Abstract: An electric motor incorporates a positive temperature coefficient resistor 18 between a supply terminal and a brush. The resistor can be inserted from outside the motor through an aperture 17 in an end cap 2. A body 19 of heat conducting material, also insertable from outside the end cap, can be provided and held against to resistor 18 to alter its effective thermal mass and so adjust its operating characteristics.

Abstract: The motor is for driving viscous loads, e.g. a fan, and comprises a stator (10), a permanent magnet rotor (11), a single phase unipolar winding (13) on the stator, and a permanent magnet (29) fixed relative to the stator with its poles angularly spaced with respect to the axis of the motor. The magnet (29) is positioned so that the magnetic coupling between the magnet (29) and the permanent magnet rotor will create stable rest positions for the rotor only where the winding (13) will be energized and will develop torque when power to the motor is switched on. A Hall integrated circuit (16) is provided to detect the position of the rotor relative to the stator and to alternately energize and not energize the winding (13).

Abstract: In an electric motor having a commutator, when a brush wears the associated brushleaf carrying the brush may snag in gap between commutator segments of the commutator, the rotating commutator dragging a bushleaf around into electrical contact with the other brushleaf. To prevent electrical contact being made directly, or via a common commutator segment, a stop is integrally formed with a holder carrying the brushleaves to limit the movement of the brushleaf.

Abstract: A commutator comprises a commutator base, a plurality of commutator segments, and means securing the segments on the base. Each segment has an integral terminal provided with a slot which is open at one end for receiving a connector portion of an armature winding and which is arranged so as in use to straddle and grip the connector portion to electrically connect the commutator segment to the armature winding. The commutator is pre-assembled in that the segments and the commutator base are formed as a unit prior to mounting the commutator on the armature of a motor and can be connected to an armature winding by a mechanical connection without the application of heat.

Abstract: An assembled commutator for use in a fractional horsepower electric motor comprises a base moulded from thermoplastics and a commutator segment mounted on the base. The segment has a tang for electrical connection to an armature coil, the tang comprising a first radially extending portion and second portion connected to the first portion along a fold line.Wire of the coil is passed may be welded or forged to the tang by pressing together the first and second portions, and heating them electrically.

Abstract: The motor has a plastic holding member which is a sliding fit in a casing of the motor and which supports at least one pair of segment magnets and brush gear for the motor in a fixed angular position relative to one another.

Abstract: A fractional horsepower permanent magnet direct-current motor has a velocity indicating device positioned around the commutator, between the brush gear and the armature. The device comprises a conductor in the form of a square wave copper strip which is printed on a flexible support and centered on a circle about the motor shaft, and a magnet assembly mounted on the armature. Magnet assembly comprises radially extending blades which are formed from plastics bonded magnetic material. The blades are magnetized so that adjacent blades have opposite polarity. As the magnet rotates with the shaft, the blades move relative to the conductor and so induce an electrical signal in the conductor. The signal can be monitored to indicate the motor speed as is generally known. The blades also act as a centrifugal fan, helping to cool the motor.

Abstract: A solderless connection between a wire lead and a terminal of an electric motor is formed by squeezing the lead wire and the terminal together by means a slide member which is affixed in a recess in an end cap of the motor housing. The terminal has a U-shaped portion which receives the wire. A sloping wall of the slide member squeezes the U-shape portion against a side wall of the recess as the slide member is pushed home, causing the terminal to grip the wire, to reduce strain on the electrical connection if the wire is pulled.

Abstract: An armature comprises a winding having a connector portion coated with insulation, an armature termination, such as a commutator segment, and a support on which the termination is mounted. The termination has an integral terminal provided with a slot which straddles and grips the connector portion of the winding. The slot has an open end through which the winding is drawn after the termination has been mounted on the support. During an armature winding operation, two cutting edges cut through the insulation of the connector portion as it is drawn into the slot to establish electrical contact between the connector portion and the terminal.

Abstract: A direct current electric motor comprises a cylindrical casing of electrically conductive material, a stator magnet or magnets and a wound rotor, provided with a commutator, accommodated in the casing, an end cap in one end of the casing, and brush holding devices supported by the end cap. The brush holding devices have terminals which extend through the end cap for connection to an electric supply. A recess is provided in the end cap so as to extend between one of the terminals and the casing and a portion of the casing has been deformed so as to extend into the recess and make electrical contact with the one terminal.

Abstract: A solderless electrical connection between a wire and an electrical contact forming part of a permanent magnet motor. The motor includes a generally U-shaped motor frame that defines an open volume within which is mounted a plastic spacer or insert and a pair of opposed permanent magnets and that surround a rotating armature. One end of the armature terminates in a shaft which is received within a bushing that is mounted at the center of the planar central portion. The other end of the armature terminates in a shaft. Next to the armature and mounted on the shaft is a commutator. The shaft passes through a metallic bushing that is defined as part of a non-conductive insert which mates with the motor frame. Also mounted on the non-conductive member are a pair of brush assemblies. Each brush assembly basically consists of a pair of planar, opposed parallel legs that are joined together by a planar portion.