Thyristor Controlled, 4300-kW Power Supply System for a Mixed Melter Glass Furnace

An earlier paper described the use of high power thyristors in booster power supplies for glass melting. Since that time, the availability of even larger thyristors has allowed the economical design of larger power supply systems. This paper describes the design features of a 4.3-MW thyristor-controlled power-regulated glass melting power system. The system is installed on a 115-ton mixed melter furnace with bottom electrodes used in the production of opal borosilicate glass. It includes high-voltage switchgear, dual secondary power transformers, and water-cooled power cables along with the thyristor (SCR) equipment. Some information is also presented on electrode peripheral equipment, startup procedures, and a method of computing approximate circuit resistance for use in determining controller and transformer voltage and current ratings.