Abstract: The present invention relates to a method for sensorless control of a permanent magnet motor exhibiting saliency, the method comprising the steps of determining a back electromotive force signal of a non-conducting phase winding of the permanent magnet motor, and applying a first drive voltage to at least one other phase winding of the permanent magnet motor, said first drive voltage being phase-shifted relative to the determined back electromotive force signal. Moreover, the present invention relates to a control system for carrying out the above-mentioned method.

Abstract: The invention provides a rotor for an electrical motor. The rotor comprises both a squirrel cage and a number of magnets and can be inserted e.g. in a line-start motor. To secure the magnets in cavities in a core of the rotor, an end plate is attached to one axial end face by rivet means, and to simplify manufacturing of the rotor, the rivet means forms part of at least one of the short circuit rings of the squirrel cage.

Abstract: The invention provides a rotor for an electrical motor, e.g. a line-start motor. The rotor comprises a magnet located in a cavity in a rotor core. The core is laminated from sheets of magnetically conductive material and the magnet is secured in the cavity by an end plate which covers the end face. To avoid short circuiting of the magnet, an aperture is provided in the end plate such that a first portion of the opening into the cavity is in communication with the aperture and such that a remaining, second, portion of the cavity is covered by the end plate to secure the magnet in the cavity independently upon the orientation of the end plate around the center axis.

Abstract: The invention provides a rotor for an electrical motor, a tool for making a rotor core and a method of making the rotor. The rotor could be incorporated e.g. in a line-start motor and comprises a squirrel cage and magnet located in a rotor core. The magnets are, in one end of the rotor, secured by an end plate with apertures which are larger than the magnet openings, and the end plate is indexed relative to the magnet slots such that a first portion of openings into the magnet slots is in communication with the aperture and such that a remaining, second, portion of the magnet slots is covered by the end plate. In one aspect, the end plate forms an integrated part of the rotor core and comprises openings cooperating with conductor slots to form through-going passages for conductors of the squirrel cage. In that way, the end plate is held in a completely fixed position by the squirrel cage which is moulded directly onto the core and into the conductor slots.