Browsing by Author "Peton, Nicolas"

Now showing 1 - 20 of 22
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    COMPRESSOR ROTOR CRACK CASE
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Popaleny, Peter; Blackwell, Joseph; Peton, Nicolas
    The case study describes rotor crack detection using vibration measurements, documented on real case of Induction Motor driven Compressor Unit. The study highlights the complexity of rotor crack diagnostics as the primary problem as it can be often masked by other existing machine malfunctions. In this case indication of the possible rotor crack, led to the Compressor bundle removal and rotor inspection. The rotor problem was confirmed, but not due to rotor crack but luckily only due to rotor thrust collar fit found to be worn and locating pin to be bent. Thrust collar had become eccentric (radial run out measured) causing a mass unbalance on the rotor in one direction, with similar symptoms as rotor crack. The gradual radial vibration increase on the compressor NDE bearing was observed on an export gas Compressor and the increase continued for several weeks. The vibrations were purely synchronous (1X) with a constant unidirectional phase angle. Following transient data comparisons, Lube Oil supply temperature checks, compressor feet / bearing housing vibration measurements and a NDE bearing inspection (no findings) the BN team diagnosed a rotor issue and insisted the compressor rotor was inspected. BN remotely witnessed the compressor inspection where it was discovered the thrust collar to rotor fit was worn and oversized, antirotating pin bended, causing the thrust collar to be eccentric resulting in an unbalance. This was proven on the high-speed balancing machine when the thrust collar eccentricity values could then be correlated with the rotor vibration response using an influence vector from installing a test weight at the thrust collar. Following the initial diagnosis and continued monitoring by the BN SSA team the machine was able to be safely operated for 6 months allowing for a replacement compressor bundle to be prepared and installed minimizing the operational and business impact.
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    CST05 - Fluid-Film Bearing Damage Detection Based on Vibration Data�
    (Turbomachinery Laboratory, [2019]) Yu, John; Peton, Nicolas
    This case occurred during startup after outage on a steam turbine generator. Vibration reached over full scale of 20 mil pp at generator drive end bearing and therefore tripped the unit. The major vibration component that tripped the unit was 0.5X sub-synchronous in a level of over 20 mil pp. 1X vibration excursions existed at constant speed before the trip event. Abnormal shaft centerline positions were observed. Shaft bow reached 10 mil pp at low speeds during coast-down. Bearing metal temperature reading was invalid. After an in-depth data review, diagnostic conclusions and recommendations were made, followed by correct actions. Inspection and findings confirmed bearing damage and rubs. If the vibration issue had simply be treated as rub, followed by re-start without opening the casing, further catastrophic damages would have occurred.
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    Detection of Broken Blade on Compressor
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Yu, John J.; Wang, Carl Feng; Yuan, Mingfeng; Peton, Nicolas; Guan, Xiaodong
    A sudden step change in vibration was observed on a 7400 rpm compressor with direct amplitude from 43 um pp to over 62 um pp (trip level) at NDE, thus tripping the unit Vibration reached over 120 um pp at 4000 rpm, compared to normally 20 um pp during coast down Vibration excursion was dominantly due to the 1 X component It was noticed that thrust probe gap readings started to fluctuate 6 months prior to the vibration trip A sudden change in unbalance was diagnosed, followed by an inspection It appeared that a balance pipe started to leak earlier, causing the axial thrust force to fluctuate, as indicated by fluctuating thrust gap It was possible that a piece of damaged fragments entered the gas flow and hit the 3 rd stage blade, thus breaking the blade to lead to a sudden change in unbalance.
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    ELECTROSTATIC  DISCHARGE� STG  COMPRESSOR
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Ponnanna, Bopanna Pudiyokada; Yu, John J.; Peton, Nicolas
    Electrostatic discharge (ESD) can cause catastrophic mechanical damage and lower the life span of an asset if not detected early and rectified. Continuous discharge of static electricity can cause micro pitting of bearing or shaft surface leading to material loss and eventual failure. This presentation outlines a success story where an ESD malfunction was detected on turbine compressor and subsequent diagnosis lead to prevention of asset failures. Changes in shaft centerline plots/DC gap trends and raises in bearing metal temperature were some of typical symptoms of ESD along with spiking pattern in orbit plots. These malfunctions and subsequent diagnosis to prevent failures and solution to resolve the issue are discussed in this presentation.
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    Gas Turbine With Rotor Crack Vibration Diagnostics
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Popaleny, Peter; Peton, Nicolas; Turbomachinery Symposium (46th : 2017)
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    High Vibration Due to Steam Turbine Deposits
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Yu, John; Zhou, Tony Wei; Lin, Haibo; Wang, Carl Feng; Peton, Nicolas; Turbomachinery Symposium (47th : 2018)
    This presentation provides a case study how to correctly deal with increased vibration on a steam turbine that drives a compressor. After the machine had not operated for a week, vibration level increased 5 times during its re-startup. The vibration was dominantly composed of 1X component. An in-depth review of vibration data as well as possible root-causes is demonstrated, to rule out some possible malfunctions. Balancing would be a quick fix to let this machine back in service, based on vibration data. What actions should we take, and is balancing would work in this case?
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    How to detect Electrostatic discharge (ESD) using proximity probes on rotating machines
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2020) Christin, Guillaume; Peton, Nicolas
    In this session, a brief introduction about electrostatic discharge phenomena will be done. Then three historical cases with Electrostatic Discharge (ESD) issue will be analyzed in order to explain how to detect Electrostatic Discharge using proximity probes. It will point out that the vibration behavior in case of ESD is not always the same.
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    Pelletizer Motor Bearing Damage Detection Based on Vibration Data
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Yu, John; Feng Wang, Carl; Wei Zhou, Tony; Lin, Haibo; Quan, Ju; Peton, Nicolas; Turbomachinery Symposium (46th : 2017)
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    Power Turbine Field And Shop Balance Experience
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Yu, John J.; Kirker, Michael; Peton, Nicolas
    A power turbine (PT) experienced a high 1X vibration issue. Balancing was attempted at two accessible planes on the shaft section. However, the unit could only operate with vibration below the alarm level in steady-state condition while experiencing over 10 mil pp and 1 in/sec pk in transient condition, which is not acceptable. A decision was made to remove the PT section for workshop balance. Indeed, excessive unbalance was measured on it at workshop and then reduced by 97%. Vibration level became very low afterwards at both conditions. From the current case, weight sensitivity or influence data was obtained with respect to the PT section plane. This makes it possible in the future to add correct weights at the PT section on-site without having to ship it for workshop balance. The lesson learned here is that obtaining balance influence data from available balance planes at all different running conditions is very important to see if it is feasible to reduce vibration to an acceptable level at all these conditions by using the available balance planes. If not, an alternative must be found, instead of vain attempts.
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    PT09 - Submersible pump condition monitoring using motor current signature analyses and vibration analyses comparison
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, [2019]) Popaleny, Peter; Peton, Nicolas; International Pump Users Symposium (35th : 2019); Turbomachinery Symposium (48th : 2019)
    The paper further shows the real case studies, analyses and findings on Submersible Pumps. The article contrasts the similarities vs. differences and advantages vs. disadvantages of both methods and may be of value for engineers to understand the pros. and cons. of each technology.Vibration Analysis are widely used to detect faults on Submersible Pumps. Vibration Analysis has been implemented for the detection of malfunction mainly of mechanical and process origin. The recommended practice on Submersible Pumps is to take the vibration measurement at each bearing of the Submersible Pump, what is challenging.Motor Current Signature Analysis is suitable alternative as the method does not require any sensor installation on the Submersible Pumps itself and the measurement is carried out remotely in the motor control unit. Improved MCSA, Model-Based Voltage and Current Analyses is using a mathematical model of the relationship between dynamic current and voltage to identify electrical, mechanical or process problems. MBVI is especially attractive for inaccessible driven equipment and well suited for the monitoring of Submersible Pumps. The paper shows the real case studies on Submersible Pumps, such as Sea Water Lift Pumps,Sea Water Vaporizer Pumps and submerged Cryogenic Pumps.
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    Pump Tut - WHY MACHINES FAIL TO FOLLOW TEXTBOOK STATED RULES, AS ILLUSTRATED BY SHAFT CRACK AND ROTOR SELF EXCITED VIBRATION CASES IN CRITICAL MACHINERY
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2020) Mialkowski, Piotr; Peton, Nicolas; Popaleny, Peter
    This tutorial demonstrates some aspects of rotating machinery diagnostics where there is an apparent difference between the actual response of a machine and its expected behavior for a certain type of malfunction as typically found in industry analyst training courses. This tutorial concentrates on two of the most devasting malfunctions: shaft cracks and fluid film instabilities. The seriousness of these two malfunctions demands the immediate attention by the analyst to quickly determine before the potential catastrophic and terminal results. The reason of selecting these two is because both are serious and potentially terminal problems. From another perspective these malfunctions are on opposite ends of the vibration based diagnostics path. The shaft crack grows slowly and is a forced vibration problem related to the condition of a single machine part (rotor), whereas fluid film induced instabilities are invariably an instantaneous phenomenon that causes self-excited vibrations of high enough to trip the machine. However, a common factor for both malfunctions is that a maintenance experts say these malfunctions are relatively rare phenomena. As a result, to identify faults correctly, diagnostic engineers must rely on analyst training courses and published case history literature, rather than on personal experience. For both malfunctions we start with a short presentation of the diagnostics methodology, as used in the service organization the authors are employed, followed by a discussion of the practical implementation of this methodology along with selected machinery case studies.
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    Resolving Cyclic Vibration on an Instrument Air Compressor
    (Turbomachinery Laboratories, Texas A&M Engineering Experiment Station, 2016) Sharma, Amit; Peton, Nicolas; Turbomachinery Symposium (45th : 2016)
    Instrument Air Compressors are considered critical equipment in the plants, supplying compressed air to the instrumentations in the field. This case study focuses on cyclic vibration phenomena observed in the 2nd and 3rd stages of an Instrument Air Compressor, part of an Integral Gear Compressor train driven by a motor. The machine train is equipped with an online vibration monitoring and protection system with online diagnosis software, which was used to diagnose the phenomena & forward path for the resolution.
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    Resolving Structural Vibration Issues On a Multi Stage Pump
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Peton, Nicolas; Ganesh, Sankar
    There are three multistage pumps supplied as part of a new project for transporting diesel from one location to another. Earlier, the transportation of diesel was carried out using trucks for this facility. The availability of these pumps are critical to ensure that the diesel transportation is smooth without the needing the truck services. The machine train is equipped with online vibration monitoring & protection system with online diagnostic software. During the commissioning, it was noticed that the pumps were not able to reach the maximum continuous speed of 50.7 Hz (Max rated speed is 53.8 Hz) and were tripping on high vibration at the pump casing. The operation of these pumps were limited with the speed restrictions using the Variable Frequency Drive (VFD) system. The data review from the online diagnostics system revealed that these pumps were tripping on high vibration due to the excitation of pump vane pass frequency (195 Hz), when the pump was reaching the speed of 39Hz. Further tests concluded that the pump casing natural frequency was matching with the vane pass frequency of 195 Hz. This case study is designed to outline how the high vibration issue was successfully diagnosed, the root cause for the high vibration defined and finally how the problem was mitigated using some of the structural analysis techniques (modal analysis, Operating Deflection Shape etc). Lessons learned are also discussed in view of the discovery methodology using expert system available on site, from the project point of view as well as from design point of view.
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    Resolving Structural Vibration Issues On a Water Flood Pump
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Drygin, Sergey; Leonov, Dmitry; Peton, Nicolas; International Pump Users Symposium (33rd : 2017)
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    Resolving Structural Vibration On a Pump
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2017) Ganesh, Sankar; Peton, Nicolas; International Pump Users Symposium (33rd : 2017)
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    Self excited torsional vibration in single shaft combined cycle turbine-generator train
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2020) Mialkowski, Piotr; Peton, Nicolas
    This case history describes the investigation of the source of unstable behavior of a newly commissioned single-shaft, combined cycle, power generator unit. The source was found to be nonlinear operation of the flexible coupling between the generator and steam turbine, causing self-excited parametric torsional oscillations, transferred into radial vibration, detectable in monitoring system.
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    SILO EXHAUST FAN – STRUCTUAL VIBRATION  ODS AND MA
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2022) Ponnanna, Bopanna Pudiyokada; Yu, John J.; Drygin, Sergey; Peton, Nicolas; Schluter, Steven
    This case study outlines how structural vibration was resolved using two different technologies and highlighting secondary issues that can arise due to continued vibration because of structural resonance. Continued high vibration due to structural resonance can induce fatigue in mechanical components and will cause them to fail. It is important to diagnose structural resonance very early to avoid catastrophic failures. Two different technologies which have their own advantages and disadvantages were used to diagnose the root cause of the structural issue and corrective actions were carried out to improve the structural vibration.
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    Steam Whip Phenomenon in Steam turbine
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2018) Peton, Nicolas; Drygin, Sergey
    This case study is designed to outline how the high vibration issue was successfully diagnosed, the root cause for the high vibration found and correction actions recommended. The source of mentioned high vibration - sub synchronous excitations is steam induced instability – steam whip, detected in HP/LP turbine seals, closer to Drive End bearing. This turbine was initially equipped by Antiswirl packages. It was confirmed that this system is installed or operated not properly, non-original spare parts were installed during last overhaul.
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    Structural Resonance on Aeroderivative Driven Propeller
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2023) Ponnanna, Bopanna; Yu, John J.; Peton, Nicolas; Mumford, Bill
    This presentation summarizes a case study involving high vibrations detected on the casing between the power turbine and clutch of a ship during sailing
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    Structural Resonance on Aeroderivative Driven Propeller
    (Turbomachinery Laboratory, Texas A&M Engineering Experiment Station, 2023) Ponnanna, Bopanna; Yu, John J.; Peton, Nicolas; Mumford, Bill
    This presentation summarizes a case study involving high vibrations detected on the casing between the power turbine and clutch of a ship during sailing