Electronic ballast for transilluminators and crosslinkers

Abstract

A low cost multipurpose electronic ballast for ultraviolet transilluminators and crosslinkers for starting and operating four or more ultraviolet lamps simultaneously. The electronic ballast is designed to be capable of operating with input voltages ranging from 85 volts AC to 250 volts AC and input frequencies ranging from 40 Hertz to 400 Hertz. The output to the lamps comes from a group of capacitors which control the current to the lamps. Because the output comes from capacitive ballasts in parallel, alternate sets of capacitors can be switched to alternate sets of lamps allowing the central ballast control to be used with different sets of lamps. By placing another set of capacitors in parallel with the existing output capacitors and making a momentary connection, a momentary power boost can be achieved. This feature also allows a variable intensity control comprised of a number of different size capacitors in series with the parallel group to vary the total current to all the lamps. Variable intensity can also be accomplished by reducing the input voltage with a variable resistor. These variable intensity controls can not reduce intensity to zero, but provide sufficient intensity variation range for the application. Changing the output capacitors provides the required current for different lamp wattages. This application is specifically designed for use with ultraviolet transilluminators and crosslinkers, allowing features not previously available. It is not beneficial for industrial lighting.