Analog Input - GE 750 Instruction Manual

CHAPTER 3: INSTALLATION
3.2.9 Logic Inputs
Note
NOTE

3.2.10 Analog Input

3.2.11 Analog
Outputs
Note
NOTE
750 FEEDER MANAGEMENT RELAY – INSTRUCTION MANUAL
External contacts can be connected to the relay's fourteen (14) logic inputs. As shown,
these contacts can be either dry or wet. It is also possible to use a combination of both
contact types.
Ensure correct polarity on logic input connections and do not connect any logic input
circuits to ground or else relay hardware may be damaged.
A dry contact has one side connected to Terminal C12. This is the +32 V DC voltage rail. The
other side of the dry contact is connected to the required logic input terminal. When a dry
contact closes, a current of approximately 2 mA will flow through the associated circuit.
A wet contact has one side connected to the positive terminal of an external DC power
supply. The other side of this contact is connected to the required logic input terminal. In
addition, the negative side of the external source must be connected to the relay's DC
negative rail at Terminal D12. The maximum external source voltage for this arrangement
is 300 V DC.
Dry Contact Connection
750/760 RELAY
+32 V DC
Logic Input 1
32 V DC
DC Negative
FIGURE 3–16: Dry and Wet Contact Connections
It is recommended to use shielded twisted pair wires grounded at one end only for analog
input and analog output connections to the relay. Ensure the maximum burden limits are
not exceeded as per relay specifications and avoid locating wire in close proximity to
current carrying cables, contactors or other sources of high EMI.
Terminals A1 (+) and A2 (–) are provided for the input of a current signal from a wide variety
of transducer outputs - refer to technical specifications for complete listing. This current
signal can represent any external quantity, such as transformer winding temperature, bus
voltage, battery voltage, station service voltage, or transformer tap position. Be sure to
observe polarity markings for correct operation. Both terminals are clamped to within 36 V
of ground with surge protection. As such, common mode voltages should not exceed this
limit. Shielded wire, with only one end of the shield grounded, is recommended to minimize
noise effects.
It is recommended to use shielded twisted pair wires grounded at one end only for analog
input and analog output connections to the relay. Ensure the maximum burden limits are
not exceeded as per relay specifications, and avoid locating wire in close proximity to
current carrying cables, contactors or other sources of high EMI.
Wet Contact Connection
750/760 RELAY
C12
+32 V DC
C1 Logic Input 1
32 V DC
DC Negative
D12
ELECTRICAL INSTALLATION
C12
C1
30 to 300 V DC
D12
LOGICIN.CDR
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