1. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
WHAT IS PHASE ANGLE Ø
360 0
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

2. USES OF PHASE ANGLE MEASUREMENT
A.K.SINHA, DGM (TURBINE)
USES OF PHASE ANGLE MEASUREMENT
BALANCING
STRUCTURE MOTION STUDY
DETECTION OF RESONANCE FREQUENCY
RUN UP & RUN DOWN BEHAVIOUR
BODE PLOT
HEALHINESS OF MATING SURFACES OF TWO VIBRATING MASSESS
UNDERSTANDING THE DEFLECTION MODE OF THE SHAFT
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

3. ` BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
STRUCTURE MOTION STUDY
REAR
220
FRONT
FRONT
220
212
127
107 87 56 24 7
-14
-25
REAR
245
228
165
112 96 53
245
230 1
209
170 2
138 3
120
101
4/5 94 6 71 7
LEFT SIDE
RIGHT SIDE 8 63 51 9 10 11 12 13 9 10 11 12 13 ` 19 20 21 22 23 19 20 21 22 23 14 15 16 17 18 14 15 16 17 18 33 11 -9
-23
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

4. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
STRUCTURE MOTION STUDY
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

5. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
HEALHINESS OF MATING SURFACES OF TWO VIBRATING MASSESS 3 2 1 7 8 9 6 5 4
GENERATOR SIDE B
BASE PLATE D
LEFT 12 C 15 11 14 A
RIGHT 21 10 13 20 18 17 19 16
SECONDARY GROUT
TURBINE SIDE
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

6. B1 B2 B3 B4 BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
UNDERSTANDING THE DEFLECTION MODE OF THE SHAFT B1 B2 B3 B4
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

7. Case Studies on Vibration Problems in Steam Turbine Generators
A.K.SINHA, DGM (TURBINE)
Case Studies on
Vibration Problems in Steam Turbine Generators
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

8. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN
500 MW TG SETS
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

9. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
PROBLEM
HIGH HP FRONT SHAFT AND BEARING PEDESTAL VIBRATION
OBSERVATIONS
(A) FREQUENCY ANALYSIS CARRIED OUT WHICH INDICATED
PREDOMINANT 1-X VIBRATION COMPONENTS FOR BOTH SHAFT AND BEARING PEDESTAL VIBRATION
STEADY PHASE ANGLE
(B) BEARING PEDESTAL VIBRATIONS AND SHAFT VIBRATIONS WERE HAVING RISING TENDENCY AT RATED SPEED HOWEVER, THEIR RATIO WAS FOUND TO BE ALMOST CONSTANT
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

10. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
ANALYSIS
PREDOMINANT 1-X VIBRATION WITH SLIGHT CHANGE IN PHASE ANGLE INDICATED THERE WAS UNBALANCE IN THE ROTOR SYSTEM LEADING TO INITIATION OF MINOR RUB
MAIN SOURCE OF VIBRATION WAS HIGHER DYNAMIC LOADING FROM THE SHAFT WHICH WAS GETTING TRANSMITTED TO BEARING
ACTION TAKEN
TO REDUCE THE HP FRONT SHAFT VIBRATION LEVEL, INSITU BALANCING WAS CARRIED OUT USING LP ROTOR BALANCING PLANES
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

11. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
RESULT OF INSITU BALANCING
HP SHAFT VIBRATION BROUGHT DOWN TO STEADY VALUE OF 120 MICRONS, 0-PK FROM EARLIER VALUE OF MICRONS, 0-PK
HP FRONT BEARING VIBRATION CAME DOWN INITIALLY TO 15 MICRONS, 0-PK AT 3000 RPM FROM EARLIER VALUE OF 25 – 40 MICRONS, 0-PK
LATER, WITHIN 2-3 HOURS OF OPERATION, HP FRONT BEARING VIBRATION INCREASED BEYOND ALARM VALUE (35 MICRONS, 0-PK). DURING THIS PERIOD, NO INCREASE IN SHAFT VIBRATION WAS OBSERVED
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

12. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
INTREPRETATION OF RESULTS AFTER INSITU BALANCING
AS HP FRONT BEARING PEDESTAL VIBRATION INCREASED, EVEN WHEN HP FRONT SHAFT VIBRATION WAS CONSTANT, INDICATED THAT THE CAUSE OF HIGH BEARING PEDESTAL VIBRATION WAS SOME FACTORS APART FROM UNBALANCE OF THE SHAFT
ANALYSIS DONE
BASED UPON THE VIBRATION BEHAVIOUR OF BEARING PEDESTAL AND SHAFT VIBRATION, IT WAS DECIDED TO SCAN FRONT BEARING PEDESTAL BY PORTABLE VIBRATION ANALYSER
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

13. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
RESULTS OF SCANNING OF FRONT PEDESTAL
VIBRATION ON LEFT AND RIGHT HAND SIDE OF FRONT BEARING PEDESTAL (NEAR HP CASING FRONT PALMS) IN THE VERTICAL DIRECTION WERE HAVING LARGE VARIATION
(LHS VIBRATION IS ABOUT 5 TIMES MORE THAN RHS VIBRATION)
HP CASING PALM VIBRATION AMPLITUDE IN VERTICAL DIRECTION ON LEFT AND RIGHT PALM WAS FOUND TO BE OF LOWER MAGNITUDE AND SAME
SCANNING INDICATED THAT THERE WAS NO PROBLEM WITH BASE PLATE, SECONDARY GROUT & FOUNDATION MATING SURFACES
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

14. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
HP CASING PAM (RIGHT HAND SIDE)
HP FRONT BEARING PEDESTAL
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

15. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
ANALYSIS
SCANNING DATA INDICATED THAT LOAD DISTRIBUTION BETWEEN PALMS OF HP CASING WAS NOT PROPER
THERE WAS GAP BETWEEN CASING PALM AND PEDESTAL ON LEFT HAND SIDE
ACTION TAKEN
0.15 MM SHIM WAS ADDED BELOW LEFT HAND SIDE PALM WHEREAS 0.1 MM SHIM WAS REMOVED FROM RIGHT HAND SIDE PALM FOR IMPROVING THE LOADING PATTERN OF HP CASING ON PEDESTAL
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

16. HIGH VIBRATION IN 500 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 500 MW TG SETS
RESULT OF CORRECTION IN SHIMS
VIBRATIONS ON BEARING PEDESTAL REDUCED FROM 35 MICRONS, 0-PK TO 15 MICRONS, 0-PK AND NO INCREASING TENDENCY WAS OBSERVED
HP FRONT SHAFT VIBRATION WAS FOUND TO BE REDUCED FROM 120 MICRONS, 0-PK TO 90 MICRONS, 0-PK AND BEARING VIBRATION SETTLED DOWN TO 10 MICRONS, 0-PK AT FULL LOAD
RATIO OF LEFT AND RIGHT HAND SIDE VIBRATION ON FRONT PEDESTAL IN VERTICAL DIRECTION CAME DOWN TO 2:1 FROM EARLIER VALUE OF 5:1
HENCE, UNBALANCE OF ROTOR SYSTEM & UNLOADING OF LEFT SIDE PALM WAS FOUND TO BE THE ROOT CAUSE OF THE HIGH HP FRONT SHAFT AND BEARING PEDESTAL VIBRATION
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

17. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
CONCLUSION
VIBRATION SCANNING IS A VERY IMPORTANT TOOL FOR DIAGNOSTICS PURPOSES
VIBRATION SCANNING SHOULD BE USED AS FREQUENTLY AS POSSIBLE
IT HELPS IN RULING OUT OR PIN POINTING CERTAIN DEFECTS
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

18. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN
210 MW TG SETS
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

19. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
BACKGROUND
MACHINE IS OF KWU DESIGN STEAM TURBINE COUPLED WITH LMW GENERATOR (LP REAR BEARING AND GENERATOR FRONT BEARING IS LOCATED IN COMMON PEDESTAL)
VIBRATION BEHAVIOUR WAS FOUND TO BE NORMAL DURING FIRST COMMISSIONING ON ALL BEARINGS AND LATER ON VIBRATION ON BEARING NO. 4 / 5 PEDESTAL DETERIORATED GRADUALLY BEYOND ALARM LEVELS (35 MICRONS, 0-PK)
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

20. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
PROBLEM
HIGH LP REAR BEARING VIBRATION
HIGH GENERATOR FRONT BEARING VIBRATION
OBSERVATIONS
FREQUENCY ANALYSIS CARRIED OUT WHICH INDICATED
PREDOMINANT 1-X VIBRATION COMPONENT FOR BOTH LP REAR AND GENERATOR FRONT VERTICAL AND AXIAL VIBRATION
VERTICAL VIBRATION AT LP REAR AND GENERATOR FRONT BEARING WAS OF THE ORDER OF 100 MICRONS, PK-PK
AXIAL VIBRATION WAS ABOUT 200 MICRONS, PK-PK FOR BOTH LP REAR BEARING AND GENERATOR FRONT BEARING
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

21. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
ANALYSIS
BASED ON VIBRATION SYMPTOMS, FOLLOWING CHECKS WERE SUGGESTED IN PLANNED OVERHAUL
LP / GENERATOR ALIGNMENT
BEARING ASSEMBLY CHECKS
RESULT OF ABOVE WORKS
AFTER CARRYING OUT THE ABOVE MENTIONED CHECKS & CORRECTIONS DURING PLANNED OVERHAUL, VIBRATION LEVEL DID NOT IMPROVE
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

22. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
ACTION TAKEN
FOLLOWING WORKS WERE CARRIED OUT
VIBRATION ANALYSIS
SCANNING OF LP REAR BEARING PEDESTAL AND ITS SECONDARY GROUT AND BASE PLATE AREA
OBSERVATIONS / ANALYSIS
FREQUENCY BEHAVIOUR OF BEARING VIBRATION FOUND SIMILAR TO EARLIER OBSERVATION
WIDE DIFFERENCE IN PHASE ANGLE IN VERTICAL DIRECTION ACROSS BASE PLATE OF LP REAR PEDESTAL AND SECONDARY GROUTING WHICH INDICATED THAT VERTICAL LOAD TRANSFER FROM BEARING TO FOUNDATION IS NOT AS EXPECTED
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

23. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
SCANNING OF PEDESTAL 3 2 1 7 8 9 6 5 4
GENERATOR SIDE B
BASE PLATE D
LEFT 12 C 15 11 14 A
RIGHT 21 10 13 20 18 17 19 16
SECONDARY GROUT
TURBINE SIDE
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

24. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
ACTION PLAN SUGGESTED
REGROUTING OF LP REAR PEDESTAL
REPLACEMENT OF FOUNDATION BOLTS OF LP REAR PEDESTAL AND PROPER MATCHING OF ANCHOR PLATES
IN-SITU BALANCING OF GENERATOR ROTOR TO REDUCE EXCITATION FORCES TO MINIMUM
DUE TO TIME CONSTRAINT AND POWER REQUIREMENT,
FOLLOWING WORKS CARRIED OUT
EPOXY GROUTING (PRESSURE GROUTING) OF LP REAR PEDESTAL
RESTRETCHING OF FOUNDATION BOLTS OF LP REAR PEDESTAL
LP / GENERATOR REALIGNMENT
BEARING INSPECTION
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

25. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
RESULT OF ABOVE WORKS
AFTER CARRING OUT THE ABOVE MENTIONED CHECKS DURING NEXT OVERHAUL
VIBRATION LEVEL FOUND REDUCED TO 25 MICRONS, 0-PK ON BEARING NO. 4 / 5 PEDESTAL
PHASE DIFFERENCE WAS FOUND TO BE MINIMUM BETWEEN BEARING PEDESTAL BASE PLATE AND SECONDARY GROUTING
BUT AFTER FEW DAYS OF OPERATION,
VIBRATION LEVEL STARTED INCREASING GRADUALLY AND TOUCHED ALARM VALUE OF 35 MICRONS, 0-PK
PHASE ANGLE DIFFERENCE WAS ALSO FOUND TO BE INCREASING BETWEEN BASE PLATE AND SECONDARY GROUTING
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

26. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
ANALYSIS
EPOXY GROUTING WAS INSUFFICIENT TO CURE THE VIBRATION PROBLEM ON PERMANENT BASIS
AT THIS POINT OF TIME, CIVIL EXPERT ALSO CONDUCTED STUDIES ON FOUNDATION WHICH CONFIRMED THE BAD CONDITION OF SECONDARY GROUT
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

27. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
ACTION PLAN SUGGESTED:
ONCE AGAIN THE PREVIOUS ACTION PLAN WAS SUGGESTED, THAT IS,
REMOVAL OF LP REAR BEARING PEDESTAL AFTER BREAKING SECONDARY GROUTING COMPLETELY
REPLACEMENT OF FOUNDATION BOLTS
IN-SITU BALACNING OF GENERATOR ROTOR
DISMANTLING OBSERVATION
DURING REMOVAL OF LP REAR PEDESTAL, SECONDARY GROUT MATERIAL WAS FOUND IN PIECES
OIL SEEPAGE WAS OBSERVED UNDER PEDESTAL
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

28. HIGH VIBRATION IN 210 MW TG SETS
A.K.SINHA, DGM (TURBINE)
HIGH VIBRATION IN 210 MW TG SETS
RESULT OF ABOVE WORKS
AFTER THE ABOVE MENTIONED WORKS CARRIED OUT (INCLUDING IN-SITU BALANCING OF GENERATOR ROTOR) IN THE NEXT PLANNED OVERHAUL, VIBRATION LEVEL OF LP REAR AND GENERATOR FRONT IMPROVED IN BOTH VERTICAL AND AXIAL DIRECTION
MACHINE IS RUNNING SATISFACTORILY SINCE THEN
HENCE, LOOSENESS / VOID BETWEEN LP REAR PEDESTAL AND SECONDARY GROUTING WAS FOUND TO BE THE ROOT CAUSE OF HIGH LP REAR PEDESTAL AND GENERATOR FRONT VIBRATION
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

29. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
CONCLUSION
HISTORY OF THE PROBLEM SHOULD BE GIVEN DUE WEIGHTAGE FOR ANALYSING THE PROBLEM
ATTENTION SHOULD BE PAID TO INTERFACE AREAS BETWEEN MACHINE AND SUPPORTING SYSTEM / STRUCTURE IN ADDITION TO MAIN MACHINE
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

30. TIPS FOR BETTER DIAGNOSTICS
A.K.SINHA, DGM (TURBINE)
TIPS FOR BETTER DIAGNOSTICS
HISTORY OF MACHINE WITH RESPECT TO ITS DYNAMIC BEHAVIOUR SHOULD BE STUDIED
REGULAR VIBRATION READING ON BEARING PEDESTAL AT PRESCRIBED LOCATIONS SHOULD BE TAKEN FOR ASSESSING THE TREND OF VIBRATION BEHAVIOUR ACCURATELY
SHAFT VIBRATION IN TWO ORTHOGONAL DIRECTIONS SHOULD BE MEASURED FOR ORBIT ANALYSIS
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

31. RECOMMENDED LOCATIONS OF VIBRATION MEASUREMENTS ON BEARINGS AS PER ISO
A.K.SINHA, DGM (TURBINE)
RECOMMENDED LOCATIONS OF VIBRATION MEASUREMENTS ON BEARINGS AS PER ISO
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

32. A.K.SINHA, DGM (TURBINE)
RECOMMENDED LOCATIONS OF SHAFT VIBRATION MEASUREMENTS AS PER ISO
Measuring Amplifier
Measuring Amplifier
PROXIMITY PICK-UP
45O
45O
VERTICAL L R R OR L
SHAFT
SHAFT
HORIZONTAL
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

33. TIPS FOR BETTER DIAGNOSTICS
A.K.SINHA, DGM (TURBINE)
TIPS FOR BETTER DIAGNOSTICS
EVERY UNIT SHOULD HAVE KEY PHASOR ARRANGEMENT FOR VIBRATION ANALYSIS.
SCANNING OF VIBRATION PRONE AREAS INCLUDING SYSTEM / FOUNDATION AROUND THE PROBLEMATIC AREA SHOULD BE CONDUCTED
DEVIATION IN OPERATING PARAMETERS SHOULD BE RECORDED AND ANALYSED FOR THEIR EFFECT ON VIBRATION BEHAVIOUR
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

34. TIPS FOR BETTER DIAGNOSTICS
A.K.SINHA, DGM (TURBINE)
TIPS FOR BETTER DIAGNOSTICS
RUN UP & RUN DOWN VIBRATION BEHAVIOUR SHOULD BE RECORDED FOR ALL BEARINGS AND SHAFT POSITIONS FOR REFERENCE WHICH CAN BE USED DURING TROUBLESHOOTING
PRE-OUTAGE SURVEY SHOULD BE CONDUCTED PRIOR TO OVERHAUL FOR BETTER PLANNING OF ADDITIONAL ACTIVITIES / SPARES, IF REQUIRED
RECORD OF PREVIOUS BALANCING AT SITE SHOULD BE MAINTAINED FOR REFERENCE PURPOSES
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

35. TIPS FOR BETTER DIAGNOSTICS
A.K.SINHA, DGM (TURBINE)
TIPS FOR BETTER DIAGNOSTICS
LAST BUT NOT THE LEAST, DURING TROUBLESHOOTING, EVERY FEEDBACK / OBSERVATION NEEDS TO BE CONFIRMED. IF EVERYTHING IS ALRIGHT, VIBRATION PROBLEM WOULD NOT HAVE BEEN THERE. SO VERIFY EACH & EVERY POSSIBILITY AND CONFIRM FROM WRITTEN DOCUMENTS
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA

36. BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA
A.K.SINHA, DGM (TURBINE)
Thank you
BHEL, POWER SECTOR – TECHNICAL SERVICES (HQ), NOIDA