Series and Parallel Coupling of Dynamos

—Since the output of a dynamo is made up of two factors, viz.: the pre ure and the current respectively, it follows that the output of a machine may be enlarged by increasing either one or the other, or both at the same time. As, however, the systems of distribution in use at the present time involve the maintenance of either a constant current or a constant pre ure in a circuit, the methods of coupling dynamos together resolve themselves into two kinds, corresponding to the systems of distribution, viz.: parallel and series connections, In coupling two or more machines in parallel, the pre ures of all the machines are. kept at a constant value, while the output of the plant is inereased in proportion to the current capacities of the machines in circuit. In the series coupling, the current capacity of the plant is kept at a constant value. while the output is increased in proportion to the pre ures of the machines in circuit.