GE Multilin 745 Instruction Manual

Typical Wiring 745Transformer Management RelayInstallationhttp://www.GEindustrial.com/multilin 3ñ11GE MultilinControl Power The label found on the left side of the relay specifies its order code or modelnumber. The installed power supply operating range will be one of the following.LO: 25 to 60 V DC or 20 to 48 V ACHI: 88 to 300 V DC or 70 to 265 V ACEnsure the applied control voltage matches the requirements of the relayísswitching power supply. For example, the HI power supply will work with any DCvoltage from 88 to 300 V, or any AC voltage from 70 to 265 V. The internal fuse mayblow if the applied voltage exceeds this range.Control power supplied to the relay must match the installed power supplyrange. If the applied voltage does not match, damage to the unit mayoccur.FIGURE 3ñ14: Control Power ConnectionAnalog Input Terminals A1 (+) and A2 (ñ) are provided for the input of a current signal, from oneof the following: 0 to 1 mA, 0 to 5 mA, 0 to 20 mA, or 4 to 20 mA transduceroutputs. This current signal can represent any external quantity, such astemperature, current or voltage. Be sure to observe polarity markings for correctoperation. Both terminals are clamped to within 36 volts of ground with surgeprotection. As such, common mode voltages should not exceed this limit. Shieldedwire, with only one end of the shield grounded, is recommended to minimize noiseeffects. The A2 (ñ) terminal must be connected to the A5 (Analog Output Common)terminal at the 745.Tap Position Input Terminals A3 (+) and A4 (ñ) are provided to monitor the position of an Onload TapChanger from a stepped-resistance position indicator device. Terminal A3 isconnected internally to a 4.3 mA current source. This current is used to measure thevalue of the external resistance. The 745 uses the measured resistance value tocalculate the Tap Position. See Dynamic CT Ratio Mismatch Correction on page 5ñ5for more details on the tap position input.The maximum total resistance the Tap Changer input can measure is 5.1 KΩ. Forexample, the maximum resistance increment per tap for a 33-position Tap Changershould not exceed 151 Ω.RTD Driver/Sensor Terminals B10 (RTD Hot), B11 (RTD Comp) and B12 (RTD Ret) provide for theconnection of various types of RTD devices. This connection may be made using twoor three wires to the RTD. Terminal B10 is connected internally to a 5 mA currentsource for energizing the RTD. Terminal B11 is connected internally to a 5 mAWARNING