A helical armature is a form of air-gap electric motor or generator armature wound in a helical fashion as opposed to a conventional random or orthocyclic winding. Such a design is of interest in superconducting motor and generation technology, ^[1] though comparatively little research has been done on the subject. An important and remarkable feature of helical armature windings is that they have no end windings. ^[2] Moreover, as each conductor follows a helical path of constant pitch, helical windings are not easily divided into active and end regions. ^[1] An important downside, though, is that such armatures provide poor winding factors. ^[3]

Use in motors

Motors of helical armature design have a lower winding resistance, allowing the motor to run more efficiently, and giving it a longer lifespan. ^[2] Helical windings also provide low inertia and smooth torque for low-speed DC motors. ^[1] A disadvantage is that they have relatively low winding ratios. ^{[3] [2]}

Use in generators

An advantage of helical armature windings in superconducting generators is that they have higher VA ratings, lower armature resistance, and lower synchronous reactance. ^[3] Future superconducting generators would benefit from a helical winding because due to the absence of active and end zone it can be supported uniformly, unlike a conventional winding. There is a <10% loss in motor flux though, but this would be compensated for by the various advantages in this design. ^[1]

See also

• Coil winding technology

References