ABB REM 543 Technical Reference Manual page 37

ABB Network Partner REM 543 Protection,
Monitoring and Control
Mathematically the operating condition can be expressed as:
U - (Rh + Rh + R
c (ext.) (int.)
• U = operating voltage over the supervised trip circuit
c
• I = measuring current through the trip circuit, approximately 1.5 mA (0.99 ... 1.72
c
mA)
• Rh = external shunt resistor value
(ext.)
• Rh = internal shunt resistor value, 1 kΩ
(int.)
• R = trip coil resistance value
s
The resistor Rh must be calculated so that the trip circuit supervision current
(ext.)
through the resistor is low enough not to influence the trip coil of the circuit breaker. On
the other hand, the voltage drop over the resistor Rh(ext.) must not be too high to jeop-
ardize the operating condition presented in the formula above.
The following values are recommended for the resistor Rh
Operating voltage Uc
48 V dc
60 V dc
110 V dc
220 V dc
-
Fig. 4.1.8.-1. Operating principle of the trip circuit supervision (TCS) function.
Technical Reference Manual
) x I > 20 V ac/dc, where
s c
Shunt resistor Rh(ext.)
Ω
1.2 k , 5 W
Ω
5.6 k , 5 W
Ω
22 k , 5 W
Ω
33 k , 5 W
+
Uc
Ic
20 V
Rh (int)
1 kΩ
Rh (ext)
Rs
Part 1, General
in figure below:
(ext.)
TCS_
CMTCS_
TCSSTATE ALARM
BS
TCSfunc
Page 37