2000 Hz
•   Start-up delay, response delay and delay 
on release
• Restart function
•   Digital measured value display via LC display
•   Measured value memory for operating 
value
•  CT connection monitoring LED
•  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
•  Password protection for device setting
•  Device self monitoring
•  Sealable transparent cover
•  Two-module enclosure (36 mm)
•  
RoHS compliant 
•  
Push-wire terminal 
(two terminals per connection)
Approvals and certifications