Typical Wiring
745
Transformer Management Relay
Installat
ion
http://www.GEindustrial.com/multilin
3–10
GE Multilin
FIGURE 3–12: Zero-Sequence (Core Balance) CT Installation
AC Voltage Input
The 745 has one voltage divider type input for AC voltages. There are no internal
fuses or ground connections. Voltage transformers up to a maximum 5000:1 ratio
may be used. The nominal secondary voltage must be in the 60 to 120 V range.
Logic Inputs
External contacts can be connected to the 16 logic inputs. As shown, these contacts
can be either dry or wet. It is also possible to use a combination of both contact
types.
A dry contact has one side connected to Terminal D11. This is the +32 V DC voltage
rail. The other side is connected to the required logic input terminal. When a dry
contact closes, a 2.2 mA current flows through the associated circuit.
A wet contact has one side connected to the positive terminal of an external DC
power supply. The other side is connected to the required logic input terminal. In
addition, the negative side of the external source must be connected to the relay DC
NEGATIVE rail at terminal D12. The maximum external source voltage for this
arrangement is 300 V DC.
Correct polarity must be observed for all logic input connections or
equipment damage may result.
FIGURE 3–13: Dry and Wet Contact Connections
CAUTION
Dry Contact Connection
Wet Contact Connection
745 RELAY
745 RELAY
D11
D1
D1
D11
+32 V DC
+32 V DC
Logic Input 1
Logic Input 1
32 V DC
32 V DC
DC Negative
DC Negative
D12
D12
30 to 300 V DC
LOGICIN.CDR
Summary of Contents for Multilin 745
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