The load characterstic of a dynamo giving constant current over a large range of speed

A graphical method of predicting the characteristics of a constant-current dynamo, such as the Rosenberg or Brolt, has been developed and, in the Appendix, the formula derived by the late Dr. Kapp has been extended to determine the maximum current flowing in the short-circuited paths of the armature, and the steady value of the load current. It is also shown that the maximum value of the short-circuit current occurs when the load current reaches half its final value. Tests carried out in the Laboratories of Applied Electricity of the University of Liverpool on a non-salient-pole machine are cited to show that the constant-current characteristic of the Rosenberg dynamo may be attained without the use of slotted or salient poles.