Abstract: A miniature electric rotating machine has a stator equipped with a field pole on a peripheral circle of a rotor, and the field pole is constituted by a permanent magnet. Each permanent magnet of a miniature electric rotating machine of this type can be divided into a magnetizing side and a demagnetizing side with respect to armature reaction. In the permanent magnet of the present invention, an end portion on the demagnetizing side, which has directivity different from the magnetizing directions on the magnetizing and demagnetizing sides, is disposed adjacent to the portion on the demagnetizing side.

Abstract: A sliding current collector comprises a pair of sliding members which are slidable relative to each other for supply and reception of current through sliding surfaces of the paired sliding members wherein the two sliding members are made of conductive ceramics, and the sliding surface of each of the sliding members has a film surface made of a soft conductive material which is softer than the conductive ceramics so that the sliding current collector can suppress variations in contact voltage drop across the sliding surfaces.

Abstract: A direct-current machine having a rotor which includes a commutator, an armature core and an armature winding and is sustained rotatably in a field system constituted by a cylindrical housing and permanent magnets disposed inside the same. A demagnetizing force of an armature reaction due to an armature current is reduced by attaching a magnetic plate made of high saturation magnetic flux density material to a part of the pole-face of said field system of permanent magnets which is in the demagnetizing field.

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 cooling device for an electrical rotating machine is provided. The cooling device comprises; a yoke of an electric motor, end brackets and a rocker positioned in the outer circumferential portion of a commutator and fastened through the mediary of ventilation spaces to the inner circumference of one of the aforesaid end brackets. The cooling device further comprises; a screening plate for controlling the direction of cooling air being blown and a strength thereof, which is disposed between one end of the aforesaid rocker and the yoke; and a forcibly blowing device. With this cooling device, the cooling air is introduced through ventilating spaces defined radially inwardly of the aforesaid one end bracket into an electric motor by the forcibly blowing device, thereby forcibly cooling the surface of the commutator and the peripheral portion thereof.