44results about How to "Reduce shaft voltage" patented technology

This invention reduces the shaft voltage of an axial-air-gap dynamo-electric machine while ensuring high output and high efficiency. Said axial-air-gap dynamo-electric machine comprises the following: a stator comprising a plurality of stator cores, each of which comprises a core and a coil, arranged in a circle around a shaft; a housing, the inside surface of which faces the stator radially; and at least one rotor, the surface of which faces the surface of the stator with a prescribed air gap interposed therebetween in the radial direction of the shaft. The rotor has, on the outside thereof, a conductive section comprising a conductive member. This axial-air-gap dynamo-electric machine has a first region where the inside surface of the housing faces the aforementioned conductive section radially and a second region, closer to the stator than the first region is, that extends to the coil side surfaces that face the rotor. The proportion of connecting wires in the second region is higher than in the first region.

A motor includes: a stator molded integrally with an insulating resin having a fixing member including a stator iron core and a winding wound thereon; a rotor arranged to face the stator about a shaft; a bearing rotatably supporting the shaft; a bracket fixing the bearing; and a drive circuit substrate having a drive circuit mounted thereon for driving the winding. The stator iron core is electrically connected to a ground serving as a reference point of a zero potential on the drive circuit substrate through a conductive member.

Provided is an electric motor driven by an inverter of PWM method, and devised to retard electrolytic corrosion in a bearing. A rotating body of a rotor comprises an outer iron core configuring an outer peripheral portion of the rotating body, an inner iron core configuring an inner peripheral portion connected to a shaft, a dielectric layer disposed between the outer iron core and the inner iron core, a plurality of insertion holes penetrating the outer iron core in the axial direction, and permanent magnets inserted individually in the plurality of insertion holes. It thus becomes possible to increase impedance of the rotor side (inner ring side of bearing) to approximate it to impedance of the stator side (outer ring side of the bearing) to thereby bring high frequency potentials balanced between the inner ring side and the outer ring side of the bearing, so as to provide the electric motor that retards electrolytic corrosion liable to occur in the bearing, and an electric device equipped with the same.

An electric motor includes a stator that has a stator winding wound on a stator iron core; a rotor having a rotating body with a rotating shaft in the center; a bearing for journaling the rotating shaft; and two conductive brackets for fixing the bearing. The rotating body holds a magnet such that the magnet faces the stator, and is fastened to the rotating shaft penetrating through the center of the rotating body. In the rotating body, a dielectric layer is formed between the rotating shaft and the outer circumference of the rotating body. The dielectric layer has a polygonal shape with the rotating shaft in the center. An electric device includes the thus configured electric motor.

To protect the bearings, lubricant and seals of a refrigerant compressor, the compressor includes one or more inductors for mitigating a high frequency common mode current that produces a high frequency shaft voltage. Each inductor is a ring of magnetic material encircling three insulated cables that convey three-phase power from an adjustable frequency drive to the compressor's motor. Without the inductors, the high frequency shaft voltage can become damagingly high due to the length of a cast iron housing that can be particularly long if the housing contains both a motor and several centrifugal impellers. The high frequency shaft voltage is just one component of a composite adverse shaft voltage. Another component, known as an operationally induced shaft voltage, can be reduced by a grounding contact, so instead of using just an inductor or just a contact, both can be used to provide a total solution to the problem.

To ensure ready assembly of a stator and reliably reduce the shaft voltage in an axial air gap rotating electric machine, an axial air gap rotating electric machine has a circular ring-shaped stator formed by a plurality of stator cores arranged about a rotational axis direction in a ring shape. Each stator core comprises a tubular bobbin and a coil, with the tubular bobbin having an iron core inserted into a bobbin inner tubular portion substantially matching the peripheral shape of the iron core. The axial air gap rotating electric machine has a first conductive member having a horizontal portion and a vertical portion contacting the end surface of the bobbin opening portion. The horizontal portion contacts parts of the iron core outer peripheral surface and the inner peripheral surface of the bobbin inner tubular portion, and the vertical portion is conductively connected to the inner circumferential housing surface.

The invention discloses a triple shielding flame retardant type single core nuclear power cable which comprises an outer insulating sleeve, a first shielding layer, an inner insulating sleeve, a second shielding layer, a bus insulating net belt, a sub-line and a sub-line filling-pressing strip, wherein the sub-line comprises a sub-line shielding layer, a sub-line insulating net belt, a sub-line sheath, a heat insulating film and a lead core, and the exterior of the lead core is sequentially provided with the heat insulating film, the sub-line sheath, the sub-line insulating net-belt and the sub-line shielding layer. Because three lead cores are respectively wrapped by the sub-line sheath, the sub-line insulating net belt and the sub-line shielding layer, three sub-lines are filled and pressed by the filling-pressing strip and are glued firmly into a cable, each lead core is subjected to three passes of metallic shielding, the power cable can not be interfered by an external electric field and an external magnetic field in the power transmission process, an electromagnetic field generated by the power cable is also shielded, and the electricity and control system of an adjacent distribution circuit can not be interfered. By means of the special arrangement structure of the triple shielding flame retardant type single core nuclear power cable, a shaft voltage generated by an electric appliance in service in a frequency conversion loop is reduced, and the practice safety of the electric appliance is protected.

The invention provides a brushless motor and electrical equipment. The brushless motor comprises a casing, a stator and a rotor, the stator comprises a stator core and a winding, the rotor comprises arotor core and a rotating shaft, corresponding positions of two ends of the rotating shaft are respectively sleeved with a bearing, and two ends of the casing are respectively provided with a bearingbracket. The brushless motor further comprises a conducting strip used for adjusting capacitive reactance between the stator iron core and the bearing bracket, the conducting strip is attached to theouter circumferential face of the casing, and in the radial direction of the casing, the conducting strip and the stator iron core have at least part of the opposite area. The conducting strip is attached to the outer peripheral surface of the casing, so that the conducting strip and the stator core have opposite areas, coupling capacitance is formed between the stator core and the conducting strip, the bearing bracket is located at the end of the casing, equivalent capacitance between the stator core and the bearing bracket is adjusted, potential between the bearing outer ring and the bearing inner ring is balanced, and the service life of the motor is prolonged. The potential between the bearing outer ring and the bearing inner ring is close, so that the shaft voltage is reduced, and the bearing is prevented from generating electric corrosion.

The invention relates to a motor ground connection structure, in particular to a ground connection structure for reducing the shaft voltage of a double-fed wind generator, and belongs to the technical field of wind generators. The ground connection structure comprises a shaft extension terminating shaft carbon brush, a machine base outer shell and a non-shaft extension terminating shaft carbon brush all of which are sequentially connected through an electric connecting line. The ground connection structure is low in cost, reasonable in structure and obvious in effect, a method for reducing the shaft voltage is added, the ground connection structure is suitable for being applied in a wind power system with requirements for zero maintenance and high reliability, and the reliability of wind electricity operation is improved.

The invention discloses a structure for reducing shaft voltage of a PWM inverter driving type plastic package motor, which relates to the field of motors. In the existing PWM inverter driving type plastic package motor, a high-frequency switch of a power element can cause change of common-mode voltage and parasitic capacitance at each position in the motor, so that a potential difference is generated between an inner ring and an outer ring of a bearing, an oil film of bearing lubricating grease is easily damaged, the bearing is damaged by electrocorrosion, and electrocorrosion generated by theinner ring, the outer ring and a ball is always a key factor influencing the service life of the motor. According to the structure disclosed in the invention, a front end cover and a rear end cover are connected through a conductive piece to realize equipotential, and a capacitor is connected between the conductive piece and a stator core. Effective conduction among the front end cover, the rearend cover and the stator iron core is conveniently realized, the equipotential is formed, the capacitor is arranged between the end cover and the stator core, a proper amount of capacitance is added,and finally, the external induction capacitance of the inner ring and the outer ring of the bearing is balanced, so that the shaft voltage is effectively reduced, the electrocorrosion risk of the bearing is avoided, the service life of the motor is prolonged, and the reliability is improved.

The invention provides a brushless motor and electrical equipment, the brushless motor comprises a casing, a stator and a rotor, the stator comprises a stator iron core and a winding, the rotor comprises a rotor core and a rotating shaft, the rotating shaft is sleeved with bearings, two ends of the casing are each provided with a bearing bracket for fixing the two bearings, a first conducting strip and a second conducting strip are arranged between at least one bearing bracket and the stator iron core, the first conducting strip and the second conducting strip are oppositely arranged side by side at intervals, the first conducting strip is electrically connected with the stator iron core, and the second conducting strip is electrically connected with the adjacent bearing brackets. The brushless motor is internally provided with the first conducting strip and the second conducting strip which are electrically connected with the stator core and the bearing brackets respectively, and thefirst conducting strip and the second conducting strip are arranged side by side at an interval, so that the first conducting strip and the second conducting strip can be matched to adjust the capacitive reactance between the stator core and the bearing brackets, the potential of the bearing outer ring is close to that of the bearing inner ring, shaft voltage is reduced, and electric corrosion ofthe bearing is avoided.

The invention relates to a triple shielding flame-retardant type power cable special for nuclear power, which comprises an outer insulating sleeve, a first shielding layer, an inner insulating sleeve, a second shielding layer, bus insulating grid belts, sub-wires and sub-wire filling press strips, wherein the sub-wires comprise a sub-wire shielding layer, a sub-wire insulating grid belt, a sub-wire protective sleeve, a heat insulating membrane and wire cores; and the heat insulating membrane, the sub-wire protective sleeve, the sub-wire insulating grid belt and the sub-wire shielding layer are sequentially arranged outside the wire cores. The three wire cores are wrapped by the heat insulating membrane, the sub-wire protecting sleeve, the sub-wire insulating grid belt and the sub-wire shielding layer respectively, the three sub-wires are filled and pressed through the sub-wire filling press strips and firmly glued into a cable and each wire core is shielded through three paths of metal, thus, outside electric fields and magnetic fields cannot interfere with the power cable in the transmission course of electric power; the electric and magnetic fields generated by the electric power are shielded to prevent the interference on an electric and control system of the adjacent distribution circuits; and the special ranking structure of the power cable reduces the shaft voltage generated by electric equipment in a frequency conversion circuit in the operation course and protects the practical safety of the electric equipment.

The invention belongs to the technical field of motors, and relates to a motor and electrical equipment with the motor. A traditional integrated bearing bracket is separated into a stator bracket partand a bearing supporting part, a bracket insulating layer is arranged between the stator bracket part and the bearing supporting part, and equivalently, an insulating layer capacitor is added betweenthe stator bracket part and the bearing supporting part. Due to the arrangement of the bracket insulating layer, the equivalent capacitance of the stator side can be greatly reduced. In the loop of the high-frequency circuit, the shaft voltage is the voltage division of the two ends of the bearing capacitor, and the equivalent capacitor of the stator side is equivalently connected to the bearingouter ring side of the bearing capacitor in series. Therefore, the equivalent capacitance of the stator side is reduced through the arrangement of the bracket insulating layer, so that the two ends ofthe bearing capacitor obtain smaller voltage division, i.e., the shaft voltage is reduced. An electrode structure is arranged to reduce shaft voltage and shaft current. The risk of bearing electrocorrosion is reduced. For a motor which is large in power and adopts a large metal shell to improve the installation strength and guarantee heat dissipation, the risk of electrocorrosion damage to a motor bearing can be reduced.

The invention provides a brushless motor and electrical equipment, the brushless motor comprises a casing, a stator and a rotor, the stator comprises a stator iron core and a winding, the rotor comprises a rotor core and a rotating shaft, a bearing is sleeved on the rotating shaft, two ends of the casing are provided with bearing brackets respectively, each bearing bracket is insulated from the stator iron core, a conducting strip used for balancing the potentials of the bearing inner ring and the bearing outer ring in a matched mode is arranged between at least one bearing bracket and the stator iron core, and the conducting strip is electrically connected with the stator iron core and one adjacent bearing bracket. According to the brushless motor, the conducting strip is arranged betweenthe stator iron core and the bearing brackets, and the conducting strip is electrically connected with one of the stator iron core and the adjacent bearing bracket, so that the conducting strip is incapacitance connection with the stator iron core or the adjacent bearing bracket, the capacitive reactance between the stator iron core and the bearing bracket is adjusted, the potentials of the bearing outer ring and the bearing inner ring are balanced, the potentials of the bearing outer ring and the bearing inner ring are close, the shaft voltage is reduced, and the bearing is prevented from electric corrosion.

The invention provides a brushless motor and electrical equipment, the brushless motor comprises a casing, a stator and a rotor, the stator comprises a stator iron core and a winding, the rotor comprises a rotor core and a rotating shaft, the rotating shaft is sleeved with a bearing, two ends of the casing are each provided with a bearing bracket, conducting strips are arranged on the peripheral side of the stator iron core at intervals, the conducting strips and the stator iron core have at least a part of opposite area, the conducting strips and at least one bearing bracket are arranged in an insulating mode, an electric strip is attached to the outer surface of each bearing bracket, a dielectric layer is arranged between the electric strip and the corresponding bearing bracket, and theelectric strips are electrically connected with the conducting strips. The conducting strips are arranged on the peripheral side of a stator iron core at intervals, so that coupling capacitance is formed between the stator iron core and the conducting strips; the electric strips are arranged on the bearing brackets, so that the capacitor is formed between the electric strips and the bearing brackets, and the electric strips are electrically connected with the conducting strips, thereby adjusting the capacitive reactance between the bearing brackets and the stator iron core, reducing the potential difference between an inner ring and an outer ring of a bearing, reducing the shaft voltage and avoiding electric corrosion.

The invention discloses a motor rotor which comprises an inner iron core and an outer iron core. The inner iron core and the outer iron core are arranged concentrically and are fixed through an insulation frame. The motor rotor is characterized in that the thickness h of the inner iron core and the thickness H of the outer iron core satisfy the relation that h : H is larger than or equal to 0.5 and smaller than 1, and the distance between a plane where either end face of the inner iron core is placed and a plane where an end face on the same side of the outer iron core is placed is 0.5 H-0.5 h. According to the designing scheme that the thickness of the inner iron core is smaller than the thickness of the outer iron core, shaft voltage can be lowered, and poor motor electric corrosion is reduced.

Provided is a scroll compressor capable of reducing a shaft voltage and achieving space savings for the entire apparatus. A scroll compressor 100 includes a rotor 32 that is stored in a motor casing 14; a stator 31 that is stored in the motor casing 14, and drives the rotor 32 to rotate; a rotary shaft 12 that is held by bearings 33 and 34, and rotates integrally with the rotor 32; an end bracket 16 through which one end portion of the rotary shaft 12 passes, and which seals the motor casing 14; an orbiting scroll 44 that supports the other end portion of the rotary shaft 12, and orbits as the rotary shaft 12 rotates; a fixed scroll 43 that is disposed facing the orbiting scroll 44; a suction type cooling fan 13 which is fixed to one end portion of the rotary shaft 12 while being apart by a clearance from the end bracket 16, and which suctions outside air through a suction port provided in an end surface 132A of a fan cover 132, and generates cooling wind for cooling the fixed scroll 43 or the orbiting scroll 44 in the fan cover 132, as a rotary vane 131 accommodated in the fan cover 132 rotates; and a discharge brush 60 which is fixed to the end bracket 16 facing the cooling fan 13, and one end of which is in contact with the rotary shaft 12.