Abstract: A rotor of an induction machine includes a rotor core structure and a cage winding. The cage winding includes rotor bars in slots of the rotor core structure and end-rings connected to ends of the rotor bars. The ends of the rotor bars are attached to openings of the end-rings by expansion of the ends of the rotor bars in transverse directions of the rotor bars caused by axial press having been directed to the ends of the rotor bars. The material of the rotor bars is softer than the material of the end-rings. Thus, unwanted shape deformation of the end-rings can be avoided when the ends of the rotor bars are axially pressed. The material of the end-rings can be for example copper alloy with additions of chrome and zirconium, whereas the material of the rotor bars can be for example copper.

Abstract: Each permanent magnet module for a permanent magnet rotor includes a base-plate and a permanent magnet element attached to the base-plate. The base-plate includes a bottom section and an upper section between the bottom section and the permanent magnet element. The permanent magnet modules constitute subsets so that permanent magnet modules of different subsets differ from each other by positions of the upper sections of the base-plates with respect to the bottom sections of the base-plates so that the permanent magnet elements of the permanent magnet modules of the different subsets are axially successive and circumferentially shifted when the bottom sections of these permanent magnet modules are axially successive and circumferentially aligned. Thus, the permanent magnet elements of the permanent magnet modules can be arranged into, for example, skewed rows on a surface of the rotor.

Abstract: A rotor of an induction machine includes a rotor core structure and a cage winding. The cage winding includes rotor bars in slots of the rotor core structure and end-rings connected to ends of the rotor bars. The ends of the rotor bars are attached to openings of the end-rings by expansion of the ends of the rotor bars in transverse directions of the rotor bars caused by axial press having been directed to the ends of the rotor bars. The material of the rotor bars is softer than the material of the end-rings. Thus, unwanted shape deformation of the end-rings can be avoided when the ends of the rotor bars are axially pressed. The material of the end-rings can be for example copper alloy with additions of chrome and zirconium, whereas the material of the rotor bars can be for example copper.

Abstract: Permanent magnet modules for a permanent magnet rotor are presented. Each permanent magnet module comprises a base-plate and a permanent magnet element attached to the base-plate. The base-plate comprises a bottom section and an upper section between the bottom section and the permanent magnet element. The permanent magnet modules constitute subsets so that permanent magnet modules of different subsets differ from each other by positions of the upper sections of the base-plates with respect to the bottom sections of the base-plates so that the permanent magnet elements of the permanent magnet modules of the different subsets are axially successive and circumferentially shifted when the bottom sections of these permanent magnet modules are axially successive and circumferentially aligned. Thus, the permanent magnet elements of the permanent magnet modules can be arranged into, for example, skewed rows on a surface of the rotor.

Abstract: A rotor for a permanent magnet machine includes first and second axially successive rotor sections each including permanent magnets generating magnetic field having a pole pitch. The rotor includes a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section. The second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set the stator flux-linkages generated by the first and second rotor sections to be substantially zeroes. Thereafter, the permanent magnets do not substantially induce voltages on the stator windings even if the rotor is rotating during for example an internal fault of stator windings.

Abstract: A rotor for a permanent magnet machine includes first and second axially successive rotor sections each including permanent magnets generating magnetic field having a pole pitch. The rotor includes a first coupling system for connecting the first rotor section to a shaft and a second coupling system for connecting the second rotor section to the shaft or to the first rotor section. The second rotor section is rotatable with respect to the first rotor section by an angle corresponding to the pole pitch in response to releasing the second coupling system so as to set the stator flux-linkages generated by the first and second rotor sections to be substantially zeroes. Thereafter, the permanent magnets do not substantially induce voltages on the stator windings even if the rotor is rotating during for example an internal fault of stator windings.

Abstract: A permanent magnet module for a rotor of a permanent magnet electrical machine is presented. The permanent magnet module comprises: a stack of ferromagnetic steel sheets (104) having a groove in the direction perpendicular to the ferromagnetic steel sheets, and a permanent magnet (105) located in the groove and arranged to produce magnetic flux that penetrates a surface (106) of the stack of ferromagnetic steel sheets. The surface has a shape suitable for forming a desired magnetic flux density distribution into an air-gap of the permanent magnet electrical machine. The permanent magnet module further comprises a base-plate (102) made of solid ferromagnetic steel. The base plate is located at an opening (116) of the groove and constitutes together with the groove an aperture in which the permanent magnet is located.

Abstract: A permanent magnet module for a rotor of a permanent magnet electrical machine is presented. The permanent magnet module comprises: a stack of ferromagnetic steel sheets (104) having a groove in the direction perpendicular to the ferromagnetic steel sheets, and a permanent magnet (105) located in the groove and arranged to produce magnetic flux that penetrates a surface (106) of the stack of ferromagnetic steel sheets. The surface has a shape suitable for forming a desired magnetic flux density distribution into an air-gap of the permanent magnet electrical machine. The permanent magnet module further comprises a base-plate (102) made of solid ferromagnetic steel. The base plate is located at an opening (116) of the groove and constitutes together with the groove an aperture in which the permanent magnet is located.

Abstract: An electric machine which has an arched stator and a cylindrical rotor fitted inside it and in which the flux flows in the radial direction between the stator and the rotor as in a permanent-magnet radial-flux synchronous electric machine, and in which the stator of the machine consists of stator segments (2), each of which has an independent stator core and winding, and the stator segments are arranged to be physically separate from each other so that the stator consists of stator segments arched according to the radius of the rotor and working electromagnetically independently like a linear machine, each stator segment having a stator core and a winding separate from the other stator segments, and that it comprises an overhead supporting frame structure separate from the stator cores and consisting of several longitudinal ribs (41) and parts (42) between them.

Abstract: An electric machine which has an arched stator and a cylindrical rotor fitted inside it and in which the flux flows in the radial direction between the stator and the rotor as in a permanent-magnet radial-flux synchronous electric machine, and in which the stator of the machine consists of stator segments (2), each of which has an independent stator core and winding, and the stator segments are arranged to be physically separate from each other so that the stator consists of stator segments arched according to the radius of the rotor and working electromagnetically independently like a linear machine, each stator segment having a stator core and a winding separate from the other stator segments, and that it comprises an overhead supporting frame structure separate from the stator cores and consisting of several longitudinal ribs (41) and parts (42) between them.

Abstract: The invention relates to a procedure for preparing the windings for an electric motor. The magnetic core (20) of the stator and/or rotor of the motor is provided with slots (24,25) in which winding coils (2; 5,7;15,17) can be fitted. According to the invention, the winding coils (2) are wound from winding wire and shaped substantially into their final form, the cross-section of the coil sides (15,17) corresponding to the space reserved in the slot (24,25) for the coil. The winding coils (15,17) are fitted in place in the slots (24,25) provided in the magnetic core.

Abstract: A method and an apparatus for damping the vibrations of an alternating current motor is provided. The motor is supplied from an alternating current source with a supply voltage whose frequency is the basic frequency. Additionally the motor is fed with a second voltage having a frequency equal to the basic frequency multiplied by the quantity 2*m*q−1. In the equation, m is the number of the phases of the motor and q is the number of slots per phase.