Rewind and Core Restack of AEP Conesville #5 Generator

2004 ◽  
Author(s):  
J. Timperley ◽  
J. Michalec ◽  
W. Moore ◽  
H. Moudy ◽  
J. Hutt
Keyword(s):  
Cost Effective ◽  
Original Design ◽  
Specific Design ◽  
Stator Core ◽  
Cause Analysis ◽  
Root Cause ◽  
The Core ◽  
Phase Lead ◽  
The Past ◽  
Core Damage

This paper presents an overview of the design and field installation events involved in rewinding and restacking AEP’s Conesville #5 generator. This style of generator, commonly known as a “double tube stack” machine, has been susceptible in the past to stator end winding vibration, stator coil and core deterioration, and phase lead problems. Following tests and inspections, AEP decided to rewind this generator in anticipation of the consequences of these problems. Successful pro-active maintenance, which included a complete stator rewind and stator core restack, prevented a costly forced outage. Root cause analysis of the coil failures are described, as well as details of the core laminations problems. Specific design enhancements over and above the original design will be discussed. In addition, details of the existing core damage will be discussed, as well as procedures used for core restacking. Fiber optic monitoring instruments were installed on the coil ends and the phase leads after the new coil installation was complete. Results of these initial readings will be shared. Successful startup and continued operation of this unit demonstrates that refurbishment of these large generators with inner gas cooled technology is reliable and cost-effective over other alternatives, such as conversion to water cooled technology.

Value and Cost Effectiveness of Conducting a Root Cause Analysis

2012 ◽  
Author(s):  
André-Michel Ferrari ◽  
Brad Jones
Keyword(s):  
Cost Effectiveness ◽  
Cost Effective ◽  
Root Cause Analysis ◽  
Cause Analysis ◽  
Team Members ◽  
Root Cause ◽  
Effective Manner ◽  
Knowledge Enhancement ◽  
Primary Driver ◽  
The Cost

The formal Root Cause Analysis (RCA) process consists of a structured approach to identifying the underlying factors that result in the unwanted outcomes of one or more typically negative past events (chronic or sporadic). The process helps to identify what systems or behaviors need to be modified to prevent recurrence of similar outcomes. The fundamental driver of the RCA is to eliminate the causes that lead to the unwanted event rather than addressing the symptoms of the event. This generally leads to multiple corrective actions rather than a single solution. Based on various root causes analyses conducted by a department in Enbridge Pipelines since 2006, various benefits provided by RCA exercises are highlighted in this paper. The findings were mainly derived from completed RCAs as well as RCA team member surveys. Firstly, the cost effectiveness of the RCA process was identified as a primary driver for this exercise. For example, one RCA involving a multidisciplinary team of 8 members, costing approximately $35,000, led to $1M in recommended solutions generating $16M in potential savings. In other words, each of the 350 hours spent on the RCA produced $8,571 in savings underlining the value creation to the company. Secondly, the RCA process combined with the power of the team reflection led to the identification of new issues which were causing other revenue losses to the company. Because these issues were not part of the defined scope of the original RCA, their root causes were not be immediately assessed but nevertheless their impact could easily be quantified and forwarded to Management for review. The third benefit highlighted by RCAs is more of an educational benefit to team members and subsequently the organization. Through cross functional examination of the issues and events, the team members became aware and educated on issues that would not have otherwise been apparent. Additionally, by working through the RCA methodology, the team members enhanced their problem solving abilities which benefit their everyday work. In conclusion, other than identifying techniques to preclude unwanted outcomes and providing cost saving opportunities in a very cost effective manner, RCAs can be considered as an effective knowledge enhancement tool for an organization.

Axial Compressor Blade Failure, Design Modification, and its Validation

2015 ◽  
Author(s):  
C. J. Hulme ◽  
S. W. Fiebiger ◽  
J. Szwedowicz
Keyword(s):  
Axial Compressor ◽  
Root Cause Analysis ◽  
Compressor Blade ◽  
Design Tool ◽  
Original Design ◽  
Successful Operation ◽  
Damage Mechanisms ◽  
Design Modification ◽  
Cause Analysis ◽  
Root Cause

Utilising a comprehensive design tool suite and in-house knowledge, the root cause analysis of High Cycle Fatigue (HCF) failures on the first stage compressor blade in a gas turbine (GT) engine is presented in this paper. Based on the experience gained from the root cause analysis more reliable lifetime prediction for compressor blade design is possible. Tip timing measurements of blades in service have been evaluated to obtain valuable information about the real vibratory stress levels of the first stage compressor blades, to validate design methods, and to identify the failure mechanism. Metallurgical evaluation and testing of the failed parts were also used as part of the investigation. During the failure investigations the impacts of important damage mechanisms, not identified in the original design process, were determined. These damage mechanisms included, water droplet erosion of blades due to impingement on highly stressed regions of airfoil, mistuning within manufactured blade sets, and a very strong transient aerodynamic loading. Considering the damage mechanisms, improved design methodologies have been used to design robust compressor blade sets. These have been validated in successful engine tests. Subsequent continued successful operation of new blade designs has been recorded in engines during an extended validation period.

Root Cause Analysis of a Leak Off Tube of the Primary Loop in a CANDU 6 Unit

2017 ◽  
Author(s):  
Liang Zhao ◽  
Kunjie Luo
Keyword(s):  
Fracture Morphology ◽  
Composition Analysis ◽  
Collection System ◽  
Original Design ◽  
Cause Analysis ◽  
Maintenance Strategies ◽  
Corrosion Fatigue Crack ◽  
Root Cause ◽  
Design Requirements ◽  
Wall Surface Temperature

Chemical composition analysis, microstructure analysis, macro and micro fracture morphology analysis were conducted on a cracked leak off tube in primary heat transport and heavy water collection system of a CANDU6 unit. The results show that the material conforms to the original design requirements. The leaked fluid vaporized at the penetration and stress corrosion crack initiated because of cl-concentration. The leaked fluid drains periodically and lead the wall surface temperature periodically changes. The SCC crack transformed to corrosion fatigue crack and the tube finally fractured. In order to prevent the similar tubes crack again, preventive maintenance strategies were given in this paper.

scholarly journals Real-Time Bedside Root Cause Analysis (RCA) as a Catalyst for Clostridioides difficile Reduction

2020 ◽  
Vol 41 (S1) ◽  
pp. s366-s367
Author(s):  
Hannah Newman ◽  
Linda Kirschenbaum ◽  
Irene Macyk ◽  
Daniel Baker ◽  
Janet C Haas
Keyword(s):  
Patient Care ◽  
Real Time ◽  
Infection Risk ◽  
Frontline Staff ◽  
Cause Analysis ◽  
Clinical Leadership ◽  
Staff Members ◽  
Root Cause ◽  
The Past ◽  
Clostridioides Difficile

Background:C. difficile infection has been a significant cause of morbidity and mortality over the past decade. Our hospital had rates of hospital-onset, laboratory-identified, C. difficile infection (HO-CDI) that were significantly higher than our state and national benchmarks. HO-CDI is defined as a test positive for C. difficile occurring on or after day 4 of hospitalization, regardless of the presence of symptoms. New leadership at the hospital sought a creative way to engage staff in finding solutions to our high rates of HO-CDI. Objective: The purpose of this intervention was to engage frontline staff in reporting and solving patient care situations that may increase infection risk to decrease HO-CDI rates. Methods: Starting in July 2015, real-time bedside RCAs were performed weekly for any HO-CDI on the unit to which the infection was attributed and on any unit from which the patient had been recently transferred. Top clinical leadership of the hospital, and all services and departments, physicians, nurses, and others involved with the patient’s care were expected to attend and identify factors that may have contributed to the infection. The findings were documented, and changes to care were made based on the findings. The rate of incident hospital onset HO-CDI per 10,000 patient days was used to measure outcome because standardized infection ratios for the period before 2016 were not available. Results: Staff members suggested 6 specific actions that were undertaken to decrease HO-CDI risk (Table 1). The HO-CDI rate during the preintervention period (2012–2014) was 6.85 per 10,000 patient days (275 cases). In the postintervention period (2016–2018) the HO-CDI rate was 3.13 per 10,000 patient days (101 cases). There was a 54% reduction in the HO-CDI rate in the postintervention period (P < .001). Conclusions: The multidisciplinary bedside RCA process resulted in staff providing recommendations for actions to reduce HO-CDI risk. Implementation of staff suggestions resulted in a sustained, significant decrease in HO-CDI.Funding: NoneDisclosures: None

Fretting Fatigue Modeling and Repair Evaluation for Generator Rotors

2003 ◽  
Author(s):  
Srikanth Akkaram ◽  
Mandar Chati ◽  
Sairam Sundaram ◽  
Gary Barnes
Keyword(s):  
Fatigue Testing ◽  
Failure Mechanisms ◽  
Element Model ◽  
Fretting Fatigue ◽  
Field Observations ◽  
Cause Analysis ◽  
Operating Modes ◽  
Root Cause ◽  
The Past ◽  
Rotor Tooth

Generator Rotor Tooth Cracks have been recently observed on some long service generator rotors. The purpose of this paper is to document the root cause analysis as well as a repair methodology that was developed in support of one of these cracked units. The paper discusses the development of a finite element model to understand the operating modes and failure mechanisms that caused the initiation of these cracks. The results of the analysis agreed very well with field observations on cracked units and with some limited repair options that have been successfully used in the past. An experimental fretting fatigue testing program is currently underway to substantiate and extend the results reported in this paper.

Root Cause analysis of SG tube ODSCC indications within the tube sheets of NPP biblis unit A

2011 ◽  
pp. 78-86
Author(s):  
R. Kilian ◽  
J. Beck ◽  
H. Lang ◽  
V. Schneider ◽  
T. Schönherr ◽  
...  
Keyword(s):  
Root Cause Analysis ◽  
Cause Analysis ◽  
Root Cause

Soziale Disziplinierung im flexiblen Kapitalismus

2004 ◽  
Vol 34 (136) ◽  
pp. 339-356
Author(s):  
Tobias Wölfle ◽  
Oliver Schöller
Keyword(s):  
Social Welfare ◽  
Second Step ◽  
Social Rights ◽  
Federal Law ◽  
Capitalist Development ◽  
The Core ◽  
The Past ◽  
The Impact ◽  
Municipal Level

Under the term “Hilfe zur Arbeit” (aid for work) the federal law of social welfare subsumes all kinds of labour disciplining instruments. First, the paper shows the historical connection of welfare and labour disciplining mechanisms in the context of different periods within capitalist development. In a second step, against the background of historical experiences, we will analyse the trends of “Hilfe zur Arbeit” during the past two decades. It will be shown that by the rise of unemployment, the impact of labour disciplining aspects of “Hilfe zur Arbeit” has increased both on the federal and on the municipal level. For this reason the leverage of the liberal paradigm would take place even in the core of social rights.

Regulatory and sustainability initiatives lead to improved polyaminopolyamide epichlorohydrin (PAE) wet-strength resins and paper products

TAPPI Journal ◽  
2018 ◽  
Vol 17 (09) ◽  
pp. 519-532 ◽  
Author(s):  
Mark Crisp ◽  
Richard Riehle
Keyword(s):  
Health And Safety ◽  
Cost Effective ◽  
Worker Safety ◽  
Regulatory Requirements ◽  
Wet Strength ◽  
The Past ◽  
Consumer Safety ◽  
Federal Institute ◽  
Sustainability Initiatives ◽  
The Impact

Polyaminopolyamide-epichlorohydrin (PAE) resins are the predominant commercial products used to manufacture wet-strengthened paper products for grades requiring wet-strength permanence. Since their development in the late 1950s, the first generation (G1) resins have proven to be one of the most cost-effective technologies available to provide wet strength to paper. Throughout the past three decades, regulatory directives and sustainability initiatives from various organizations have driven the development of cleaner and safer PAE resins and paper products. Early efforts in this area focused on improving worker safety and reducing the impact of PAE resins on the environment. These efforts led to the development of resins containing significantly reduced levels of 1,3-dichloro-2-propanol (1,3-DCP) and 3-monochloropropane-1,2-diol (3-MCPD), potentially carcinogenic byproducts formed during the manufacturing process of PAE resins. As the levels of these byproducts decreased, the environmental, health, and safety (EH&S) profile of PAE resins and paper products improved. Recent initiatives from major retailers are focusing on product ingredient transparency and quality, thus encouraging the development of safer product formulations while maintaining performance. PAE resin research over the past 20 years has been directed toward regulatory requirements to improve consumer safety and minimize exposure to potentially carcinogenic materials found in various paper products. One of the best known regulatory requirements is the recommendations of the German Federal Institute for Risk Assessment (BfR), which defines the levels of 1,3-DCP and 3-MCPD that can be extracted by water from various food contact grades of paper. These criteria led to the development of third generation (G3) products that contain very low levels of 1,3-DCP (typically <10 parts per million in the as-received/delivered resin). This paper outlines the PAE resin chemical contributors to adsorbable organic halogens and 3-MCPD in paper and provides recommendations for the use of each PAE resin product generation (G1, G1.5, G2, G2.5, and G3).

Adaptations of Time Travel Narratives in Japanese Multimedia: Nurturing Eudaimonia across Time and Space

2014 ◽  
Vol 7 (2) ◽  
pp. 136-151 ◽  
Author(s):  
Sung-Ae Lee
Keyword(s):  
Travel Narratives ◽  
Time Travel ◽  
Cultural Knowledge ◽  
Human Beings ◽  
The Core ◽  
The Past ◽  
Life Styles ◽  
Concern For Others ◽  
The Future ◽  
Live Action

To displace a character in time is to depict a character who becomes acutely conscious of his or her status as other, as she or he strives to comprehend and interact with a culture whose mentality is both familiar and different in obvious and subtle ways. Two main types of time travel pose a philosophical distinction between visiting the past with knowledge of the future and trying to inhabit the future with past cultural knowledge, but in either case the unpredictable impact a time traveller may have on another society is always a prominent theme. At the core of Japanese time travel narratives is a contrast between self-interested and eudaimonic life styles as these are reflected by the time traveller's activities. Eudaimonia is a ‘flourishing life’, a life focused on what is valuable for human beings and the grounding of that value in altruistic concern for others. In a study of multimodal narratives belonging to two sets – adaptations of Tsutsui Yasutaka's young adult novella The Girl Who Leapt Through Time and Yamazaki Mari's manga series Thermae Romae – this article examines how time travel narratives in anime and live action film affirm that eudaimonic living is always a core value to be nurtured.

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