GE MiCOM P40 Agile Technical Manual

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Contents

P44x/EN MT/Hb6 Maintenance(MT) 10-16 MiCOM P40 Agile P442, P444Figure 10: Typical opto board1.4 RecalibrationRecalibration is not usually required when a PCB is replaced unless it happens to be one ofthe two boards in the input module, the replacement of which directly affect the calibration.Although it is possible to carry out an on-site recalibration, this requires test equipment withsuitable accuracy and a special calibration program to run on a PC. It is thereforerecommended that the work be carried out by the manufacturer, or entrusted to an approvedservice centre.1.5 Changing the batteryEach relay has a battery to maintain status data and the correct time when the auxiliarysupply voltage fails. The data maintained includes event, fault and disturbance records andthe thermal state at the time of failure.This battery will periodically need changing, although an alarm will be given as part of therelay’s continuous self-monitoring in the event of a low battery condition.If the battery-backed facilities are not required to be maintained during an interruption of theauxiliary supply, the steps below can be followed to remove the battery, but do not replacewith a new battery.1.5.1 Instructions for Replacing The BatteryOpen the bottom access cover on the front of the relay.Gently extract the battery from its socket. If necessary, use a small screwdriver to prise thebattery free.Ensure that the metal terminals in the battery socket are free from corrosion, grease anddust.The replacement battery should be removed from its packaging and placed into the batteryholder, taking care to ensure that the polarity markings on the battery agree with thoseadjacent to the socket.Note: Only use a type ½AA Lithium battery with a nominal voltage of 3.6 V.