Abstract: The present invention refers to an electric motor comprising a stator with an internal permanent magnet and a tubular magnetic return sleeve surrounding said permanent magnet whereby an annular air gap is formed therebetween, said magnetic return sleeve being held at its axial and radial positions relative to said permanent magnet by a frame of plastic material injected around these two components and being connected to said permanent magnet by said plastic frame. The present invention aims at improving the manner in which the two structural components are attached to and positioned on one another.

Abstract: A method and circuit is disclosed for soft-commutation of a direct current (DC) motor. An attenuation circuit is connected through auxiliary brushes A, A', B and B' to the commutator (16) to drain circuit from successive armature coils (15) before the main brushes (27, 28) disconnects from each of the coils (15). This prevents the spark generation that normally occurs in conventional DC motors. The attenuation circuit may also be connected before energization of the coil (15) for a soft turning on operation.

Abstract: A varistor is mounted to a commutator using intermediary springs which are soldered to the terminals of the varistor. The springs engage the tangs of the commutator without soldering to physically and electrically connect the varistor to the commutator.

Abstract: A rotor for an induction motor of the squirrel cage type wherein the rotor bars are exposed to a resilient anti-sparking compound in the rotor slots of the machine. The rotor bars are provided with a longitudinal slot to permit the insertion of the anti-sparking compound after assembly of the squirrel cage rotor. Alternatively, the laminations may be shaped to produce a longitudinal groove in the rotor bar slot to permit the insertion of the anti-sparking compound in the groove so produced. Of course, both the rotor bar and the rotor slot may both be provided with complimentary slots adjacent one another in which the anti-sparking compound may be injected.

Abstract: A commutator has a base, a plurality of commutator segments mounted on the base and a noise suppression element. The noise suppression element is electrically connected to the segments by a connecting element, in the form of an elastomeric ring having conductive portions, which is compressed between the noise suppression element and the commutator segments, or terminals associated with the commutator segments, to avoid the need to solder the noise suppression element to the segments.

Abstract: A rotor for an electric motor comprises a shaft, a commutator fitted to the shaft and connected to a winding wound around poles of an armature core, and a noise suppressor. The noise suppressor 40 has chip capacitors 44 connected to terminal portions 38 of commutator segments 32. The capacitors 44 have a common terminal 45 connected together to form a star connection via a ring formed from a conductive layer 42 on a board 41 or from resilient wire. The capacitors 44 may be soldered to the wire ring and to the commutator segments or may be held in recesses formed in the base of the commutator in direct contact with the commutator segments under resilient urgings of the ring to form a solderless connection. It is particularly suited to rotors using mechanical connection type commutators to form solder-free rotors.

Abstract: An apparatus reducing capacitive coupling between the stator and the rotor of an electromagnetic machine. The apparatus includes an electrically connective shield positionable between the stator and the rotor, the shield electrically separated from both the stator windings and the rotor when so positioned. A grounder electrically connects the shielder to ground thus substantially reducing capacitive coupling between the stator and the rotor.

Abstract: A grounding system for an AC or DC motor or other rotating apparatus employs a conductive brush in resilient contact with a contamination free conductive member removably secured onto a rotating part such as a motor shaft or tachometer shaft. The contacting surface is preferably formed of brass and is shielded from contamination from motor bearings and the like, for reliably shunting the shaft to the frame of the machine so as to avoid high voltage transients across bearings as would otherwise result in bearing damage or destruction.

Abstract: The present invention teaches an improved brush holder assembly. The holder has a first terminal wire and comprises a support plate and a tower attached thereto for securing the first terminal wire. The tower comprises a body and an end. The body comprises an interior passageway with a number of ribs for securably positioning the first terminal wire within the body and a groove for securing the first terminal wire within the tower. The tower's end functionally crimps the first terminal wire and has a plurality of support members for securably positioning the crimped first terminal wire within a mouth of the end. A coil spring forming an inductor is also incorporated for mechanically biasing a brush and for filtering out electromagnetic interference (EMI).

Abstract: A miniature motor comprising a case made of a metallic material, formed into a bottomed hollow tubular shape and having a permanent magnet fixedly fitted to the inner circumferential surface thereof, a rotor having an armature facing the permanent magnet and a commutator, and a case cap fitted to an open end of the case, and having brushes for making sliding contact with the commutator and input terminals electrically connected to the brushes; the rotor being rotatably supported by bearings provided on the bottom of the case and the case cap, in which an internal space defined by the case and the case cap is filled with an atmosphere of a polymer having a weight-average molecular weight of 50-5000.

Abstract: A varistor disk assembly for mounting to a commutator base comprising a non-conductive retaining ring, a conductive member, and a varistor disk interposed between the commutator base and the distal end of the retaining ring. The retaining ring has an axial bore therethrough providing a friction fit with the motor shaft on which the commutator is mounted. A tolerance absorbing member can be interposed between the varistor disk and the retaining ring. The conductive member conducts current through its thickness from the commutator base to the varistor disk, but does not conduct current between adjacent commutator segments. To orient the varistor disk to the commutator, the proximal end of the retaining ring can have at least one planar side formed in its periphery for alignment with one of the commutator segments, while the distal end of the retaining ring also has formed in its periphery a planar side, and the varistor disk is provided with a complementary planar side in its inner diameter.

Abstract: An explosion-proof type rotating electrical machine having excellent cooling and brush powder discharge capabilities. A drive shaft of a rotor is provided with slip rings for supplying current to a field coil, which is energized through brushes capable of activating the field coil by contacting with the slip rings. The brush compartment incorporated with the brushes and slip rings and the outside of the rotating electrical machine are connected with each other through an air suction path, the brush compartment and an inside space of the rotating electrical machine are connected with each other through an air blowing path, in which a flame stifling wire net is provided.

Abstract: A miniature motor comprising a housing made of a metallic material, formed into a bottomed hollow tubular shape and having a permanent magnet fixedly fitted to the inner circumferential surface thereof, a rotor consisting of an armature facing the permanent magnet and a commutator, an end cap engaged with an open end of the housing, and having brushes making sliding contact with the commutator and a pair of terminals electrically connected to the brushes; the rotor being rotatably supported by bearings provided on the bottom part of the housing and the end cap, in which a flat groove including a plane parallel to the axial line of the motor and opening toward the housing is provided on the end cap; the terminals being disposed to face the side of the groove, a chip laminated capacitor and a spring made of an electrically conductive material and formed into a substantially U shape in planar projection being disposed in the groove so as to come into contact with each other and also with the terminals.

Abstract: A miniature motor comprising a case made of a metallic material, formed into a bottomed hollow cylindrical shape and having permanent magnets on the inner circumferential surface thereof, a rotor consisting of an armature facing the permanent magnets and a commutator, and a case cap fitted to an open end of the case and having brushes making sliding contact with the commutator and input terminals electrically connected to the brushes; the rotor being rotatably supported by bearings provided on the bottom of the case and the case cap, in which an internal space defined by the case and the case cap is filled with an atmosphere of one or more than two types of polymethacrylate, polyacrylate, polyisobutylene, low molecular weight polyethylene, low molecular weight polypropylene, ethylene-propylene copolymer, polyvinyl acetate, and polybutene.

Abstract: A connecting cover for a pump housing of an electric fuel pump, which pump housing accommodates a direct current motor has a cover body having a cover axis and brush guides arranged radially with respect to the cover axis and provided for guiding commutator brushes, connecting plugs projecting from the outer side of the cover body, connecting lances which connect the connecting plugs electrically with the brushes, a screening unit for screening spark interferences of the commutator brushes. The screening unit includes at least one condensor provided with two connecting wires. The body has a bottom with axially projecting ribs which form a pocket for receiving the capacitor. The capacitor has a first connecting wire abutting against one of the brush guides and a second connecting wire for contacting the pump housing or a pole pipe of the direct current motor and extending outwardly on a periphery of the body.

Abstract: An electrical motor includes a ground brush connected to ground, first and second supply brushes connected to first and second supply lines and adapted to cause the motor to rotate at first and second speeds, and an interference suppression device comprising a common core, a first coil connected in series between the first supply brush and the first supply line and a second coil connected in series between the second supply brush and the second supply line. The space required by the device in the motor casing is less than with the conventional arrangement of two individual chokes and can provide improved noise suppression due to magnetic coupling between the two coils.

Abstract: A miniature motor including a housing formed into a bottomed hollow cylindrical shape, on the inner circumferential surface of which a permanent magnet is fixedly fitted; A rotor is provided having an armature, a spark-quenching element and a commutator. An end bracket is provided having brushes fitted to the open end of the housing and making sliding contact with the commutator. Input terminals are electrically connected to the brushes; The rotor is rotatably supported by bearings provided on the housing and the end bracket, in which the spark-quenching element is formed by a laminated ceramic capacitor formed into a ring shape, having on the outer surface thereof the same number of electrodes as the number of poles of the armature; The electrostatic capacity of the capacitor is more than 1 .mu.F.

Abstract: A commutator has a central support supporting a plurality of conductive segments separated by a plurality of insulative segments. In addition to providing an insulative function between the conductive segments, the dielectric constant, the area, and the thickness of the insulative segments are chosen so that they provide a capacitive effect, which capacitive effect suppresses current peaks during operation of the commutator. Preferably, the dielectric constant is greater than 10. The central support may include a metal shaft and an insulating ring, which insulating ring is preferably of material with a lower dielectric constant thereby to suppress-shorting between the shaft and the conductive segments. It is particularly advantageous if the conductive and insulative segments are of ceramics material since this provides good wear resistance. In further alternatives, capacitors are formed between the conductive segments by rings or other bodies of insulative materials of a suitably high dielectric constant.

Abstract: An adjustable-brush motor incorporates an integral stepping motor or servo to electromechanically adjust the commutating angle of the primary brushes by input of an electrical signal, and to maintain a predetermined commutating angle in the absence of an electrical signal. The adjustment is in accordance with load changes to reduce sparking, to upgrade the electromechanical conversion efficiency of the motor, and to reverse the direction of rotation.

Abstract: In a fractional horsepower PMDC motor a varistor comprises an annular ring of varistor material having a heat sink bonded to one face. The heat sink includes a plurality of fan blades and is attached to a commutator of the motor. The heat sink increases the thermal capacity of the varistor to resist overheating under stall conditions and improves heat dissipation when the motor is running.

Abstract: The trailing edge of a carbon brush for commutating electric machines has a notch flanked by an ear on either side. The brush can include one or more wafers. The angular thickness of the trailing brush wafer at the notch is such that the brush does not touch more than n commutator contacts at a time. However, the brush wafer is thick enough at the ears to touch n+1commutator contacts at a time. The relatively high resistance of the ears improves commutation.

Abstract: A commutator arrangement includes a commutator member rotatably mounted on a support and including a plurality of circumferentially adjacent contact pads that are mechanically connected with one another and electrically separated from each other by respective intervening gaps, and a number of commutator brushes that are mounted on the support for only substantially radial movements toward and away from the commutator member and are biased toward the latter to establish contact between their respective contact surfaces and those of the pads. The lateral edges bounding one kind of these contact surfaces circumferentially deviate from those delimiting the other contact surface kind over at least a part of their courses such that different portions of such lateral edges are juxtaposed with their counterparts at different times during the relative rotation of the commutator member.

Abstract: A method and device for detecting a partial discharge pulse in a high voltage conductor in the stator of a motor, turbine generator or the like, comprising a conductive plate having an insulated face, an insulated signal conductor spanning the insulated face of the plate, and means for transmitting an electrical pulse produced in the signal conductor to recording means for determining the location and severity of partial discharge activity within the high voltage insulation of the conductor.

Abstract: A resistor ring, typically a varistor, is clamped in intimate contact with terminals of a commutator using a clip-on plastic clamp having a plurality of shock-absorbing spring fingers, thus avoiding the application of heat which could damage the resistor ring.

Abstract: A deflection detection device for monitoring deflection of a diaphragm having a radius r has a first plurality of optical fibers having fiber ends concentrically disposed about the center of the diaphragm at a radius r.sub.1 where r.sub.1 is less than r. A second plurality of optical fibers having fiber ends concentrically disposed about the center of the diaphragm forms a circle having a radius r.sub.2 where r is greater than r.sub.2 is greater than r.sub.1. A third plurality of optical fibers having fiber ends concentrically disposed about the center of the diaphragm forms a circle having a radius r.sub.3 where r is greater than r.sub.3 is greater than r.sub.2. The ends of the first and third plurality of optical fibers are light capturing and the ends of the second plurality of optical fibers are light emitting.

Abstract: A current-collecting brush apparatus is disclosed in which brushes are held slidably on a brush holder and pressed against a rotor by a brush-pressing spring. Pigtails connected to supply current to the brushes comprise a plurality of spiral conductors in parallel which are connected by being coiled in mutual opposite directions to offset the magnetic fluxes generated therein.

Abstract: A spark-protected alternator has an external cavity on an end plate of the alternator housing with commutating (slip) rings on an alternator shaft extension and mating metal brushes positioned within the external cavity. The external cavity is effectively sealed from ambient atmosphere surrounding the alternator, to provide protection from sparks generated between the brushes and commutating rings wherein a minimum area of the housing end plate is utilized. Integral extensions of the end plate form side walls of the external cavity that partially radially surround the shaft extension and commutating rings. A brush holder in which the brushes are attached has projections which mate with slots in the side walls to radially close the external cavity, and an end cap (including a gasket) closes an open end of the external cavity, while the end plate effectively closes the other end of the external cavity.

Abstract: In electrical machines with commutators, installing diodes and controlled rectifiers right into the electromechanical structure of armatureseliminates sparking of the commutators, and alsoallows the design of AC-fed motors having the characteristics of DC motors, including the capability to return power to the AC line while being overdriven.Use of controlled rectifiers permits to eliminate the mechanical commutator itself; the controlled rectifiers assume the commutation process utilized by the invention, wherein there is a cooperation between rectifiers and armature coils undergoing commutation.

Abstract: A cylindrical, ironless, self-supporting rotor coil for use in an electrical dc-machine is disclosed. The coil is formed by at least one layer of wire, the wire having a conductive core, an insulating layer surrounding that core and an outer layer comprising a supporting material capable of being softened and subsequently solidified to make the coil self-supporting. The outer layer of the wire is at least in part electrically conductive in order to reduce the production of sparks in the commutator of the dc-machine.

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: A small electric motor having an insulating cylinder fixedly fitted to a rotating shaft of a motor rotor, a plurality of commutator segments disposed at equal spacing in the angular positional direction of the insulating cylinder and brushes for making sliding contact with the cummutator segments. Each of the commutator segments has a commutator terminal formed by bending an end of the segment and led out for external connection. The insulating cylinder has an enlarged diameter portion, on which adhesive reservoirs are provided. An electrically conductive adhesive is injected into the reservoirs and deposited in such a manner as to bridge the adjoining commutator segments.

Abstract: A brush having at least a portion thereof adjacent the trailing end made up of a plurality of individually insulated strands of highly conductive material.

Abstract: An armature winding distribution for an electric motor divides each armature coil into first and second coil sub-sections inter-distributed with one another so that the first and second coil sub-sections of an armature coil undergoing commutation at one of the brushes are coupled, respectively, to the coil sub-section of an armature coil about to undergo commutation by the other brush and the coil sub-section of another armature coil having just completed commutation by the other brush. Excess energy in the armature coil undergoing commutation by the first-mentioned brush is transferred to a coil sub-section of the coil just about to undergo commutation and/or a coil sub-section of the coil having just completed commutation by the other of the brushes. The armature winding distribution improves commutation and substantially reduces brush sparking and the generation of electromagnetic interference (EMI) across a wide range of frequencies.

Abstract: The permanent magnet fields encircling the armature of a direct current motor are encircled by a pair of radially spaced cylindrical metal members separated by a cylindrical dielectric member. One of the metal members and one of the brushes that engages the commutator of the motor are grounded. The other brush and the other cylindrical metal member are connected to a direct current power supply, whereby a capacitor is formed by the three cylindrical members for suppressing radio frequency noise generated by sparking of the brushes at the commutator.

Abstract: A small electric motor having a plurality of commutator segments disposed at equal intervals in the angular positional direction on an insulating cylinder fixedly fitted to the rotating shaft of a motor rotor, and brushes for making electrical contact with the commutator segments, wherein reservoirs for holding an electrically conductive mixture are provided by boring the insulating cylinder in such a manner that the reservoirs extend to the adjoining commutator segments, the electrically conductive mixture being injected into the reservoirs so that the mixture is deposited in such a manner that the mixture bridges each commutator segments and covers the intervening portions between the commutator segments, the reservoirs being disposed in the locations at which the commutator segments and the brushes do not contact.

Abstract: Commutator segment shapes are derived, in relation to machine parameters, for which the current density over the trailing edge of the brush is maintained constant, to prevent sparking. The preferred shape is such that the area of contact between the segment and a linear brush increases initially in a single step to half the total area and subsequently increases progressively more slowly; in an alternative shape, the subsequent rate of increase is linear. Suitable brushes to maintain uniform contact in crossing segment boundaries are preferably of the carbon-fibre type.

Abstract: A direct-current micromotor is disclosed which comprises a rotor bearing a motor winding, the rotor being arranged for rotation between a core part and a mantle part of a stator structure. The core part comprises a permanent magnet and the mantle part is made of magnetically conductive material. The motor winding is fed through a commutator comprising a collector and associated brushes. At least a part of the surfaces of the stator facing the rotor winding are provided with an electrically conductive coating to reduce the height of the voltage peaks occuring during the commutation.