CHAPTER 2: INSTALLATION
ELECTRICAL INSTALLATION
345 TRANSFORMER PROTECTION SYSTEM – QUICKSTART GUIDE
33
Figure 2-21: Relay #1 Trip and Relay #2 Trip circuits with voltage monitoring
Contact inputs
External contacts can be connected to the relay’s ten (10) digital inputs. These contacts are
wet only.
The inputs can be programmed to different thresholds depending on the DC voltage (17,
33, 84, 166).
CAUTION:
Ensure correct polarity on contact input connections and do not connect any contact
input circuits to ground or else relay hardware may be damaged.
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 contact input terminal. In
addition, the negative side of the external source must be connected to the relay’s DC
negative rail at Terminal C11. The maximum external source voltage for this arrangement
is 300 V DC.
Figure 2-22: Wet contact connections
V
A2
B3
A3
Trip
Coil
DC +
DC -
Output Relay 1 (TRIP)
52a
contact
External
jumper
897786.cdr
V
B4
A4
B5
DC +
Output Relay 2 (TRIP)
52a
contact
External
jumper
Trip
Coil
DC -
Wet Contact Connection
345 RELAY
C1
Contact Input 1
Contact Input Common C11
V DC Power
Supply
LOGICIN.CDR
