Induction type electric motor drive actuator system
AssigneeRotork Controls Limited
InventorsGraham M. Ogden, Robert Pearce
Life of this patent
Estimating the term…
Abstract
An actuator driven by an electric motor of the polyphase or single phase induction type has a stator with power windings as well as a rotor. At least one fixed fluxed sensor independent of the power windings is provided. The at least one sensor is arranged in an air gap between the stator and the rotor of the induction type motor such that the voltages induced in the at least one sensor represent a measure of the magnetic flux existing in the air gap. The flux sensor which is a preferably sensing winding provides a flux signal. An output signal representing the instantaneous output torque of the motor is generated by multiplying the flux signal by the electric current flowing through one or more of the stator power windings.
Claims21
An actuator comprising an electric motor of the polyphase induction type having a stator with power windings and slots therefore and also having a rotor, and in which only a single flux sensor is provided, the flux sensor being a single sensing coil wound in the stator slots and independent of the power windings, the sensing coil being so arranged that voltages induced therein represent a measure of the magnetic flux existing in an air gap between said stator and said rotor of the motor;
- the actuator further comprising current sensing means associated with one or more of the stator power windings, and means responsive to signals from the current sensing means and the flux sensor to obtain a motor torque signal representing the instantaneous output torque produced by the induction motor.
Dependencies are inferred from the claim text.