Voltage regulation of generators

The voltage regulation of generators was recognized to be an important factor in central station operation as early as the first installation of the Edison bi-polar generator. At the time these generators were first installed it was found that owing to the poor regulation of the prime movers, which were very poor regulating engines, that with fluctuating loads lighting was not very satisfactory when connected to the same dynamo which operated power loads, and in order to produce constant voltage a regulator, which was practically an automatic rheostat having the rheostat switch controlled by a solenoid, was designed.