Extended-range angular rotary pick-off

The paper describes a proposed new type of extended-range angular pick-off which has characteristics that could prove superior in certain respects to existing devices. AC rotary pick-offs currently being manufactured have a linear output voltage over an angular range of 70°. The object of the work is to design and construct a prototype pick-off which has a linear output voltage over an angular range of 90°. The extended range of linearity is achieved by two offset concentric excitation windings and an offset rotor, giving a constant mutual flux over a range of 90° of rotor angle relative to the stator. The paper is mainly concerned with the design, construction and testing of the prototype pick-off. It is felt that this pick-off has successfully achieved its objectives and can be a very useful addition to the present-day limited-range pick-offs.