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• Checking foundation bolts and nuts of valves & servomotor. Cleaning the bolts andnuts etc.• Checking servomotor piston and its collars & its gland packing• Checking hole of the servomotor cylinder• Checking the pins and bushes of servomotor & its air valve• Checking the diapharms in the opening & closing circuit. Checking the opening &closing times of the MIV.4.4.3 MAINTENANCE OF DRAFT TUBE GATESOne, two or three bulk head gates are needed to close off the draft tube. These areusually cable suspended gravity gates and designed for balanced pressure closure. These areusually dropped to close or lifted to open through hoisting arrangement having rope drums.The main problem with sealing is due to debris in bottom seal area. For withdrawal ofgate/ equalizing pressure across the gates is done with byepass line valve located with in gate.When machine are running these gates and hoist remains available for maintenance.These should always remain in perfect condition for use during emergencies of power station.During annual maintenance of the unit these gates are required to be lowered so thatdewatering of draft tube is possible. As such maintenance and overhaul of these gates aretaken up before starting annual maintenance of machine.Lubrication of operating mechanism, its electrical system and coating all ropes meantfor lifting are of main concern for maintenance.4.5 PROCEDURES FOR TYPICAL MAINTENANCE ACTIVITIESFig 1 to 4, 10, 12 to 14 have been taken from “Hydropower Stations: Generating Equipment and itsinstallation” by AN Goncharov4.5.1 Reassembly of Vertical Hydro UnitSequence and Checks• Lower all guide vanes.• Trial assembly of Turbine runner for checking clearance between runner & runnerchamber (Kaplan) or static labyrinths & rotating labyrinths (Francis).• After setting above clearances take out runner & shaft assy. to service by.• Assemble runner, runner shaft and top cover and lower the complete assembly in pit.Again check clearances between runner and runner chamber. Also check freemovement of guide vanes. Check top and bottom clearances of all guide vanes andset.• Lower all the guide apparatus components in the pit and carry out installation &setting.• Lower bottom bracket with brake, set elevation, centering and tighten withfoundation.• Lower rotor with brake track in pit.• Carry out fitting & setting of Thrust bearing (and other guide bearings).AHEC/MNRE/SHP Standards/ E&M Works – Guidelines for Operation and Maintenance of Small Hydropower Station 55
• Check rotor level, verticality of shaft and centering of shaft, correction of inclinationof shaft to be done at this stage itself (Alignment of generator).• Couple Exciter shaft and assemble exciters, PMG, Oil header (Kaplan) etc. carry outcentering and setting.• Couple Turbine and Generator shaft properly as per procedure with help of torquespanners. Ensure elongation of shaft bolts as per procedure.• Checking unit alignment and taking corrective action by providing shims orscrapping.• Carry out load sharing of thrust pads.• After completing assembly of machine and rotating the machine at no load checkbalancing of rotor as per procedure. Balancing of the machine by adding calculatedweight on rotor spider and at proper angle, is done.• Check vibrations of machine at no load, part load and full load, rectify defects if any.4.5.2 Checking Concentricity of Labyrinth SealsThe upper and lower labyrinth rings must be concentric with the shaft to within 10%of the gap on one side of the labyrinth seals. This is checked with a special device mountedon the shaft (Fig. 1)Fig 1: Device of checking concentricity of labyrinth-seal rings:1)Testing device; 2) support with roller; 3) indicators [Goncharov]4.5.3 Balancing of RunnerFor balancing of runner a balancing device, ‘1’, a steel plate ‘2’, a sphere ‘3’ will berequired (Fig. 2). The centre of gravity of runner must always be below centre of gravity ofsphere so that during balancing runner remains in stable position. Following steps are takento balance the runner.AHEC/MNRE/SHP Standards/ E&M Works – Guidelines for Operation and Maintenance of Small Hydropower Station 56
Page 1 and 2:
STANDARDS / MANUALS / GUIDELINES FO
Page 3 and 4:
ITEMSPAGE NO4.2 Preventive Maintena
Page 5 and 6:
SECTION - IGUIDELINES FOR OPERATION
Page 7 and 8:
2.1.2 Lake/Storage/PondThe operatio
Page 9 and 10: 2.2.3 Electrical• Air seal valve
Page 11 and 12: • Start command initiated(iv)Sync
Page 13 and 14: ‣ Check whether supply to various
Page 15 and 16: - Intake gates, bye pass gates, D.T
Page 17 and 18: • To arrange for evacuation of ma
Page 19 and 20: SECTION - IIGUIDELINES FOR MAINTENA
Page 21 and 22: 2.3 PREDICTIVE MAINTENANCEThis sort
Page 23 and 24: 6. Oil Leakage Unit:i) Check any le
Page 25 and 26: 5. Shaft Gland Seal and Air Seal:i)
Page 27 and 28: v) In case the runner is found to b
Page 29 and 30: iii) Preheating of the blade to abo
Page 31 and 32: E. GovernorDifferent types of gover
Page 33 and 34: Sl. No. Description Periodicity Rem
Page 41 and 42: 4.2.1 Daily ChecksSl.No.Assembly It
Page 43 and 44: 4.2.3 Annual Inspection & Maintenan
Page 45 and 46: Sl.No.Assembly Item Check Point Met
Page 47 and 48: • Check all joints, tightness of
Page 49 and 50: S.No.Item to beinspectedInspection
Page 57 and 58: 4.4 PREVANTIVE MAINTENANCE OF HYDRO
Page 59: Spherical valves (for heads more th
Page 63 and 64: • Any possible inbalance of runne
Page 65 and 66: The blades are set to the no-load p
Page 67 and 68: IV.Rotational Checks‣ Arrangement
Page 69 and 70: Fig 6: Resultant Method of Throw Ca
Page 71 and 72: Fig 9: checking Verticality of Gene
Page 73 and 74: oFig 11: Checking Balancing of Gene
Page 75 and 76: Procedure for preliminary alignment
Page 77 and 78: Fig 14: Determining Displacements o
Page 79 and 80: SECTION-IIIGENERAL GUIDE LINES1.0 G
Page 81 and 82: • On placing them on operation du
Page 83 and 84: Safety Precautions and Practices in
Page 85 and 86: Results of test and measurements ca
Page 87 and 88: (NAME OF POWER STATION)DAILY GENERA
Page 89 and 90: (NAME OF POWER STATION)DAILY TRIPPI
Page 91 and 92: UnitGENERATION(MU)TOTALTIME(Hrs:Min
Page 93 and 94: MONTHLY TRIPPING REPORTFOR THE MONT
Page 95 and 96: AHEC/MNRE/SHP Standards/ E&M Works
Page 97 and 98: (POWER STATION)ANNUAL MAINTENANCE S
Page 99 and 100: UNIT/ EQUIPMENT/ FEEDER BAY/:DATE &
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