7.4 Trip circuit supervision
7 Applications
Technical description
244
VAMP 24h support phone +358 (0)20 753 3264
VM259.EN007
Figure 7.4.2-6 An example of digital input DI1 configuration for trip circuit
supervision with one wet digital input.
Figure 7.4.2-7 An example of output matrix configuration for trip circuit
supervision with one wet digital input.
Example of dimensioning the external resistor R:
U
aux
= 110 Vdc –5 % + 10%
Auxiliary voltage with tolerance. Short time voltage
dips more than 5 % are not critical from the trip
circuit supervision point of view.
Relay type for the K1 auxiliary relay:
Phoenix Contact 2941455
EMG 17-REL/KSR-120/21-21-LC Au
U
K1
= 120 Vac/dc –20 % + 10%
Coil voltage of the auxiliary relay K1
I
K1
= 6 mA
Nominal coil current of the auxiliary relay K1
P
CBcoil
= 50 W
Rated power of the open coil of the circuit breaker.
U
min
= U
aux
– 5 % = 104.5 V
U
max
= U
aux
+ 10 % = 121 V
U
K1min
= U
K1
– 10 % = 96 V
R
K1coil
= U
K1
/I
K1
= 20 k
.
I
K1min
= U
K1min
/R
K1coil
= 4.8 mA
I
K1max
= U
K1max
/R
K1coil
= 6.1 mA
R
CBcoil
= U
2aux
/P = 242
.