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: An electromechanical device having a mechanical interface structure for connecting to an external rotating element, an electrical machine, and one or more gear stages on a mechanical power transmission path between the mechanical interface structure and a rotor of the electrical machine. The electromechanical device also has bearings for connecting the rotor of the electrical machine rotatably to the structure of the electromechanical device. The bearings carry the axial and radial forces of the rotor, and at least partly the axial and radial forces of the driving shaft of the gear stage, directly connected to the rotor.

Abstract: An electromechanical device comprises a mechanical interface structure (101) for connecting to an external rotating element, for example a wind turbine. The device comprises an electrical machine (102-104), and one or more gear stages (105-112) on a power transmission path between the mechanical interface structure and a rotor of the electrical machine. The device further comprises mechanical structures (113-115) constituting a common lubricant oil room for both the gear stages and the electrical machine. The electromechanical device comprises oil channels (116a) for directing lubricant oil circulated in the device to flow via the gear stages and via bearings (118, 119) of the electrical machine. Therefore, a common lubricating system can be used for both the gear stages and the electrical machine.

Abstract: An apparatus comprises a processing system (201) configured to produce voltage control signals for controlling an electrical machine (202) comprising two or more multiphase stator windings. The processing system is configured to produce the voltage control signals on the basis of rotation-converted stator currents expressed in a coordinate system bound to a rotor of the electrical machine and on the basis of a model of the electrical machine modeling at least inductances of the multiphase stator windings and mutual inductances between the multiphase stator windings. The processing system is configured to convert phase currents of the multiphase stator windings into the rotation-converted stator currents with a conversion rule corresponding to a form of the model of the electrical machine where each of the stator flux-linkages of the model is dependent on only one of the rotation-converted stator currents in spite of the mutual inductances between the multiphase stator windings.

Abstract: An apparatus comprises a processing system (201) configured to produce voltage control signals for controlling an electrical machine (202) comprising two or more multiphase stator windings. The processing system is configured to produce the voltage control signals on the basis of rotation-converted stator currents expressed in a coordinate system bound to a rotor of the electrical machine and on the basis of a model of the electrical machine modeling at least inductances of the multiphase stator windings and mutual inductances between the multiphase stator windings. The processing system is configured to convert phase currents of the multiphase stator windings into the rotation-converted stator currents with a conversion rule corresponding to a form of the model of the electrical machine where each of the stator flux-linkages of the model is dependent on only one of the rotation-converted stator currents in spite of the mutual inductances between the multiphase stator windings.

Abstract: A method for installing a rotor of an electrical machine is disclosed. The method comprises using axially directed guide bars (107-109) for keeping the rotor (102) centered with respect to a bore of a stator (101) during the installation of the rotor. The rotor has sliding surfaces so that it can be slid in the axial direction to its final position along the guide bars. The mechanical support structure (104) that supports bearings (105, 106) of the rotor are provided with supporting surfaces for being able to give mechanical support to the guide bars. The mechanical support structure (104) may comprise for example threaded holes to which threaded ends of the guide bars can be tightened. After the rotor has been moved to its final position and it is supported by the bearings, the guide bars are removed.

Abstract: Method and system for monitoring the condition of the capacitor arrangement (14-16) of the DC-voltage intermediate circuit of a power electronics appliance, such as of a frequency converter, at the place of usage, in which method the discharge voltage over the capacitor arrangement as a function of time is measured, and in which method the intermediate circuit is pre-charged with a pre-determined DC voltage, the pre-charging is removed from the intermediate circuit, the voltage of the intermediate circuit is measured by sampling at regular intervals, the voltage drop as a function of time is determined on the basis of the measured voltage of the intermediate circuit, the capacitance or the relative change in it is determined on the basis of the voltage drop, the value of the determined capacitance or of the relative change in it is compared to a pre-determined limit value on the basis of the voltage drop, and the necessary condition monitoring procedure is performed when the value determined with the measurem

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 filter appliance comprises first electrical terminals (201-203) for connecting to a multiphase electrical converter device, second electrical terminals (204-206) for connecting to a load, main current coils formed of foil conductors and connected between the first and the second electrical terminals, and shielding coils whose first ends are electrically connected to a third electrical terminal (219) of the filter appliance. Each of the shielding coils is formed of foil conductor that is alongside and a distance apart from the foil conductor of the corresponding main current coil so as to form a capacitive shield between successive turns of the main current coil. When the third electrical terminal is connected to constant electrical potential, the shielding coils reduce the common mode voltage applied to the load and, for example, a risk of bearing damages in an electrical motor driven by a multiphase electrical converter device is reduced.

Abstract: An electromechanical device comprises a mechanical interface structure (101) for connecting to an external rotating element, for example a wind turbine. The device comprises an electrical machine (102-104), and one or more gear stages (105-112) on a power transmission path between the mechanical interface structure and a rotor of the electrical machine. The device further comprises mechanical structures (113-115) constituting a common lubricant oil room for both the gear stages and the electrical machine. The electromechanical device comprises oil channels (116a) for directing lubricant oil circulated in the device to flow via the gear stages and via bearings (118, 119) of the electrical machine. Therefore, a common lubricating system can be used for both the gear stages and the electrical machine.

Abstract: An electromechanical device comprising a mechanical interface structure (101) for connecting to an external rotating element, an electrical machine (102-104, 117), and one or more gear stages (105-112) on a mechanical power transmission path between the mechanical interface structure and a rotor of the electrical machine, wherein the electromechanical device further comprises a bearing means (118, 119) for connecting the rotor (103) of the electrical machine rotatably to the structure of the electromechanical device, which bearing means carry the axial and radial forces of the rotor and at least partly the axial and radial forces of the driving shaft (112) of the gear stage directly connected to the rotor.

Abstract: An electromechanical device comprising a mechanical interface structure (101) for connecting to an external rotating element, an electrical machine (102-104), and one or more gear stages (105-112) on a mechanical power transmission path between the mechanical interface structure and a rotor (103) of the electrical machine, wherein the rotor (103) of the electrical machine is supported by the frame of the gear stage directly connected to the rotor.

Abstract: A method for installing a rotor of an electrical machine is disclosed. The method comprises using axially directed guide bars (107-109) for keeping the rotor (102) centered with respect to a bore of a stator (101) during the installation of the rotor. The rotor has sliding surfaces so that it can be slid in the axial direction to its final position along the guide bars. The mechanical support structure (104) that supports bearings (105, 106) of the rotor are provided with supporting surfaces for being able to give mechanical support to the guide bars. The mechanical support structure (104) may comprise for example threaded holes to which threaded ends of the guide bars can be tightened. After the rotor has been moved to its final position and it is supported by the bearings, the guide bars are removed.

Abstract: A filter appliance comprises first electrical terminals (201-203) for connecting to a multiphase electrical converter device, second electrical terminals (204-206) for connecting to a load, main current coils formed of foil conductors and connected between the first and the second electrical terminals, and shielding coils whose first ends are electrically connected to a third electrical terminal (219) of the filter appliance. Each of the shielding coils is formed of foil conductor that is alongside and a distance apart from the foil conductor of the corresponding main current coil so as to form a capacitive shield between successive turns of the main current coil. When the third electrical terminal is connected to constant electrical potential, the shielding coils reduce the common mode voltage applied to the load and, for example, a risk of bearing damages in an electrical motor driven by a multiphase electrical converter device is reduced.