Influence of A-C reactance on voltage regulation of 6-phase rectifiers

INVESTIGATIONS made during the past few years have shown that methods normally used for the calculation of rectifier voltage regulation have definite limitations not generally appreciated by application engineers. It has been established that conventional methods of calculating regulation are valid only if the angle of overlap is less than 300 degrees divided by the number of phases. With larger overlap angles any a-c reactance common to two or more simple rectifiers introduces a delay angle, even though the rectifiers are operated without intentional delay. This inherent delay reduces the direct voltage and therefore increases the voltage regulation. In special applications involving large overlap angles, these limitations are of primary importance, because considerable error is possible if they are not recognized.