Vernier hybrid machines

The vernier hybrid machine is a member of the family of variable-reluctance permanent-magnet machines. It develops high specific torque by means of a magnetic gearing effect but it suffers from low power factor. The construction of the machine is simple. Analytical formulae are derived for specific torque and power factor. The formulae may be used to find a suitable compromise between the desire for high specific torque and for good power factor. Static torque tests taken from a small laboratory machine are in satisfactory agreement with theory.