GE Multilin 745

Typical Wiring
745
Transformer Management Relay
Installation
http://www.GEindustrial.com/multilin
3–11
GE Multilin
Control Power The label found on the left side of the relay specifies its order code or model
number. The installed power supply operating range will be one of the following.
LO: 25 to 60 V DC or 20 to 48 V AC
HI: 88 to 300 V DC or 70 to 265 V AC
Ensure the applied control voltage matches the requirements of the relay’s
switching power supply. For example, the HI power supply will work with any DC
voltage from 88 to 300 V, or any AC voltage from 70 to 265 V. The internal fuse may
blow if the applied voltage exceeds this range.
Control power supplied to the relay must match the installed power supply
range. If the applied voltage does not match, damage to the unit may
occur.
FIGURE 3–14: Control Power Connection
Analog Input Terminals A1 (+) and A2 (–) are provided for the input of a current signal, from one
of the following: 0 to 1 mA, 0 to 5 mA, 0 to 20 mA, or 4 to 20 mA transducer
outputs. This current signal can represent any external quantity, such as
temperature, current or voltage. Be sure to observe polarity markings for correct
operation. Both terminals are clamped to within 36 volts 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. The A2 (–) terminal must be connected to the A5 (Analog Output Common)
terminal at the 745.
Tap Position Input Terminals A3 (+) and A4 (–) are provided to monitor the position of an Onload Tap
Changer from a stepped-resistance position indicator device. Terminal A3 is
connected internally to a 4.3 mA current source. This current is used to measure the
value of the external resistance. The 745 uses the measured resistance value to
calculate the Tap Position. See Dynamic CT Ratio Mismatch Correction on page 5–5
for more details on the tap position input.
The maximum total resistance the Tap Changer input can measure is 5.1 KΩ. For
example, the maximum resistance increment per tap for a 33-position Tap Changer
should not exceed 151 Ω.
RTD Driver/Sensor Terminals B10 (RTD Hot), B11 (RTD Comp) and B12 (RTD Ret) provide for the
connection of various types of RTD devices. This connection may be made using two
or three wires to the RTD. Terminal B10 is connected internally to a 5 mA current
source for energizing the RTD. Terminal B11 is connected internally to a 5 mA
WARNING