Abstract: A variable speed rotary electric machine comprises a stator composed of a stator core and first and second stator windings wound on the stator core, and a cage rotor mounted rotatably within the stator and composed of a rotor core and rotor conductor disposed in a squirrel-cage configuration. The first stator winding is connected to an AC power supply of a fixed frequency. The second stator winding is connected to a power supply of a variable frequency. The first and second stator windings are so wound as to form, respectively, numbers of poles differing from each other. The rotor conductors of the cage rotor are electromagnetically coupled with the magnetic flux generated by the first and second stator windings, respectively, and so disposed as to form a number of poles which is intermediate between the number of the poles formed by the first stator winding and the number of poles formed by said second stator winding.

Abstract: A novel armature of an electric rotating machine is disclosed. The armature core is divided axially into two or more members. The coils of the armature winding are fixed on the armature core in such a way that two or more coil sides are disposed in each slot of one member, and the coil sides disposed in the same slot are arranged in adjacent different slots of the other member. The end of each coil is positioned in a manner to substantially equalize the mutual inductance between each pair of adjacent coil ends.

Abstract: The first and second interpole compensation windings are disposed on the commutation starting side and the commutation ending side of the interpole cores, respectively. The current flowing through the first and second interpole compensation windings are controlled in response to the first and second voltages detected by the first and second brushes disposed on the commutation starting side and the commutation ending side of the brushes.

Abstract: In a stator provided with interpoles, a magnetic flux adjusting winding is provided adjacent to the radially inner end of each interpole core for adjusting the magnetic flux passing through the half of the circumferential width of the interpole core, so that the intensity of the magnetic flux passing through the radially inner end of the interpole core becomes substantially uniform along the end face of the interpole core, whereby the waveform of the commutating emf is simulated to that of the reactance voltage to widen the width of the no-spark zone during commutation thereby improving the commutation performance without appreciably modifying the original shape or structure of the stator.

Abstract: A brush holder for dynamo-electric machine has the following parts: a brush making sliding contact with the surface of a rotary collector; a stationary holder part fixed to the stationary part of the dynamo-electric machine opposite to the collector; and a detachable holder part detachably secured to the stationary holder part and holding the brush when separated from the stationary holder part, the detachable holder part being provided with a retainer that clamps the brush when the detachable holder part is separated from the stationary holder part and unclamps the brush when it is attached to the stationary holder part, the brush clamping portion and the portion of the retainer therearound being coated with a coating film of a material having a friction coefficient smaller than the material of the retainer. This arrangement obviates various unfavorable phenomena such as jumping of the brush, sparking on the sliding surface, cracking in the brush and so forth.

Abstract: When an induction motor is speed-controlled with a variable frequency power supply including thyristor inverters, operating loss due to harmonics components is increased in a rotor of the induction motor. In order to diverge additional operating loss into an appreciable depth of the rotor to thereby suppress the increase in the operating loss, the rotor comprises a cylindrical member having a circumferential resistivity which is larger than axial and radial resistivities and circumferential permeability which is smaller than axial and radial permeabilities, and a core disposed in the cylindrical member and having an axial permeability which is smaller than circumferential and radial permeabilities.

Abstract: A fault detection apparatus for a rotor winding of a rotary machine comprises a peak value hold circuit, a peak value processor and a monitor. The peak value hold circuit holds peak value of a pulsing magnetic flux waveform supplied from a magnetic flux sensor mounted in proximity to a surface of a rotor, for a necessary time period. The peak value processor sequentially compares the peak value held in the peak value hold circuit with corresponding one of pre-stored peak values of the pulsing magnetic flux waveform to determine if a difference therebetween exceeds a preset level. The monitor indicates the presence or absence of fault based on the result of the comparison of the processor.

Abstract: At least one circumferential slot is provided at a predetermined axial position on an armature core so as to cross axial slots receiving a plurality of coil sides of an armature winding and to communicate adjacent axial slots, and the plurality of coil sides to be generally mounted in the same axial slot are partially shifted from one slot to an adjacent one through the circumferential slot so that the coil sides of the armature winding are partially arranged to extend through adjacent slots at a fixed, predetermined circumferential distance. In this manner, the generation of commutating spark is substantially prevented and the commutating performance is improved.

Abstract: An electric rotary machine is provided with a stator having a stator core of laminated iron plates with a given lamination thickness in an axial direction of the machine and a stator winding wound around the core and a rotor rotatably disposed inside the stator, having a rotor core and a rotor winding. The axial length of the stator core is selected with respect to that of the rotor core in such a way that, when the rotor is thermally extended, the end of the rotor core never extends beyond the end of the stator core. With such a constructional arrangement, there is eliminated an excessive temperature rise at the ends of the stator core, and prevented an insulation deterioration of the stator winding and the burning of the stator core.

Abstract: A cooling system for a rotary electric machine having a stator including a stator core and a stator frame for supporting the stator core and a rotor including a yoke, a plurality of salient magnetic poles mounted on the periphery of the yoke and shield plates bridging the tips of the adjacent magnetic poles wherein the cooling system comprises groups of air-discharging and air-charging ducts radially penetrating the stator core, each group of the ducts being axially aligned with a predetermined distance from each other and air-discharging windows formed in the shield plates at predetermined axial positions thereof, and the axial area of each group of the air-discharging ducts is larger than the axial area of the air-discharging window of the corresponding shield plate thereby increasing the flow rate of the cooling air through the rotary machine.

Abstract: In a gap winding type electric rotary machine, a stator winding consisting of a plurality of stator coils is mounted on the inner surface of a stator core within the air gap defined by the clearance between the stator core and the rotor core, in such a manner that the stator coils are grouped together in a plurality of stator coil units and each stator coil unit is encapsulated in a solid casing comprising an outer cover fixed to the inner surface of the stator core through an elastic sheet and an inner cover closing the outer cover. The inner clearance within the solid casing is also provided with an elastic sheet.

Abstract: A gap winding type dynamo-electric machine, in which armature windings are supported in a gap between a rotor and a slotless slator and along the inner periphery of the stator by supporting means carried by the stator such that they are capable of displacement relative to the stator in the circumferential direction or in both circumferential and axial directions, whereby deformation of the armature windings or damage to their insulating layer due to inflow of short-circuit current or sudden change of load is prevented.

Abstract: A novel winding assembly of the gap winding type electric rotary machine is arranged on the inner periphery of the slotless magnetic core of the machine. The winding comprises a plurality of congregated twisted strands each including a plurality of insulated thin wires. The congregated strands are twisted in opposite directions in such a manner as to offset the effect of magnetic fluxes produced in adjacent twisted strands axially thereof, thereby reducing the reactance of the winding on the one hand and dampening the vibration and propulsive force which otherwise might be generated in the electric rotary machine.

Abstract: An end of an end cover provided on a fixed electromagnetic device is arranged in spaced opposition to the side wall of spider arms which are perpendicular to a rotary axis, the spider arms being projected radially from the rotary shaft. The end of the end cover is positioned midway of the spider arms on the radii thereof, thus substantially eliminating the fan loss of the rotary electric machine.

Abstract: A stator for an electric rotary machine adopting a so called gap winding system in which the stator winding is arranged on the smooth inner surface of the stator core. The winding strand groups arranged on the inner surface of the annular stator core are fixedly secured to cooling pipes formed in a cylindrical frame, so that the cooling pipes support the winding strand groups thereby to facilitate transportation and assemblage of the stator winding on the one hand and to provide a sufficiently rugged stator winding to withstand the mechanical stress due to vibrations or electrical short-circuiting which are caused during the running of the electric rotary machine.

Abstract: A plurality of salient poles and a stator are adapted to be cooled only by cooling gas which is passed through a plurality of fluid passageways formed in a yoke of a rotor. By the arrangement that all the cooling gas discharged through the fluid passageways is used for cooling the rotor and the stator, cooling efficiency can be increased due to enhanced flow characteristics of the cooling gas.