Siemens SIPROTEC 4 7VK61 - Page 181

To keep the circuit breaker trip coil not energized in the above case,R
min
is derived as:
[formel-rmin-260602-kn, 1, en_GB]
Ι
BI (HIGH)
Constant current with activated BI ( = 1.8 mA)
U
BI min
Minimum control voltage for BI
19 V for delivery setting for nominal voltages of 24 V/48 V/60 V;
88 V for delivery setting for nominal voltages of 110 V/125 V/220 V/250 V;
176 Vfor delivery setting for nominal voltages of 220 V/250 V
U
CTR
Control voltage for trip circuit
R
CBTC
DC resistance of circuit breaker trip coil
U
CBTC (LOW)
Maximum voltage on the circuit breaker trip coil that does not lead to tripping
If the calculation results that R
max
< R
min
then the calculation must be repeated, with the next lowest switching
threshold U
BE min
and this threshold must be implemented in the relay using plug-in jumpers (see Section
“Hardware Modifications”).
For the power consumption of the resistance the following applies:
[formel-leistungvon-r-260602-kn, 1, en_GB]
Example:
Ι
BI (HIGH)
1.8 mA (vom SIPROTEC 4 7VK61)
U
BE min
19 V for delivery setting for nominal voltages 24 V/48 V/60 V
(from the device 7VK61);
88 V for delivery setting for nominal voltages 110 V/125 V/220 V/250 V
(from the device 7VK61);
176 V for delivery setting for nominal voltages 220 V/250 V
(from the devicet 7VK61)
U
ST
110 V (system / trip circuit)
R
CBTC
500 Ω (system / trip circuit)
U
LSS (LOW)
2 V (system / trip circuit)
[beispiel-rmax-150502-kn, 1, en_GB]
[beispiel-rmin-150502-kn, 1, en_GB]
[beispiel-rmittelwert-150502-kn, 1, en_GB]
The closest standard value of 39 kΩ is selected; the power is:
Mounting and Commissioning
3.1 Mounting and Connections
SIPROTEC 4, 7VK61, Manual 181
C53000-G1176-C159-5, Edition 05.2018