This paper describes the technologies and trends of demands of induction heating and arc heating in which Fuji Electric has achieved excellent developments leading the trade. The company has supplied about 1,200 induction furnaces since the first supply in 1964, and now is mainly manufacturing high-frequency induction furnaces. The supply of induction heating equipment, such as billet heaters, edge heaters, and sheet induction heater, has exceeded 200. Furnace transformers for arc heating reached 414 units, 7,125 MVA starting from 1929, and a world's largest 130-t DC arc furnace was manufactured in 1989.

Automatic pouring furnaces have made progress while used in cast iron foundries for automobile parts; also, copper alloy foundries have recently become eager to introduce them. In the automatic pouring of copper alloy, the uniformity of molten-metal temperature and prevention of oxidation are basic requirements for the stable quality of products. Fuji electric has completed a melting and automatic pouring system satisfying them enough. This paper gives an outline of the system.

Cast iron melting has mostly used cupolas and crucible type induction furnaces. Fuji Electric, in cooperation with Chubu Electric Power Co., Inc., has developed an automatic melting system to promote modernization of foundries, that makes use of night power for automatic melting and can apply to channel-type induction furnaces in which Fuji has a record of about 120 supplies. Its own new technologies, such as continuous measurement of molten-metal temperature, automatic protectors for molten-metal leakage, and automatic system control equipment developed for the system, aims to improve the production pattern in foundries. This paper outlines the system and its application.

The application of induction heating technology to steel sheets has ranged up to comparatively high temperatures (not exceeding 600℃).
This paper introduces the characteristic curve of saturated magnetic density to temperature at 50 Hz calculated from experiment data concerning steel sheet magnetic characteristics of steel sheets at temperatures currently used (300℃ and above).

Fuji Electric has supplied about 120 forging billet heaters for ten years since their manufacture started. The high-frequency power supplies of billet heaters usually used a thyristor type; however, many of them have recently used a compact, highefficiency transistor-inverter type because of semiconductor power device development. The sales record of the new type heaters has rapidly increased these two years mainly for small- and medium-scale customers. This paper introduces a transistor-inverter-type billet heater F180H/F300.

In 1978, Fuji Electric developed its own induction-type die heater that heated a die and a ring separated mainly aiming at rapid heating. Recently, it has developed a new induction-type die heater which can rapidly heat a die and a ring not separated and also can maintain and equalize temperature in the state they are.
This paper describes the purpose of die heating, the conventional heating method, an outline of the new die heater, and trends of die heating.

The success of Japan's first DC arc furnace in 1988 and the satisfactory operation of world's largest 130-t DC arc furnace in 1989 are spotlighted in expectation of large improvement in productivity. While large furnaces are constructed in succession, Fuji's third system is going to be put into trial operation. Though DC arc furnaces, when compared with AC ones, have the advantage of superiority in electrode consumption and electric power consumption and small flicker disturbance to the power supply system, their electric equipment and instrumentation systems are considerably complicated. This paper introduces an outline of the system and operation records of network disturbance.

Direct conduction heating is a method that an electric current is directly applied to a material to be heated and produces Joule's heat. The direct conduction heating power source formerly used a M-G set, IVR, Grebos phase balance circuit, or APR. Using a single-phase GTO inverter of 3-phase balance load and low-order harmonics, power sources up to about 10,000 kVA can be manufactured. Example of the reflow section of a tin-plating line and the heating of forging tool steel rods are introduced. The calculating method for a power supply capacity, control systems, and non-unifomity in heating in the reflow section are examined, citing the latest examples.

Cogeneration is a system to get electricity and heat from a fuel source at the same time, and the overall efficiency of 70 to 80%, much higher than conventional generating systems, can be expected. Systems reusing waste heat or by-product fuel were introduced long ago; recently, they have spread wide in the nonindustrial field because of the establishment of labor saving and the expansion of heat demands. This paper describes the present status conditions for spread, Fuji Electric's attitude and forecast.

Cogeneration systems will be widely used for industrial and nonindustrial use as an effective means of using energy efficiently because a high rate of energy utilization is obtainable.
This paper describes their system configurations, operation forms, system interconnection (technical conditions for cogeneration system interconnection), and formalities to the authorities concerned in introducing cogeneration systems.

Cogeneration supervision and control requires a wide-ranging system structured to cope with not only cogeneration equipment but also work process control and substation supervision and control.
This paper introduces supervisory control TOMFINE series, transistor chopper HIREX-85 series, and digital protective relays which compose integrated operation control systems of cogeneration equipment.

Fuji Electric has developed a packaged cogeneration system (FCGP system) using diesel engines of output 260-450 kW. This system, operated interconnecting an electric power company system, supplies electric power and hot water at the same time. With a stable hot-water load, overall energy utilization reaches 70 to 80%, The system is composed of a generator unit, a waste-heat retrieval unit, a generator panel, an interconnection protective relay panel, etc.; each unit is standardized.

Diesel-engine type cogeneration systems are mostly used in industries, and when classified according to heat recovery system forms, about half of them recovered by hot water and the rest, by steam and steam/hot water.
This paper describes the trend of industrial cogeneration demands and examples of supplied equipment.

Because nonindustrial-use cogeneration systems has been approved of interconnect ion with commercial power systems since the Ministry of International Trade and Industry issed "Guidelines on technical requirements of system interconnection," the number of their installations has rapidly increased to about 250 from 1984 to March, 1989.
Nonindustrial uses include hotels, hospitals, offices, leisure facilities, etc. This paper, citing examples of supplies for a hotel and a leisure facility, describes the introduction conditions and features of those systems.