Assessment of Hydraulic Network Models in Predicting Reverse Flows in OD Cooled Disc Type Transformer Windings

© 2013 IEEE. Predicting liquid flow distribution in the winding is crucial for transformer thermal design and hydraulic network models are usually used to guarantee reasonable liquid flow distribution. This paper is a continuation of the research effort in using computational fluid dynamics (CFD) to calibrate and improve the network modelling approach. The possibility is assessed of hydraulic network models in predicting the occurrence of reverse flows in pump-driven oil directed (OD) cooling modes. CFD modelling shows that the occurrence of reverse flows requires both high Reynolds number at the winding pass inlet and the 'real' pass inlet velocity profile. To reflect the effect of pass inlet velocity profile on flow distribution, a winding pass is added beneath dividing and merging junctions in deriving minor pressure loss correlations. In addition, hybrid minor loss correlations are used to incorporate the effect of pass inlet velocity profile and to mitigate the inaccuracy of minor pressure loss segregation introduced by the inclusion of a winding pass beneath the junctions. Even with the above mentioned improvements, a conventional network model with one node for each junction still cannot predict reverse flows because of its architecture limit, hence a 3-node junction network model is then proposed. It is demonstrated that the newly developed 3-node junction hydraulic network model can predict the occurrence of reverse flows in OD cooled disc-type transformer windings

MOD-0A 200 kW wind turbine generator design and analysis report

The design, analysis, and initial performance of the MOD-OA 200 kW wind turbine generator at Clayton, NM is documented. The MOD-OA was designed and built to obtain operation and performance data and experience in utility environments. The project requirements, approach, system description, design requirements, design, analysis, system tests, installation, safety considerations, failure modes and effects analysis, data acquisition, and initial performance for the wind turbine are discussed. The design and analysis of the rotor, drive train, nacelle equipment, yaw drive mechanism and brake, tower, foundation, electricl system, and control systems are presented. The rotor includes the blades, hub, and pitch change mechanism. The drive train includes the low speed shaft, speed increaser, high speed shaft, and rotor brake. The electrical system includes the generator, switchgear, transformer, and utility connection. The control systems are the blade pitch, yaw, and generator control, and the safety system. Manual, automatic, and remote control are discussed. Systems analyses on dynamic loads and fatigue are presented

Cumulative index to NASA Tech Briefs, 1970-1975

Tech briefs of technology derived from the research and development activities of the National Aeronautics and Space Administration are presented. Abstracts and indexes of subject, personal author, originating center, and tech brief number for the 1970-1975 tech briefs are presented

Proceedings of the 10th international conference on energy efficiency in motor driven systems (EEMODS' 2017)

The 10th International Conference on Energy Efficiency in Motor Driven Systems (EEMODS'17) was be held in Rome (Italy) on 6-8 September, 2017. The EEMODS conferences have been very successful in attracting distinguished and international presenters and attendees. The wide variety of stakeholders has included professionals involved in manufacturing, marketing, and promotion of energy efficient motors and motor driven systems and representatives from research labs, academia, and public policy. EEMODS’15 provided a forum to discuss and debate the latest developments in the impacts of electrical motor systems (advanced motors and drives, compressors, pumps, and fans) on energy and the environment, the policies and programmes adopted and planned, and the technical and commercial advances made in the dissemination and penetration of energy-efficient motor systems. In addition EEMODS covered also energy management in organizations, international harmonization of test method and financing of energy efficiency in motor systems. The Book of Proceedings contains the peer reviewed paper that have been presented at the conference.JRC.C.2-Energy Efficiency and Renewable

Hughes electrical and electronic technology

10th edition, 200

Index to NASA Tech Briefs, 1972

Abstracts of 1972 NASA Tech Briefs are presented. Four indexes are included: subject, personal author, originating center, and Tech Brief number