The plural operating circuits of plural lamps on common by-pass circuit for high-pressure mercury discharge

This paper deals with simulations and experiments carried out for circuits with plural number of lag type high-pressure mercury lamps lighted, in which one common by-pass circuit is provided and respective resistance is connected to the power source side of ballast windings. The authors intend to prove that realization of excellent operating circuits with plural number of lamps lighted, where supply voltage at stabilization is expressed by a nearly sinusoidal wave and its power factor is 100%, is possible, in other words, self-inductance of each ballast winding in each operating circuit is made slightly larger than the rated inductance and as far as harmonic current is concerned, tap position of the by-pass circuit is made close to the power source side of each ballast winding. Parameter L/sub b/ and C/sub b/ of the by-pass circuit are set to the correct level. By connecting appropriate value resistances to the power source side of each ballast winding in series, it is proven that simultaneous operation of all lamps becomes possible at starting. For example, the following findings are obtained with four lamp circuits with lamp rated power 200 W. (1) At stabilization, distortion factor of the supply current is as low as 2%, and the power factor is nearly 100%. This is a supply current nearly in-phase with the supply voltage. (2) A total of loss due to the ballast windings, L/sub b/ of the by-pass circuit and resistance connected to ballast winding power source side is as low as 11.4% of the power.