The experimental determination of the regulation of alternators

The method of determining the regulation of an alternator from test results which is incorporated in the Standardization Rules, is not accurate for low power factors, as it takes no cognizance of varying pole leakage or of the ratio of armature reaction to reactive voltage drop. The effects of these are most marked at power factor zero, and as this is also the only power factor at which a load regulation curve can usually be experimentally determined satisfactorily, it is advocated to base regulation determinations upon the power factor zero load saturation, and the no-load saturation.