In a spindle motor in which teeth portions of a stator core formed by laminating magnetic plates are bent in order to increase the number of turns of the stator windings, a gap in the teeth portions between the magnetic plates is avoided and a precise attractive force adjustment becomes possible. The stator core is bent such that its teeth portions faces a surface of a rotor magnet at right angles, and the teeth portions and salient pole arm portions around which windings are wound are substanti...

A smoke and heat alarm system employing a pulse-forming transmitter to produce a ringing perturbation in the household line voltage when actuated. This perturbation is sensed by a remote alarm device on the same line to produce a remote alarm. An optical smoke detector which is relatively insensitive to line voltage variations is employed in the transmitter of the alarm system.

A compacted magnetic powder metal component assembly for use in an electrical machine is provided. Each component assembly has a top section and a bottom section.Each top section is comprised of a generally cylindrical center portion, a plurality of winding supports extending radially outward from the center portion and a core segment at a radial edge of each winding support.Each bottom section is comprised of a generally cylindrical center portion, a plurality of winding supports extending radi...

A vehicle alternator has a rotor having plural claw poles and a stator placed at the outer circumference of the surface of the rotor. Plural grooves are formed in a specified rear area on a surface of each claw pole faced to the stator. The specified rear area is an approximate rear half area on the surface of the claw pole along a rotating direction of the rotor. The grooves are formed in parallel to each other. Each groove has one or a combination of a U-letter shaped groove having a circulati...

A spindle motor including a rotor hub which is rotationally driven by a magnetic action of a rotational magnetic field generated when a current is applied to a wire wound around teeth of a stator core and a magnetic field of a magnet provided on a rotor. Herein, the stator core formed by laminating magnetic steel plates is mounted to an outer periphery of a supporting part of a rotation support shaft of the rotor hub, and the supporting part is made of sintered metal containing a ferromagnetic m...

An electric motor stator including a yoke having a plurality of yoke laminations. A body portion is formed as part of each of the plurality of yoke laminations. A first tooth is continuous with the body portion and is formed as part of at least a portion of the plurality of yoke laminations. The first tooth defines a first tooth profile. A first tooth attachment portion is formed as part of the plurality of yoke laminations. A second tooth includes a plurality of tooth laminations. Each tooth la...

An electric motor, power tool using the electric motor, and method of making the electric motor includes making a stator that includes pole portions that have axial lengths less than an axial length of a back iron portion. Alternatively, or in addition, the pole portions have axially opposed ends that decrease in width. Alternatively, or in addition, the pole portions have dovetail features that are received in corresponding recesses of the back iron portion.

A stator adapted for driving rotation of a rotor includes a stator body having a surrounding wall surface that surrounds a stator axis. A plurality of magnetic pole protrusions protrude radially from the surrounding wall surface relative to the stator axis, and a plurality of stator coils are respectively wound around the magnetic pole protrusions. A signal transmission unit is electrically coupled to the stator coils. Each of the magnetic pole protrusions has an outer periphery, and a recess fo...

A motor core coated with a multi-layer insulating film. The insulating film preferably includes in order: an electrodeposited coating film applied upon an outer surface of the motor core; a first spray coated insulating film applied upon an outer surface of the electrodeposited coating film the first film having a pencil hardness of between about 2H and 4H; and a second spray-coated insulating film applied upon an outer surface of the first spray-coated insulating film, the second film having a ...

A stator for an electrical machine is proposed that has a stator winding (45) that is held by a stator core (10) that is formed into an annular shape. The stator core (10) has grooves (14) and teeth (13) on its radially inwardly oriented circumference. The stator core (10) is composed of layered stator sheet metal lamellae (11), the direction of the layers defining an axial direction (a). It is provided that at least a first stator sheet metal lamella (20) has a higher flexural strength than sec...