GE 469 Instruction Manual page 25

2 INSTALLATION
The zero-sequence connection is recommended. Unequal saturation of CTs, size and location of motor,
resistance of power system and motor core saturation density, etc., may cause false readings in the resid-
NOTE
ually connected GF circuit.
Only one ground input should be wired – the other input should be unconnected.
NOTE
The exact placement of a zero-sequence CT to detect only ground fault current is shown below. If the core balance CT is
placed over shielded cable, capacitive coupling of phase current into the cable shield during motor starts may be detected
as ground current unless the shield wire is also passed through the CT window. Twisted pair cabling on the zero-sequence
CT is recommended.
SHIELDED CABLE
GE Multilin
Courtesy of NationalSwitchgear.com
Figure 2–13: CORE BALANCE GROUND CT INSTALLATION
469 Motor Management Relay
2.2 ELECTRICAL
UNSHIELDED CABLE
2
2-11