Eaton Cutler-Hammer Digitrip 520M - Page 11

Effective 8/13/99
Page 11I.L. 70C1037H02
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
.
No jumper on secondary contacts B-6, B-7.
Neutral input (if 4-wire) is via contacts B-4, B-5. Neutral current input to secondary contacts is 1A,
equivalent to 1 per unit ground.
Source
L
N
R
5
Digitrip 520
with GF
R/1
R/1
3
3
2
2
1
1
K2-8
B-4
Load
Notes:
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
Black
Trip
Actuator
+
-
L
B
L
C
L
A
K1-6
K1-7
K1-8
K1-9
1
1
1
Figure 2.2 3-Pole, 4-Wire Breaker with Neutral Sensor Connections for 3200A Frame Using Residual GF Sensing
Source
Load
K2-8
K2-9
B-4
B-6
20:1 AUX. CTs
20:1
K1-3
K2-7
B-5
B-7
K1-2
Black
Trip
Actuator
+
-
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
1
2
R
5
Digitrip 520
with GF
1
2
Notes:
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 .
In this scheme, the current sensors in the breaker poles are parallel-wired to achieve a 4000 amp
breaker rating. Other available ratings in this double-wide configuration are 6300A, 5000A,
3200A, 2500A, and 2000A.
R
5
Figure 2.3 Neutral Sensor Connections for 4000A Frame Using Residual Ground Fault Sensing
Courtesy of NationalSwitchgear.com