Fig. 784.—Parallel system of distribution. This is a constant voltage system and is used principally for incandescent lighting and electric motor circuits.
The first is the least harmful and may be counteracted by running the dynamo at a little higher voltage; but the second and third are very objectionable and difficult to overcome. They are counteracted successfully in practice, however, by various methods of regulation, the use of boosters, and the operation of dynamos in parallel.
Ques. What are the principal applications of parallel or constant pressure systems?
Ans. They are used on practically all incandescent lamp and electric motor circuits, and on some arc lamp circuits.
Ques. Why is it specially applicable to incandescent lamp circuits?
Ans. Incandescent lamps cannot be made to stand a pressure much over 220 volts, and therefore have to be operated on low voltage systems.
Ques. What is the principal disadvantage of a parallel system as compared with a series system?
Ans. The greater cost of the copper conductors.