Abstract: A method of commutating a motor includes calculating an adjustment electrical angle, and utilizing the adjustment electrical angle in a common set of commutation equations so that the common set of commutation equations is capable of producing both one and two dimensional forces in the motor.

Abstract: An induction motor control device includes an inverter circuit for driving an induction motor by outputting a command voltage, a current detector for detecting an output current, a magnetic flux estimation observer for generating an estimated magnetic flux, an estimated current, and a phase command for the motor using the command voltage and the output current, a primary angular speed estimator for estimating a primary angular speed using the estimated magnetic flux, a slip compensator for calculating a slip angular frequency using the output current, a first angular speed estimator for estimating a first angular speed using the primary angular speed and the output current, a second angular speed estimator for estimating a second angular speed using the output current, the estimated magnetic flux, and the estimated current, and a resistance estimator for estimating a secondary resistance value of the motor using the first and second angular speeds.

Abstract: An arrangement to provide variation of the speed or other operating parameters of an electrical machine without connection to the rotor. The machine is of the induction type having a winding in separate parts to create a flux movable in the air-gap different speeds by the alteration of current in a part of the winding. In one example the current is altered by a variable impedance connected to one winding part, the other part being connected to an electrical supply.Another example, FIG. 6, shows two machines (NM.sub.1, NM.sub.2) arranged to drive a rail vehicle through smooth rail wheels attached to the machine rotor axles. A single, variable-frequency, inverter (NI) drives both machines and is connected to part (MP) of each machine winding. Other parts (AP) of each machine winding are connected together by a link (NC). In operation power (real or reactive) is transferred between the machines along the link to equalize the torque of the machines.

Abstract: A commutator motor can be set to different speeds by changing the external circuit connections between the single phase AC supply line and the stator field winding. The field winding is distributed in slots over at least part of the circumference of the stator bore and the field winding connection is switched, when going from a lower to a higher speed, in such a way that the axis of the stator field is rotated in the direction of rotation of the motor. For improved performance, the number of excitation turns may also be changed, simultaneously with the rotation of the field axis. The motor is particularly useful for automatic washing machine drives having a universal motor.