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3-14 750/760 Feeder Management Relay GE Multilin

3.2 ELECTRICAL 3 INSTALLATION

3.2.7 LOGIC INPUTS

Ensure correct polarity on logic input connections and do not connect any logic input circuits to ground or

else relay hardware may be damaged.

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.

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 con-

tact is connected to the required logic input terminal. In addition, the negative side of the external source must be con-

nected to the relay’s DC negative rail at Terminal D12. The maximum external source voltage for this arrangement is

300 V DC.

Figure 3–17: DRY AND WET CONTACT CONNECTIONS

3.2.8 ANALOG INPUT

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 recom-

mended to minimize noise effects.

CAUTION

Dry Contact Connection

Wet Contact Connection

750/760 RELAY750/760 RELAY

C12

C1C1

C12

+32VDC

Logic Input 1

32VDC

DC Negative

DC Negative D12

D12

30 to 300 V DC

LOGICIN.CD

Courtesy of NationalSwitchgear.com

GE Feeder Management Relay 750 User Manual

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