Bender RCMA423AS, Руководство пользователя

Страница: 15 / 48

15 RCMA423AS_D00157_01_M_XXEN/08.2016
3. Function
3.1 Device features

AC/DC sensitive residual current monitor for mining according to
AS/NZS 2081:2011

Two separately adjustable response ranges (prewarning, alarm)

Adjustable switching hysteresis

r.m.s. value measurement

Start-up delay, response delay and delay on release

Measured value display via multi-functional LC display

Alarm indication via LEDs (AL1, AL2) and changeover contacts (K1, K2)

N/C operation or N/O operation selectable

Password protection against unauthorised parameter changing

Fault memory function can be switched off

CT connection monitoring
3.2 Function
Once the supply voltage U
s
is applied, the start-up delay is activated. Measu-
red values changing during this time do not influence the switching state of
the alarm relays. Residual current measurement takes place via external
W20AB…W210AB series measuring current transformers. The currently mea-
sured 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.
When the measured values exceed the 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 residual current falls below the release
value (response value minus hysteresis), the delay on release
t
off
begins. Once
t
off
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