turbine4

4LECTURE

AUXILIARY OIL PUMP, TURNING OIL PUMP, TURNING GEAR MAINTENANCE &

GOVERNOR PEDESTAL ASSEMBLY

SUB - OBJECTIVE

At the end of the lesson the Trainee will be able to demonstrate an understanding of Auxiliary oil pump, turning oil pump, turning gear maintenance & Governor pedestal assembly.

1.0 MOTOR DRIVEN AUXILIARY OIL PUMP

Fig. 14-4-1 shows the motor driven, vertical shaft, centrifugal type auxiliary oil pump which is used to supply oil to the system during the starting and stopping periods when the pressure delivered by the main pump is too low for the turbine requirements: it will start automatically when the pressure in the system drops below the predetermined point.

The unit, as shown in Fig. 14-4-16, is designed for mounting on the oil reservoir so that the pump impeller is always below the minimum oil level. This arrangement insures a positive suction head, and eliminates the necessity of priming the pump.

The pump impeller 23 is keyed on the lower end of the shaft 13 and further secured by the nut 30. Leakage from the discharge side back to the suction is limited to a minimum by the small clearance between the seal rings 22 and 25 on the pump body and the seal rings 24 and 37 on the impeller hubs. The sheet metal screen 27 is used to protect the impeller against debris.

The entire rotating element is carried by a thrust bearing and two shaft bearings. The upper shaft bearing is of the ball type and the lower one is of the sleeve type, babbitt lined. Each of these bearings is lubricated by oil supplied from the pump discharge chamber. The thrust bearing carries the weight of the entire rotating element.

The motor shaft is connected to the pump shaft by a rigid coupling.

SPECIFIC COURSE FOR ENGINEERS MECHANICAL MAINTENANCE MODULE 14TURBINE LUBE & CONTROL OIL LESSON 4 PAGE 1

LIST OF PARTS

1. Nut2. Washer3. Coupling Head (lower)4. Coupling head (upper)5. Bolt6. Motor7. Bolt8. Washer9. Nut10. Key11. Taper Pins12. Key 13. Pump shaft14. Motor support15. Pump shaft bearing (lower)16. Stud 17. Washer18. Bolt19. Washer20. Nut21. Set screws22. Pump Body oil seal ring (upper)23. Pump impeller24. Pump Impeller oil seal ring (lower)25. Pump body oil seal ring (lower)26. Pump body (upper)27. Strainer28. Pump body (lower)29. Set screw30. Special Nut31. Set screw32. Washer33. Nut34. Stud35. Set Screw36. Key37. Pump Impeller oil seal ring (upper)38. Set screw

MECHANICAL MAINTENANCE MODULE 14 SPECIFIC COURSE FOR ENGINEERSLESSON 4 PAGE 2 TURBINE LUBE & CONTROL OIL

Fig. 14-4-1.


AUXILIARY OIL PUMP OVERHAUL, INSPECTION AND MAINTENANCE

1. Check if PTW has been issued.2. Verify electrical and instrument connections if they were isolated.3. Check the oil inside the tank if it is already drained.4. De-couple the pump from motor.5. Coordinate with EMS in removing of motor.6. Obtain the Gas free certificate before opening manway cover.7. Open manway cover and place the hand lamp inside.8. Remove all bolts and nuts securing discharge flange.9. Loosen and remove all base bolts.10. Position the crane hook above the unit with accessories and fix to the base,

then slowly lift up the unit using chain block. If the unit is cleared from the system use crane to pull out completely and place in a safe area over a plywood sheet in horizontal position.

11. Using dial indicator take initial axial float of the shaft and record for reference.

Disassembly

12. Remove the pump half coupling by extracting first the taper pin lock and pull off the coupling using a coupling puller.

13. Detach the suction screen by removing all cap screws on the outer surface of suction eye.

14. Loosen and remove all bolts securing pump body and body cover.15. Screw off the impeller nut set screw, then loosen the impeller nut and

remove.16. Pull out the impeller together with the key.17. Remove the pump cover from motor support.18. Pull off the shaft from motor support.19. Clean and inspect thoroughly all parts for any damage or excessive wear.

Replace if necessary.20. Check the run-out of the shaft using dial indicator at several points over a

two rollers in both ends. If run out exceeds more than 0.05 mm repair or replace the shaft as required.

21. Measure the bore bearing and the wear rings of impeller and casing. Refer to the enclosed table for tolerance design of wear rings. Replace the bearing and or wear rings if the clearance exceeds the design.


Re-assembly

22. If all parts are completed and ready, re-assembly the unit in the reverse order of disassembly.

23. Insert the shaft to motor support and fix the pump cover.24. Fix the impeller to the shaft with key, then place the nut and tighten to the

required torque. Screw in the impeller nut set screw.25. Install the pump body to pump cover and tighten all bolts equally across to

balance the level.26. Fix back the coupling half in pump side and lock the taper pin.27. Rotate the shaft by hand to check for any seizing or other disturbances

during operation.28. Check the axial float and rectify if nay problem present.29. Fix back the suction screen.30. Arrange crane operator to lift up the unit and place back to the system. Be

sure to fix back the foundation gasket during installation.31. Tight all discharge flange bolts with a new gasket.32. Check the level base of the unit.33. Arrange EMS, Operation and T & I to re-install the prime mover and to test

run the unit after installation and reconnection of power supply to check the rotation and to get vibration reading respectively.

34. Align the motor with respect to the pump and couple after alignment.35. Clean up the area.36. Cancel PTW.37. Fill up the appropriate Maintenance Management System report from. This

may be obtained from Maintenance Planning Group.

Wear Ring Clearance Table.

Casing Inner

Diameter (mm)

Maximum Clearance

Between Case and Impeller (mm)

Wear ring Clearance (mm)

Minimum MaximumUp to 50 2.1 0.260 0.350Between 50 and 80 2.3 0.285 0.380Between 80 and 125 2.5 0.320 0.420Between 125 and 160 3.0 0.380 0.500Between 160 and 200 3.5 0.430 0.560Between 200 and 250 4.0 0.490 0.630Between 250 and 315 4.5 0.550 0.710Between 315 and 400 5.0 0.620 0.800Between 400 and 500 5.5 0.700 0.900Between 500 and 630 6.0 0.800 1.000


OIL PUMP (MOTOR DRIVEN)

The unit is provided with two vertical shaft centrifugal type pumps, shown in Fig. 14-4-2 one is an A.C. motor driven pump, the other one is the emergency D.C. motor driven pump. The A.C. pump supplies oil to the system for lubrication when the turbine is on the rotor turning gear. The D.C. pump is provided as an emergency backup in case all A.C. power in the plant is lost.

The pumps are designed for mounting on the oil reservoir and the pump runner is always below the minimum oil level, thus insuring a positive suction head.

The runner 17 is keyed on the lower end of the pump shaft and further secured by the nut 24. The body and body liner 15 and 27 fit around the runner with a close clearance and limit oil leakage from the discharge side to the suction. The liners are held in place by set screws 16 and 26 and can be replaced if necessary. The strainer 22, which is made of perforated plates, protects the pump runner from coarse dirt or debris. The bearing 28 is made in halves and held in place by studs. It is submerged in oil at all times.

The pump shaft is connected to the driving motor by a rigid coupling. The motor is of standard design with two ball bearings. The upper one serves as a thrust bearing, carrying the weight of the rotating elements and the thrust of the pump runner. These bearings are lubricated by grease which is injected through external pipe connections provided for this purpose. Grease should be added periodically, depending on the total time the motor operates so as to keep the bearings well lubricated.

Avoid adding too much, however, as the excess will be forced outward along the shaft. The kind of grease used should be in accordance with the instructions attached to the motor when it is received from the factory.

The pump support 10 is bolted to the top of the oil reservoir. When dismantling for inspection it is necessary to break the flanged joint between the pump body and the oil discharge pipe before lifting the unit out of the reservoir. After removing the pump from the reservoir all parts are readily accessible, as will be noticed in the illustration.


LIST OF PARTS

1. Pump shaft coupling half key2. Coupling nut3. Lockwasher4. Pump shaft coupling half (male)5. Pump shaft coupling half (female)6. Coupling bolt7. Motor8. Motor shaft coupling half key9. Taper pin10. Pump support 11. Pump shaft12. Bolt13. Lockwasher14. Nut15. Pump body liner16. Set screw17. Pump runner18. Pump runner key19. Pump body20. Locknut21. Stud22. Pump runner strainer23. Set screw24. Pump runner nut25. Pump inlet casing26. Set screw27. Pump inlet casing liner28. Pump shaft bearing29. Lock washer30. Tap bolt


Fig. 14-4-2.


TURNING GEAR OIL PUMP OVERHAUL, INSPECTION AND MAINTENANCE

38. Check if PTW has been issued.39. Verify electrical and instrument connections if they were isolated.40. Check the oil inside the tank if it is already drained.41. De-couple the pump from motor.42. Coordinate with EMS in removing of motor.43. Obtain the Gas free certificate before opening manway cover.44. Open manway cover and place the hand lamp inside.45. Remove all bolts and nuts securing discharge flange.46. Loosen and remove all base bolts.47. Position the crane hook above the unit with accessories and fix to the base,

then slowly lift up the unit using chain block. If the unit is cleared from the system use crane to pull out completely and place in a safe area over a plywood sheet in horizontal position.

48. Using dial indicator take initial axial float of the shaft and record for reference.

Disassembly

49. Remove the pump half coupling by extracting first the taper pin lock and pull off the coupling using a coupling puller.

50. Detach the suction screen by removing all cap screws on the outer surface of suction eye.

51. Loosen and remove all bolts securing pump body and body cover.52. Screw off the impeller nut set screw, then loosen the impeller nut and

remove.53. Pull out the impeller together with the key.54. Remove the pump cover from motor support.55. Pull off the shaft from motor support.56. Clean and inspect thoroughly all parts for any damage or excessive wear.

Replace if necessary.57. Check the run-out of the shaft using dial indicator at several points over a

two rollers in both ends. If run out exceeds more than 0.05 mm repair or replace the shaft as required.

58. Measure the bore bearing and the wear rings of impeller and casing. Refer to the enclosed table for tolerance design of wear rings. Replace the bearing and or wear rings if the clearance exceeds the design.


Re-assembly

59. If all parts are completed and ready, re-assembly the unit in the reverse order of disassembly.

60. Insert the shaft to motor support and fix the pump cover.61. Fix the impeller to the shaft with key, then place the nut and tighten to the

required torque. Screw in the impeller nut set screw.62. Install the pump body to pump cover and tighten all bolts equally across to

balance the level.63. Fix back the coupling half in pump side and lock the taper pin.64. Rotate the shaft by hand to check for any seizing or other disturbances

during operation.65. Check the axial float and rectify if nay problem present.66. Fix back the suction screen.67. Arrange crane operator to lift up the unit and place back to the system. Be

sure to fix back the foundation gasket during installation.68. Tight all discharge flange bolts with a new gasket.69. Check the level base of the unit.70. Arrange EMS, Operation and T & I to re-install the prime mover and to test

run the unit after installation and reconnection of power supply to check the rotation and to get vibration reading respectively.

71. Align the motor with respect to the pump and couple after alignment.72. Clean up the area.73. Cancel PTW.74. Fill up the appropriate Maintenance Management System report from. This

may be obtained from Maintenance Planning Group.

Wear Ring Clearance Table.

Casing Inner

Diameter (mm)

Maximum Clearance

Between Case and Impeller (mm)

Wear ring Clearance (mm)

Minimum MaximumUp to 50 2.1 0.260 0.350Between 50 and 80 2.3 0.285 0.380Between 80 and 125 2.5 0.320 0.420Between 125 and 160 3.0 0.380 0.500Between 160 and 200 3.5 0.430 0.560Between 200 and 250 4.0 0.490 0.630Between 250 and 315 4.5 0.550 0.710Between 315 and 400 5.0 0.620 0.800Between 400 and 500 5.5 0.700 0.900Between 500 and 630 6.0 0.800 1.000


TURNING GEAR OVERHAUL INSPECTION AND MAINTENANCE

PREPARATION

1. Obtain PTW 2. Make sure that all relevant valves are properly close and tagged.3. Make sure that engaging lever is already disengaged.

DISMANTLING PROCEDURES

4. Arrange with EMD to disconnect the related electrical connections.5. Arrange with IMD to disconnect the instruments and its connections.6. Remove bolts holding hand wheel cover and adopter7. Remove hand wheel cover.8. Remove base bolts of the unit the from housing.9. By using crane, chain blocks, slings, shackle and eye bolts, lift unit from its

position and place in a safer area.10. Take out the engaging lever guard and remove rubber bellow.11. Position the crane with connections above the motor and fix slings.12. Remove motor anchor bolts and pull out the motor.13. Arrange with EMD to overhaul or service the motor.14. Check the condition of coupling, rubber insert and hand wheel bellow.

Replace if necessary.15. Loosen align screw on the lower half and remove coupling.16. Remove thrust bearing cover with packing.17. Check thrust bearing and guide bearing. Replace with new one if required.18. Remove pin from the main pinion shaft.19. Check gears and replace the bush if required.20. Pull out reduction gear. Remove spacer ring and shaft.21. Take out stop ring of the worm gear. Remove worm gear and pinion shaft.22. Remove retaining screw holding the slash pinion shaft and pull out the shaft,

leaving slash pinion gear in the position.23. Inspect all bushing, shaft and contact surface of the respective gear for any

damage and excessive wear. Replace the part as necessary.24. Clean all parts thoroughly.25. Check condition of Fulcrum, pneumatic unit, bellow and springs. Repair or

replace as necessary.

ASSEMBLY PROCEDURES

26 Assemble all parts in the reverse order of dismantling.27 Apply silicon liquid sealant to the housing joint surfaces.28 Fix motor unit into to the base.29 Arrange with EMD to connect all electrical connection.30 Arrange IMD to fix all instruments and its connections.31 Make good house keeping around the area32 Clear PTW33 Fill up the appropriate Maintenance Management system report from. This

may be obtained from maintenance planning group.


LIST OF PARTS

1 Worm gear 27 Bushing2 Worm gear pinion 28 Spacer ring3 Guide bearing assembly 29 Key4 Worm 30 Snap ring5 Thrust bearing assembly 31 Spacer ring6 Coupling assembly 32 Bushing7 Turning gear plate 33 Retaining screw8 Turning gear housing 34 Bushing9 Stud 35 Spacer ring10 Nut 36 Bushing11 Hand operating mechanism 37 Spacer ring12 Electric motor 38 Plate assembly13 Socket head screw 39 Bushing14 Bellows 40 Bushing15 Clash pinion gear 41 Bushing16 Clash pinion shaft 42 Key17 Reduction gear 43 Stop ring18 Main pinion 44 Spacer ring19 Engaging lever 45 Spacer ring20 Shift lever handle 46 Pneumatic cylinder21 Name plate 47 Limit switch22 Cover support 47a Limit switch23 Spring 47b Limit switch24 Lever cover 48 Pin25 Trigger pin 49 Clevis26 Trigger 50

51Tubing SupportTubing assembly


Fig. 14-4-3. Main turbine Turning Gear.


Fig. 14-4-4. Main turbine turning gear.


Fig. 14-4-5. Main turbine turning gear Section E-E.


GOVERNOR PEDESTAL ASSEMBLY

Fig. 14-4-6 shows the Governor pedestal assembly. It is located in the front end of the turbine and supports the fore end of the turbine rotating and stationary parts.

The turbine outer casing is supported on the center line by two arms which are cast integrally at the force end top of the base half, and rest on keys on the pedestal to slide freely. The pedestal base is connected to the outer casing base by an “H” beam and permitted to slide axially in response to temperature changes.

The turbine rotor is supported by the No.1 bearing. On the fore end of the extension shaft, main oil pump impeller, governor impeller and over speed trip weight are mounted.

Governor consoles are attached to each side of the thrust pedestal to install miscellaneous control apparatus. These are described in detail in separate leaflets.

MAIN OIL PUMP AND GOVERNOR IMPELLERS

Fig. 14-3-6 shows the arrangement of the two impellers located on the turbine shaft, between the thrust bearing and the overspeed trip mechanism. The impeller 21 on the left serves as the main oil pump. It is of the conventional centrifugal type and discharges at a pressure of approximately 22 atg at normal operating speed with 0.85 atg suction pressure. This impeller is not self priming. While operating at normal speed, its suction is supplied by an ejector which utilizes high pressure oil from the impeller discharge as the operating medium. During the starting periods, this impeller suction is supplied by the motor driven auxiliary oil pump.

The governor impeller 22 consists of a hollow cylindrical body with a series of radially inser5ted tubes connecting the inner chamber with the impeller chamber. The inner chamber is also connected to the drain chamber by a series of radial holes.

An adjustable orifice admits a sufficient quantity of high pressure oil from the main oil pump discharge to the annular chamber around the governor impeller seal sleeve 23 to maintain about 60 LPM. Of flow through the impeller holes to the drain chamber. With the impeller rotating, the centrifugal force of the oil in the radial tubes opposes the flow of oil through the holes and maintains a pressure in the governor impeller discharge cavity which varies as the square of the turbine speed (at normal speed this pressure is about 2.1 to 2.2 atg). This impeller acts as a rotating relief valve, maintaining a pressure corresponding to the centrifugal force of the column of oil in the impeller holes and by pass to drain any excess oil supplied through the orifice above that required to maintain the pressure in the governor5 impeller discharge chamber around the seal sleeve 23.


Fig. 14-4-6. Pedestal Assembly.


The governor impeller discharge cavity is connected to the governor transformer and the pressure changes in this cavity produced by speed changes constitute the governing force which controls the governing valve servomotors. If the turbine speed increases, the governor impeller discharge pressure increases and if it decreases, this pressure decreases.

It is important to check the pressure in the governor impeller discharge periodically. If a gradual drop in this pressure is noticed, it is an indication of either excessive wear in the seal sleeve or gradual plugging of the supply orifice. The variable orifice should be opened to compensate for ordinary wear.

This adjustment may best be accomplished with the turbine running at no load with its normal speed being held by means of the throttle valve. The orifice screw is then turned inward until the impeller pressure just falls sharply. It is then backed outward from this point about 5 turns and locked in the position.


MAIN OIL PUMP AND GOVERNOR IMPELLERS

1. Key 2. Oil Baffle3. Ring4. Ring5. Disc.6. Plate7. Spring8. Bolt9. Screw10. Bolt11. Washer12. O-Ring13. O-Ring14. Bolt15. Bolt16. Washer17. Dowel Pin18. Spacer19. Pump casing (upper half)20. Pump casing (lower half)21. Impeller22. Governor impeller23. Governor impeller seal sleeve24. Bolt25. Nut26. Taper Pin27. Cover28. Plug29. Needle Valve30. Plug31. Gasket32. Cover33. Plug34. Overspeed Trip35. Oil Seal Ring36. Oil Seal Ring37. Oil Seal Ring 38. Oil Seal ring


Fig. 14-4-7. Main Oil Pump & governor Impeller.


RELIEF VALVE AND ORIFICE

The relief valve and orifice shown in Fig. 14-3-7 are assembled on a valve body (14) and mounted in a block which is integral with the internal piping in the high pressure turbine governor end pedestal base.

The quantity of high pressure of oil admitted to the chamber in the block is determined by the setting of the orifice screw 2 and the pressure maintained in the chamber is established by the loading of the compression spring 17, 18 acting downward on the cup valve 15.

Two high pressure oil outlets from the chamber supply the governor impeller and the control devices. The oil supplied be the control devices passed through a high pressure filter 12 shown in Fig.

The orifice screw 2 and the adjusting screw 19 should be set to maintain an oil pressure of 20 atg in the chamber.


LIST OF PARTS

1. Valve Seat2. Orifice Screw3. Screw adjusting nut4. Bolt5. Screw bush6. Plug7. Plug8. Plug9. Straight Pin10. Hexagon Socket Head Bolt11. Spring washer12. Filter13. Valve case14. Valve body15. Valve16. Loading spring seat17. Valve loading spring (outer)18. Valve loading spring (inner)19. Loading spring adjusting screw20. Screw adjusting nut


Fig. 14-4-8. Relief Valve and Orifice.


GOVERNOR IMPELLER, OIL RELIEF VALVE AND MULTIPLE ORIFICE

GOVERNOR IMPELLER SLEEVE

21. Check governor impeller sleeve clearance.21. If clearance is more than the design limit (0.05 to 0.15 mm), the following

action should be taken.22. Remove the stud shaft23. Polish the coupling at the place of rubbing of vibration pickup if required.24. Replace or refurbish the governor impeller sleeve if necessary.25. Fix back the stud shaft and align it.

MAIN OIL PUMP 26. With reference to the Figs. 14-4-9, 14-4-10 & 14-4-11 “Main Oil Pump and

Governor Impeller” , disassemble the main oil pump.27. Clean and inspect all the parts.28. Inspect the impeller for corrosion and excessive clearance.29. Checking wearing ring clearance and replace if necessary.30. Repair or replace any parts if required.31. Assemble the pump.32. Put back pedestal covers and maintain oil deflector seal clearance at in and

at out board.


Fig. 14-4-9. Main oil pump and governor impeller.


Fig. 14-4-10. Main oil pump and governor impeller


MAIN OIL PUMP, GOVERNOR IMPELLER AND OIL SEAL CLEARANCES

With reference to the diagram below, measure the clearances marked A,B,C,D,E, and F. Record the measured values on the Main oil, Governor Impeller and oil seal clearances Record.

Fig. 14-4-11. Main oil pump and governor impeller and oil seal clearances.


Fig. 14-4-12. Record of Inspection Main Turbine Phase-2 Power House –B.


NOTE:

The oil relief valve is inside the front pedestal of the Turbine.

1. With reference to the Fig. 14-4-13, disassemble the oil relief valve.2. Clean and inspect all the parts.3. Lap the cup valves.4. Replace all the gaskets.5. Repair or replace any parts if required.6. Re-assemble the oil relief valve.7. Fill out the appropriate Maintenance Management System Report Form.

This form may be obtained from the Maintenance Planning Group.

Fig. 14-4-13. Oil Relief Valve.


PARTS LIST

1. Gasket2. Plate3. Dash pot piston4. Support lever5. Piston retaining nut6. Adjusting screw support stud 7. Adjusting nut8. Adjusting screw support9. Support retaining nut10. Loading spring adjusting screw11. Lock nut12. Spring seat (upper) 13. Valve loading spring14. Spring seat (lower) 15. Retaining screw16. Retaining screw17. Spacer18. Lock nut19. Orifice screw20. Cup valve screw21. Screw adjusting nut22. Nut23. Cup valve24. Cup valve seat25. Gasket26. Filter27. Filter retaining screw28. Reducer

MULTIPLE ORIFICE OVERHAUL

Note:

The Multiple Orifice and check valve is inside the front pedestal of the turbine.

1. With reference to the Fig. 14-4-14, disassemble the multiple orifice2. Clean and inspect all the parts paying special attention to the orifice.3. Repair or replace any parts if necessary.4. Re-assemble the multiple orifice and check valve.5. Fill out the appropriate Maintenance Management System Report Form.



Fig. 14-4-14. Multiple Orifice and Check Valve.


MAIN GOVERNOR TRANSFORMER, SPEED CHANGER AND LOAD LIMITER VALVE OVERHAUL

MAIN GOVERNOR TRANSFORMER AND SPEED CHANGER OVERHAUL

1. With reference tot he Fig. 14-4-15 * 14-4-16, disassemble the Governor Transformer and Speed changer.

2. Clean and inspect all the parts paying special attention to the cup valves, compression springs and bellows.

3. Check the eccentricity of the stems.4. Replace all the gaskets and “O” rings.5. Clean and inspect the orifices.6. Arrange with EMS for the overhaul of the adjusting spindle drive motor.7. Report any defects found.8. Repair or replace any parts if necessary.9. Re-assemble the Governor Transformer and speed changer.10. After overhauling the speed changer, adjust the minimum and maximum oil

pressure setting as per design values, first mechanical and then the electrical limits.

11. Adjust the relief valve to 3.8 to 4.0 bar.12. Simulate the Speed changer to the actual take over to 3400 RPM.13. Check the actual curve and the design curve of the speed changer pressure

versus governor impeller pressure.14. Check the actual curve and the design curve of speed changer pressure

versus servo opening.15. Fill out the appropriate Maintenance Management System Report Form.

This form may be obtained from the Maintenance Planning group.


Fig. 14-4-15. Main Governor Transformer and speed changer.


Fig. 14-4-16. Main Governor Transformer and speed changer.


PARTS LIST

1. Governor cup valve seat2. Governor cup valve3. Governor cup valve4. Governor transformer bellows lever 5. Governor speed changer spring seat (lower)6. Governor speed changer spring (inner)7. Governor speed changer spring seat ball bearing.8. Governor speed changer spring seat (inner)9. Governor speed changer spring (outer)10. Governor speed changer shaft11. Set screw12. Governor housing13. Gasket14. Governor housing cover15. Governor speed changer stop pin16. Governor speed changer stop 17. Governor speed changer stop screw18. Governor speed changer name plate19. Governor speed changer hand wheel20. Governor speed changer hand wheel retaining screw21. Governor speed changer stop retaining screw22. Governor speed changer stop screw23. Governor speed changer stem bushing24. Governor speed changer stop pin25. Governor speed changer friction clutch collar26. Governor speed changer friction clutch washers27. Governor speed changer worm wheel28. Governor speed changer friction clutch spring29. Governor speed changer friction clutch spring seat30. Governor speed changer shaft bushing and spring seat (outer)31. Gasket 32. Cover plate33. Gasket34. Plug 35. Guide rod36. Check valve37. Gasket38. Adapter plate39. Valve seat40. Cup valve41. Compression spring42. Cover43. Socket head screw44. Spring seat45. Gasket46. Governor speed changer worm and worm wheel shaft47. Governor speed changer worm and worm wheel shaft bushing48. Governor speed changer worm and worm wheel bushing49. Governor speed changer worm and worm wheel 50. Governor speed changer worm and worm wheel shaft set screw51. Retaining bolts52. Governor transformer bellows


53. O-Ring54. Spacer55. Governor speed changer motor shaft extension56. Governor speed changer worm spacer57. Governor speed changer worm58. Governor speed changer worm set screw59. Governor speed changer motor shaft bushing60. Governor speed changer motor61. Orifice plug62. Control block63. Orifice plug64. Orifice plug65. O-ring66. O-ring67. O-ring

LOAD LIMIT VALVE OVERHAUL (C – 6)

1. With reference tot he Figs. 14-4-17, disassemble the load limit valve2. Clean and inspect all the parts paying special attention to the cup valves and

compression springs.3. Report and repair or replace any defects found.4. Lap and blue match the cup valves.5. Check the eccentricity of the stems.6. Replace all the gaskets and O rings.7. Arrange with IMS to overhaul and adjust the load limit valve limit switches.8. Re-assemble the load limit valve.9. Fill out the appropriate Maintenance Management System Report Form.



Fig. 14-4-17. Load Limit Valve.


Fig. 14-4-18a. Load Limit Valve.


PARTS LIST

1. Load limit valve cup valve seat2. Load limit valve cup valve bot3. Castle nut4. Load limit valve cup valve5. Load limit valve cup valve diaphragm6. Load limit valve diaphragm supporting ring (lower)7. Load limit valve diaphragm supporting ring (upper)8. Load limit valve spring seat (lower)9. Load limit valve compression spring10. Load limit valve spring seat (upper)11. Load limit valve body12. Load limit valve adjusting spindle bushing13. Set screw14. Gasket15. Load limit valve body cover16. Stop pin17. Stop set screw18. Load limit valve adjusting spindle hand wheel19. Load limit valve adjusting spindle20. Stop screw21. Stop screw22. Stop pin23. Load limit valve clutch collar24. Washers25. Load limit valve worm wheel26. Load limit valve clutch spring27. Load limit valve clutch spring seat28. Gasket29. Cover plate30. Gasket31. Guide rod32. O ring33. Load limit valve34. Load limit valve worm and worm wheel bushing 35. Load limit valve motor shaft extensions36. Load limit valve worm spacer37. Set screw38. Load limit valve worm39. Load limit valve worm wheel shaft bushing40. Load limit valve worm and worm wheel41. Load limit valve worm and worm wheel shaft42. Set screw 43. Load limit valve shaft bushing44. Load limit valve motor45. Orifice plug46. Pipe plug47. Rod


LOAD LIMITER OVERHAUL (C – 8)

1. Verify, if the PTW has been issued.2. In coordination with EMS, disconnect load limiter motor and its limit switches.

Disassembly

3. With the reference to Fig. 14-4-18 a ~ 14-4-20, unscrew the set screw of hand wheel and stop plate, then remove hand wheel from spindle.

4. Disassemble the load limiter body cover from body and remove the body from control block.

5. Care should be taken while disassembling due to the small parts and plate in safe area.

6. Loose the lock set screw and disconnect the worm wheel together with the shaft. Later loosing the set screw, disconnect the spacer, worm and motor shaft extension.

7. Unscrew the load limiter valve spindle with clutch from bushing.8. Loose the set screw, then separate the clutch from shaft with the clutch

position marked on the shaft.9. Clean the parts and observe the condition of the spring including the sliding

spring, change with a new one if necessary.10. Fix back the clutch in the reverse sequence from step # 8 ~ 7.11. Check the clutch collar in the clutch housing if it slide freely.12. Inspect the condition of the thread between bushing and spindle.13. Blue match the cup valve and cup valve seat to verify the contact surface,

then lap if the contact is not perfect.14. Clean the orifice with cleaning solvent and blow high air pressure to remove

all blockage from the hole.15. Confirm the proper spring seating by peeping through cover plate while re-

assembly.

NOTE:

Gaskets must be replace with a new one with a thickness of 0.8 mm and also O-rings from the covers of drain and filtered HP oil.

The play for worm and worm wheel must be maintain not less than 0.05 mm.

Re-assembly

16. When all parts are ready and completed, re-assemble the unit in the reverse sequence of disassembly.

17. Adjust the stopper pi9n and stop plate at the time of simulation (0.80 Bar ~ 4.40 Bar)

18. Arrange EMS to install back the motor and limit switches with the limit switches set to cut-points earlier to mechanical stopper.

19. Clear the working area.


Fig. 14-4-18b. Load Limiter.


Fig. 14-4-19. Load Limiter.


Fig. 14-4-20. Load Limit Valve


AUXILIARY GOVERNOR, EXHAUST PRESSURE REGULATOR

1. Verify if the PTW has been issued2. Disassemble the auxiliary body along with the valve spindle, hand wheel,

stem guide and lock nut.3. Separate the spring seat upper and lower.4. Disconnect the cup valve with fulcrum one end from the anchor and the

other end from governor impeller transformer below and spacer.5. Remove the fixing screws for pressure transformer bellow and separate the

O-ring.6. Release the spring with spring retainer and remove both relief valve cup and

spring as well.7. Loosen and remove the accumulator block bolts, then disconnect block from

both sides.8. Remove the auxiliary diaphragm retainer, then take out with its support

including the spring and compression rod.9. Separate the diaphragm from spring seat and diaphragm support.10. Check the condition of the diaphragm including the spring.11. Remove the auxiliary governor accumulator bellows at both sides covers and

unfasten the bellow.12. Inspect the bellow spring etc.13. Disconnect the test lever unit and check up the components such as: valve

guide, test valve, pin and spring.14. Replace the gland packing rings, including the gaskets from accumulator

below cover, auxiliary governor body and accumulator block with a thickness of 0.8 mm.

15. Renew all O-rings from auxiliary governor test valve lever and control oil orifice plug.

16. Clean and inspect all parts and if necessary, replace all worn out and amage parts with anew one.

17. When all parts are ready and completed, proceed to re-assemble in the reverse sequence of disassembly with proper positions and settings.

18. Use proper lubricant for gaskets and O-rings.19. Clean up the working area.


SPARE PARTS

1. Accumulator Bellows Housing2. Stop Pin3. Accumulator Bellows Assembly 4. Accumulator Bellows Spring5. Gasket6. Accumulator Bellows Cover7. Accumulator Bellows Spring Seat8. Test Valve guide9. Test valve10. Cup valve Compression rod11. Transformer Bellows 12. O-Ring 13. Spacer14. Operating Lever Assembly15. Spring Seat (Lower)16. Operating Lever Spring17. Spring Seat (Upper)18. Handwheel Stem Guide19. Handwheel20. Pin21. Handwheel Shaft Lock Nut22. Handwheel Shaft Guide Lock Nut23. Operating lever assembly cover24. Handwheel Shaft Gasket25. Gasket26. Relief Valve27. Relief Valve Spring28. Relief Valve Spring Retainer29. Control Block30. Set screw31. Gasket 32. Globe Valve33. Pressure Gauge34. Test Valve lever bracket35. Test valve packing gland36. Test valve lever link37. Test valve lever stop38. Gasket39. Spring Retainer40. Dump cup valve41. Lock nut42. Dump valve cover43. Compression spring44. Check valve45. Dump cup valve guide bushing46. Dump cup valve seat47. Gasket48. Drain cover 49. Diaphragm support50. Diaphragms retainer51. Diaphragm52. Spring seat


53. Compression spring54. Compression spring55. Cup valve seat56. Cup valve57. Lock nut58. Cup valve stem59. Test valve lever60. Pin61. O-ring62. O-ring63. O-ring64. Governor impeller discharge orifice plug65. Pin66. Male adapter67. CV Ring68. Male adapter69. CV Ring70. Test valve spring71. Pin72. Lock nut73. Compression pin nut74. Control oil orifice plug75. O-ring


Fig. 14-4-21. Auxiliary Governor and dump Valve.


Fig. 14-4-22. Auxiliary Governor and Dump Valve.


EXHAUST PRESSURE REGULATOR OVERHAUL (C – 6)

1. Arrange with IMS for the overhaul of the pneumatic actuator, positioner and air filter regulator.

2. With reference to the Fig. 14-4-23, disassemble the exhaust pressure regulator.

3. Clean and inspect all the parts paying special attention to the cup valves, the seating of the cup valve and compression springs.

4. Clean and inspect the oil supply orifice.5. Inspect the cup valve diaphragm for rupture and replace if necessary.6. Lap and blue match the cup valves.7. Replace all the O rings.8. Repair or replace any parts if necessary.9. Re-assemble the exhaust pressure regulator.10. After the overhaul, in coordination with IMS (O/H) and operations, carry out

the simulation test of the Exhaust Pressure Regulator and ensure that it follows the design values.

11. Fill out the appropriate Maintenance Management System Report From. This form may be obtained from the Maintenance Planning Group.


Fig. 14-4-23. Exhaust Pressure Regulator.


SPARE PARTS LIST

1. Pneumatic actuator2. Pneumatic positioner3. Filter regulator4. Pneumatic actuator rod5. Pneumatic actuator rod end6. Connecting link pin7. Connecting link8. Hydraulic regulator operating lever9. Lever fulcrum pin10. Lever fulcrum block11. Spring adjusting stem12. Adjusting stem lock nut13. Spring seat (upper)14. Compression spring15. Spring seat (lower)16. Cup valve diaphragm17. Cup valve18. Cup valve seat19. Hydraulic regulator20. Regulator cut out screw support21. Regulator cut out screw22. Regulator cut out screw lock nut23. Regulator cut out screw hand wheel24. Orifice plug 25. Check valve26. Roller bearing O-rings.


Fig. 14-4-24. Exhaust Pressure Regulator.


1. Confirm that the PTW has been issued before starting the job.2. Arrange with IMS to disconnect the electrical operated air solenoid valve and fitting

from cut-off valve.3. With reference to Fig. 14-4-24 remove the front and rear covers, taking care of the

gasket, then clean with a cleaning solvent (perfect transparency is must).4. Remove the split pin and unscrew the stopping nut.5. Unscrew the locknut and take out the adjusting screwed bar including the spring seat

and compression spring.6. For reference during final assembly, record either height or threads remain over the

nut on bar stopper.7. Loosen and remove the nuts on the lower and disconnect the stopper from lever.8. Don’t disturb the adjusting bolt without any reason.9. Remove the bolt, spring washer and washer.

10. Now the fulcrum lever is free, take out the fulcrum lever along with the damper piston, adjusting bolt, plate spring etc.

11. Unscrew air bellow carefully and if observed any signs of damage on this part, replace with a new one.

12. Inspect the cup valve and cup valve seat for any sign of major damage. Lap, using special tool with diamond lapping paste to a mirror finish and verify the contact surface by blue matching. If lapping is not possible, replace with a new one.

13. Clean all internal parts and inspect for any damage.14. Loose cut off air cylinder cover bolts and take out slowly so that the compression

spring can be handled easily.15. Open the drain plug of cut off valve and from the top side, take out the piston with

cut off plunger.

16. Clean the bushing of cut-off and inspect for any scoring or damage over the cut off plunger and bushing. Replace with a new one if observed any.

17. Arrange T & I to inspect after final cleaning including springs, spring plates, orifice plugs, multi holed plates etc.

18. When all parts are ready and completed, re-assemble the E.P.R. in the reverse sequence of disassembly.

19. Replace all O-rings and gaskets.20. Clean and re-assemble the final low oil selector relief valve.21. Wound Teflon tape to all removed plugs and fix back to their respective place.22. Clean up the working area23. Arrange IMS to reconnect the electric operated air solenoid valve and its piping.24. Fill up the appropriate Maintenance Management system Report form. This form

may be obtained from the Maintenance Planning group.


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