Bushing balance controller and method of using same

Abstract

A bushing balance controller senses the temperature of each section of a multiple section glass fiber forming bushing by thermocouples or resistance (voltage drop) measuring techniques and injects electrical energy to all but one of the individual bushing sections and adjusts the supply of electrical energy to the entire bushing assembly thereby controlling the temperature of each individual section of the bushing. When thermocouples sensors are utilized, standard thermocouple driven temperature controllers may be utilized to provide a signal to a plurality of power packs, a primary power pack providing electrical energy to the entire bushing and smaller power packs controlling the injection of electrical energy to all but one of the bushing segments. A similar power pack and bushing control scheme accompanies the use of resistance (voltage drop) measurement techniques. Here, however, the control signal is generated by an error signal representative of the present, sensed temperature versue the set point temperature. In order to eliminate the interference between the voltage drop sensing and the injected current, an interleaving technique is utilized to sense voltage drop and inject electrical energy during alternate cycles of the applied power.