Eaton Digitrip 520 - Page 13

13
Instructional Leaflet IL70C1037H05
Effective October 2009
Digitrip models 520, 520i; and 520M, 520Mi,
520MC, 520MCi trip units for use only in
Magnum and Magnum DS circuit breakers
EATON CORPORATION www.eaton.com
Figure 7. Three-Pole, Four-Wire Breaker with Neutral Sensor Connections for 3200A Frame Using Residual Ground Fault Sensing
Figure 8. Neutral Sensor Connections for 4000A Frame Using Residual Ground Fault Sensing
L
N
R
5
R/1
R/1
K2-8
B-4
B-6
K1-4
K1-3
10:1
10:1 Aux. CT
K2-9
K2-1
K2-7
B-5
B-7
K1-5
K1-2
+
-
L
B
L
C
L
A
K1-6
K1-7
K1-8
K1-9
1
1
1
Source
Trip
Actuator
Black
Digitrip 520
with GF
a
b
c
Load
a
In this scheme, all breaker secondary currents (at the 100 mA level) are summed together at the PC board donut transformer to sense
ground fault via element R
5
.
b
No jumper on secondary contacts B-6, B-7.
c
Neutral input (if four-wire) is via contacts B-4, B-5. Neutral current input to secondary contacts is 1A, equivalent to one per unit ground.
K2-8
K2-9
B-4
B-6
20:1 Aux. CTs
20:1
K1-3
K2-7
B-5
B-7
K1-2
+
-
L
A2
L
B1
L
B2
L
C1
L
A1
L
N1
L
N2
L
C2
K1-4
K2-1
K1-5
K1-6
K1-7
K1-8
K1-9
2000:1
2000:1
2000:1
2000:1
2000:1
2000:1
2000:1
2000:1
R
5
Source
Trip
Actuator
Black
Digitrip 520
with GF
a
b
Load
a
In this scheme, all breaker secondary currents (at the 100 mA level) are summed together at the PC board donut transformer to sense ground
fault via element R
5
.
b
In this scheme, the current sensors in the breaker poles are parallel-wired to achieve a 4000A breaker rating. Other available ratings in this
double-wide configuration are 6300A, 5000A, 3200A, 2500A, and 2000A.