Numerical analysis with a computer has carried great weight with progress in the technology of large capacity rotating machines. This paper describes recent applications to electro-magnetic field, power system, and coolant flow analyses, such as an analysis of electromagnetic exciting force in the armature slot portion of an AC variable-speed synchronous machine, a harmonic suppressor synchronous machine based on a new principle, and a distribution of cooling air pressure at the coil end portion of a rim ventilation machine.

Fuji Electric is promoting development of a new series of air-cooled turbine-generators greatly reduced in size, and has a plan to make a 120MVA machine on an experimental basis for the purpose of performance verification. In the case of large machines, experiments for development cannot be repeated. Simulation is effective to quickly check whether a development plan is suitable. This paper outlines the machine of experiment and the electromagnetic field, ventilation, vibration, and strength analyses carried out during development.

Owing to various technical developments, Fuji Electric can apply direct hydrogen-cooling to turbogenerators ranging to 1,000MVA. This paper describes advance in turbogenerator technology due to developments of analysis, material, and manufacturing technologies, focusing on the technologies applied to the 706MVA turbogenerator, the largest in unit capacity supplied by Fuji Electric.

In recent hydropower plants, technologies to reduce labor for maintenance have come into wide use. This paper describes recent cooling methods to reduce maintenance work, citing large capacity bulb turbine generators for Minokawai Power Plant, The Kansai Electric Power Co., Inc., Bailongtan Power Plant, China, and Chashma Power Plant, Pakistan as examples.

Recently, low speed, large capacity diesel generators have attracted attention because of the advantages of low fuel and maintenance costs. This paper describes the features of these generators, and also introduces the structure and system analyses carried out to manufacture the diesel generator ordered for Bahamas.

Because of the advantages of cost, on-site power supply, and environmental preservation, recent requirements for induction motors have been increase of capacity, reduction of starting current, and reduction of noise. Recently, Fuji Electric has manufactured large, squirrel-cage motors which strictly require low starting current and low noise. The characteristic test results of all the motors have satisfied the customer's requirements. This paper describes part of particular technologies used for designing the motors to reduce starting current and noise.

The bearing is a machine element regarded as a lifeline of rotating machines. Needless to say, it must be reliable. In addition, there are many requirements for improvement in performance and maintenance. This paper describes recent developments to meet these requirements, such as a PTFE (polytetrafluoroethylene) thrust bearing and its application used mainly for vertical hydraulic turbine generators, a great increase in the range of air cooling for the journal bearings of horizontal hydraulic turbine generators, and reduction in journal bearing loss for turbine generators.

Fuji Electric has applied its expanded totally vacuum-impregnated insulation system to large air-cooled turbogene-rators (260MVA) and indirectly hydrogen-cooled turbogene-rators (340MVA) of a newly developed series. This paper describes features of the totally vacuum-impregnated insulation system and application technology for large machines based on characteristic data.

Fuji Electric received an order for six 33 MW bulb turbine-generators for Bailongtan Power Plant, China, three units of which have already been put into commercial operation. The rest, three units, are being manufactured in China under Fuji Electric's design and manufacturing supervision. These turbine-generators are ranked high in size and capacity in Fuji Electric's record of manufacture. This paper outlines new technologies introduced into this plant.

Like gas-immersed transformers, cubicle gas-insulated switchgear (C-GIS) has rapidly come into use as substation equipment in harmony with the environment. Especially in factories and office buildings, there are growing demands for minimized space for electrical installations to maximize the business floor and front access to improve efficiency of maintenance work. Fuji Electric has developed new 84kV C-GIS to meet these market needs. This paper describes its constructional features and advantages.

Recently, high performance surge arresters with low residual voltage have begun to be applied to effectively grounded systems of 187kV or higher. Their standard have been established in Japan. Using fine-grain ZnO, Fuji Electric developed high performance ZnO elements with reference voltage per unit thickness exceeding 300V/mm, and then developed a new series of dead tank type surge arresters with these elements for 66kV to 275kV. This paper describes the features and improvements of the ZnO elements and the ratings, constructions, and some test results of the surge arresters.