Electric Engine‐Testing Plant: The Type of Equipment Used in a Modern Electrical Aero‐Engine Test Laboratory

THE present rapid progress in the development of internal‐combustion engines necessitates rapid and accurate testing methods, and it has been the aim of the electrical industry to produce braking equipment with which the power output can be conveniently and exactly measured. These devices are termed “Electric Dynamometers” and consist of an electric generator, the frame of which is not rigidly secured but so supported as to be able to be swung slightly about the axis of the rotor. This arrangement is no different in principle from the well‐known Prony brake, since the brake‐drum and blocks of the latter are merely replaced by the rotor and swinging frame respectively of the electric machines.