standards / manuals / guidelines for small hydro development - AHEC

servo tube. The servo tube has ports to receive return oil to the pipes coming form OPUsump. This tube is guided by three sets of bushes in the oil tube. Due to run out of the shaftthese bushes has to press the servo tube. Failure of these had been very frequent in one of thepower station.Monitoring of wobbling of the servo tube with help of dial indicator may provide a guide lineand save the bushes from further wearing. Remedial measures to reduce run out of the servotube must be taken at this stage.At the time of assembly of various parts of header proper match marking and dowelling isessential so that reassembly may be correctly done.4.2 PREVENTIVE MAINTENANCE OF HYDRO GENERATORPreventive maintenance ensures a long trouble free operation of the generator. Given in thefollowing table are the recommended daily, monthly, once in 3 months, half yearly & yearlymaintenance checks to be conducted on the generator. While it is appreciated that it is not alwayspossible to rightly follow this schedule due to generator loading constraints, the recommendationgiven may be taken as a guide line and these may be altered slightly, based on the past experience.Sl. No. Description Periodicity Remarks1.00 Stator:1.01 Temperature record on log sheet for core and Hourlywinding, hot and cold air temperature1.02 Visual inspection of the overhang parts of the Once in 3stator winding.months1.03 Checking the fixing of winding, condition of Once in 3winding joints with bus bars etc.months1.04 Clean the winding with dry & clean Once in 3compressed air (2 to 3 kg/cm 2 ).months1.05 Check overhang parts of stator winding, busbars, inner periphery of stator core (ifpossible), parts of stator winding in slots(specially at sector joint) binding & spacersbetween the winding bars/ bandage rings.1.06 Check looseness of overhang, busbars slotwedges etc.1.07 Check the fixing of stator active iron with theframe body in all possible places. If it isnecessary, tighten the studs of pressingplates.1.08 Check pins & fixing of stator withYearlyYearlyYearlyYearlyCleaning to be donesuch that the dust doesnot collect in sidemachine.foundations.1.09 Check D.C. resistance, IR & PI value. Yearly Record to bemaintained1.10 Check functioning of RTDs of stator. Yearly -do-1.11 Blow the winding, active iron and bandagerings etc. with dry & clean compressed air (2YearlyAHEC/MNRE/SHP Standards/ E&M Works – Guidelines for Operation and Maintenance of Small Hydropower Station 27