Normalised high-speed performance analysis of small hybrid stepping motors

Despite the widespread use of hybrid stepping motors, the relationship between the parameters of the motor/drive combination and the steady-state capability is not widely understood. The steady-state behaviour of hybrid motors with constant-voltage variable-frequency supplies is analysed, using the Blondel circle diagram to illuminate the power conversion process, and identify the parameters which govern the maximum output power. It is shown that in spite of their apparent complexity, all hybrid motor/drive packages can be characterised by three simple parameters. This permits their theoretical steady-state performance to be displayed in the form of normalised operating point traces.