VAMP 59 - Page 171

Technical description
7 Application
7.2 Trip circuit supervision
VM59.EN001
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171
Figure 7.2.1-3 An example of digital input DI1 configuration for trip circuit
supervision with one digital input.
Figure 7.2.1-4 An example of output matrix configuration for trip circuit
supervision with one digital input.
Example of dimensioning the external resistor R:
U
AUX
=
110 Vdc –20 % + 10%
Auxiliary voltage with tolerance
U
DI
=
18 Vdc
Threshold voltage of the digital input
I
DI
=
3 mA
Typical current needed to activate the digital input
including a 1 mA safety margin.
P
COIL
=
50 W
Rated power of the open coil of the circuit breaker. If
this value is not known, 0  can be used for the R
COIL
.
U
MIN
=
U
AUX
– 20 % = 88 V
U
MAX
=
U
AUX
+ 10 % = 121 V
R
COIL
=
U
2
AUX
/P = 242 .