A self-excited compensated alternator

One of the chief disadvantages of the small alternator compared with the d.c. generator of similar output has been the difficulty in obtaining substantially constant output voltage under all conditions of load without the use of some type of external automatic voltageregulator. This paper describes a machine which overcomes this difficulty and which can be built in a frame no larger than that of a standard alternator plus exciter. Over-compounding can be obtained if necessary, the degree being adjustable after construction. The theory of the machine is discussed, and results of calculation and test are given.