Category Archives: D5-D5A Users

HRSG problem-solving 101: Don’t jump to conclusions

Sometimes you have to dig deeper into the detective work to identify not-so-obvious issues with your heat-recovery steam generators, HRST Inc’s Sam Shaw told the editors. Occasionally, captured DCS data are limited and more information is required to properly diagnose a nagging reliability issue. It’s easy to blame failures on an obvious root cause, but […]

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PAG acceptance grows with field experience

A CCJ special report by Consulting Editor Thomas F Armistead Powerplant operators, with good reason, are deeply reluctant to make changes in the basic components that their plants depend upon. There is simply too much at stake—system reliability, cost, lost revenue—to tinker with the operation of a plant that functions reasonably well 98% of the […]

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IEEE standards may not sufficiently address grounding issues in rotor, stator windings

Clyde V Maughan,, Maughan Generator Consultants There are two, unfortunately common, generator-winding failure modes that the IEEE standards overlook: the fracture of a rotor (field) conductor and the fracture of a stator conductor. This article describes these types of failures, discusses associated negative impacts of them, and recommends corrective actions. On rotor windings, IEEE Standard […]

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Engine vibration continues as a top concern of 501D5-D5A Users

The 501D5-D5A Users can be characterized as an intimate group, historically attracting about two-score attendees to its annual conferences and vendor fairs, fewer at the “mid-year” meetings in January. Most attendees have been repeat participants, several from far-away places like Korea and Indonesia, with the typical user knowing perhaps half of the owner/operators in the […]

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Hawaiian Electric advances the use of biodiesel as a gas-turbine fuel

State-mandated renewable portfolio standards are designed to shift the production of electricity from fossil fuels and nuclear power to wind, solar, biomass, and other green alternatives. The standards differ among the three-dozen states that have established RPSs with regard to the percentage of kilowatt-hours that must be produced from renewables by a given year. Hawaii […]

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Consider replication to verify metallurgy of buckets/blades after restoration heat treatment

To achieve the creep rupture life expected from a gas-turbine bucket/blade, and to ensure reasonable mechanical properties, the airfoil’s microstructure must have the ideal shape and distribution of its constituent phases, reminded John P Molloy, PE, of M&M Engineering Associates Inc, Leander, Tex, in a telephone call to CCJ’s offices. The primary beneficial phases of […]

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501D5-D5A users share major maintenance, repair experience

During the closed session at the recent 501D5-D5A Users Group meeting, discussion transitioned from engine vibration concerns to maintenance outages, experience with conventional and extended-life parts, repairs and coatings, etc—a cornucopia of subject matter. One attendee with a pending major inspection polled the group for experiences in using contractors for this work. Standard practice at […]

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