Abstract
The designs and the performances of the chock type constant wattage ballasts are discussed. The fundamental quantities for design, such as the reactance values of the linear chock coil and turns ratio of the saturable auto-transformer related to as function of the auto-transformer secondary voltages under normal operation and variable K, which are indicated by ratios of the magnetizing current of the auto-transformer referred to the secondary to the rated lamp current, besides the line and lamp ratings. It is then carried forward according with the particular specification to design the linear choke coil and the saturable auto-transformer in terms of window and core cross sectional areas, core and copper volumes and others, and then, the electrical characteristics, such as the lamp wattage regulation, the lamp current crest factor, and the ballast losses, are investigated from various points of view, such as variable K, the secondary voltage and the flux density of the auto-transformer under normal operation, coefficient of specific voltage, and others.
