Table 5.1.4.13.-11
CBFAIL
Feature
Value
Set operate time
0.10...60.0 s
Phase-current threshold for external
triggering of the CBFAIL
*
pick-up/drop-off
0.13/0.11 x FLA
The accuracies apply only when the FLA secondary scaling factor has
been set to 1.
5.1.5.
Trip-circuit supervision
The trip-circuit supervision (TCS) detects open circuits, both when the circuit
breaker is open and closed, and trip-circuit supply failure.
The trip-circuit supervision includes:
*
Current limiter including the necessary hardware
*
Software-based function in the self-supervision system
The trip-circuit supervision is based on a constant current injection principle: by
applying an external voltage, a constant current is forced to flow through the
external trip circuit. If the resistance of the trip circuit exceeds a certain limit for
more than 21 seconds, due to oxidation or a bad contact, for instance, the trip-circuit
supervision is activated and a warning appears on the LCD together with a fault
code. The warning signal from the trip-circuit supervision can also be routed to SO2
by setting switch SGF1/8 to 1.
Under normal operating conditions, the applied external voltage is divided between
the relay
’
s internal circuit and the external trip circuit so that at least 20 V remains
over the relay
’
s internal circuit. If the external trip circuit
’
s resistance is too high or
the internal circuit
’
s too low, due to welded relay contacts, for instance, the voltage
over the relay
’
s internal circuit falls below 20 V (15...20 V), which activates the trip-
circuit supervision.
The operation condition is:
U
R
R
I
c
xt
s
inj
−
+
+
(
)
× ≥
R
e
int
20 V ac/dc
(3)
U
c
= operating voltage over the supervised trip circuit
I
inj
= current flowing through the trip circuit, ~1.5 mA
R
ext
= external shunt resistor
R
int
= internal shunt resistor, 1 k
Ω
R
s
= trip coil resistance
62
REM 610
REM 610
Motor Protection Relay
Technical Reference Manual - ANSI Version
1MRS755537
Summary of Contents for REM 610
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