An inductive, frequency generator having first teeth-like protrusions provided in at least one of two first annular regions of a magnetically excited stator one of the first annular regions being divided into at least two arcuate portions. Further substantially identically shaped teeth-like protrusions are provided in at least one of two further annular regions of a rotor. The rotor and stator are positioned close to one another with their respective annular regions and teeth-like protrusions opposed to define two air gaps and constitute at least two distinct magnetic circuits. First and second partial windings are respectively positioned about portions of the respective magnetic circuits and are connected for additively summing induced useful voltages produced by magnetic flux changes resulting from rotation of the rotor. The magnetic circuits are excited by steady magnetic fields oppositely directed with respect to the orientations of the partial windings. Voltages produced by interfering magnetic fields are substantially reduced or cancelled, while the useful voltages are additively summed.
A high speed inductor alternator employs axial air gaps, enabling a nonmagnetic filler in the portion of the gap extending into the solid rotor to be securely bonded to the rotor against the action of centrifugal force. This configuration permits use of axial poles on the rotor, and results in a machine that is substantially shorter, axially, than a conventional radial air gap inductor alternator of comparable output ratings.
A speed sensor for a vehicle wheel has a rotating tone wheel and a stationary E-shaped magnetic sensor having a sensing pole of square loop magnetic material positioned between two switching poles. A coil is wound on the sensing pole and the poles are magnetized to periodically reverse the flux in the sensing pole as the teeth on the tone wheel alternately pass the switching poles to induce a signal voltage in the coil corresponding to wheel speed and substantially free of noise components due to misalignment and vibrations of the tone wheel upon relative rotation of the tone wheel and magnetic sensor.
A speed sensor for a vehicle wheel having a rotating tone wheel and a stationary magnetic sensor with a sensing pole proximate the tone wheel teeth and a compensating pole proximate the tone wheel spaced from the tone wheel teeth. The sensing pole and compensating pole are secured to the ends of a permanent magnet in U-shaped configuration and coils connected in series opposition are wound on the sensing and compensating poles. Noise components generated in the sensing coil with the speed signal voltage due to axial misalignment and vibration of the tone wheel are cancelled by corresponding noise components generated in the compensating coil to provide a substantially noise free signal voltage corresponding to wheel speed.
In order to improve the torque per weight ratio in electrical machines for a lower price it is proposed to use a segmented stator design. The segmented stator design is based on general E shaped cores traditionally used for single-phased transformers and inductors, The E-cores has a coil around the centered leg and is assembled parallel to the rotor axis, which means it will function with the transverse flux principle. A radial flux principle can also be performed with the E-cores if the E-cores are divided into two U-sections with a full pitch winding in between them. A clear extra advantage with the E-cores is short flux paths meaning less steel has to be magnetised. For a low volume production standard E-cores can be used making the investment in production facilities smaller. The E-core machines using the transverse principle can have different pole-shapes such the normal force between the rotor and stator are significantly reduced. This makes unequal designs like a 3 stator- and 2 rotor-pole design practical possible.
