Some characteristics of the single-phase travelling-wave machine

A single-phase axial-flux travelling-wave machine is described, which has series connected windings on a doublesided linear stator block, and shunt connected capacitors. When driving an aluminium disc, the force/speed curve is similar to that of a conventional 3-phase linear induction motor. The maximum speed, however, can be changed by changing the shunt capacitance. With a fixed value of shunt capacitance, and when the machine is loaded, there is a contraction in wavelength, i.e. the travelling-wave machine is found to have no fixed synchronous speed. There is also attenuation that increases as the rotor speed falls. The paper includes an analysis based on a simplified model using the current-sheet method.