Regulating Over-compounded Dynamos

—It is sometimes desirable, as in central light and power stations, to have a dynamo which will maintain a constant pre ure at a point some distance from the machine. In this case the dynamo is over compounded, or the series coils are wound with a greater number of turns, in order to raise the re ure at the terminals of the machine as the oad increases, and thus compensate for the fall of pre ure in the mains. As it is well to vary the degree of over-compounding, the series coils of such dynamos are usually so proportioned as to give from 10 pel cent to 20 per cent of over-compounding, and a strip or ribbon of German silver or copper is arranged as a shunt to the series coils.