VAMP 259 - Page 244

7.4 Trip circuit supervision
7 Applications
Technical description
244
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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
2
aux
/P = 242 .