40 results about "Flux density distribution" patented technology

An apparatus for sensing a position of an object is provided that may include a magnet having a set of magnetic flux properties, the magnet mounted for movement about an axis relative to the object and a magnetic field-sensing device mounted in fixed relation to and spaced from the magnet, the magnetic field-sensing device calibrated to sense a change in at least one magnetic flux property in response to movement of the magnet relative to the object and generate a data signal indicative of a position of the object. In one aspect the magnet is configured to have a substantially diamond shaped cross section and the magnetic field-sensing device is calibrated to sense a change in flux density distribution in response to a change in an air gap defined between an exterior surface of the magnet and the magnetic field-sensing device.

A lens driving apparatus for a lens includes a voice coil motor. A coil position of a coil is detected. A table memory stores a correction factor for each one of plural values of the coil position according to flux density distribution. The correction factor is read from the table memory according to the detected coil position. A coil current is corrected by use of the correction factor for each coil position. The corrected coil current is caused to flow through the coil, with which the lens is moved together along an optical axis. Consequently, changes in a moving speed of the lens can be prevented.

A synchronous permanent magnet machine includes a permanent magnet arrangement for producing a magnetic field having a flux density distribution that is approximately sinusoidal. The permanent magnet arrangement includes a permanent magnet pole with both low and high energy-product magnets. The permanent magnet pole includes a low energy-product magnet and a high energy-product magnet which have different directions of magnetization, or a disposition of low / high energy-product magnets within the permanent magnet pole is asymmetric with respect to the central region of the permanent magnet pole.

A developing device includes a first magnet fixed inside a first developer bearing member and including a pair of first repulsion magnetic poles with the same polarity and disposed adjacent to each other, and a second magnet fixed inside a second developer bearing member and including a pair of second repulsion magnetic poles with the same polarity and disposed adjacent to each other. The first magnet has a magnetic flux density distribution of a normal component of the first developer bearing member in the circumferential direction of the first developer bearing member having only one minimal point between the pair of first repulsion magnetic poles, and the second magnet has a magnetic flux density distribution of a normal component of the second developer bearing member in the circumferential direction of the second developer bearing member having a plurality of minimal points between the pair of second repulsion magnetic poles.

The invention provides a method for finding an influence rule on torques and harmonic waves by negative sequence components in a steam-turbine generator and particularly relates to calculation of influences on the torques and the harmonic waves by a magnetic field generated by negative sequence current components, aiming at solving the problem that the heat stability of a motor is reduced, caused by the fact that a rotor of the large-size steam-turbine generator is restricted by the negative sequence components. The method comprises the following steps: step 1, establishing a steam-turbine generator model; step 2, analyzing the influences on the torques by the different negative sequence components; step 3, analyzing the influences on gap flux density harmonic waves by the changes of the different negative sequence components; and step 4, analyzing the influences on flux density distribution when the negative sequence components are changed. According to the method provided by the invention, simulating calculation can be carried out through the steam-turbine generator under the condition that the negative sequence current components are different, and the torques are calculated and analyzed under a negative sequence operating working condition; and regular changes of the gap flux density harmonic waves of the generator are concluded and analyzed.

The invention relates to an electric machine, particularly for a synchronous machine excited by a permanent magnet. The electric machine comprises a rotor arrangement (4) having buried permanent magnets (6) and a stator arrangement (2) having an inner recess (3) for rotationally movably receiving the rotor arrangement (4), the rotor arrangement (4) comprising a plurality of rotor segments (7), each having a pole shoe (10), the outer contour thereof corresponding to an arc contour having a contour radius, the contour radius being smaller than the radius of the rotor arrangement (4), thus forming a gap between two adjacent rotor segments (7), the at least one outer contour of one of the rotor segments (7) having an arc contour designed such that an air gap length ratio of the radial spacing between the inner recess (3) and the outer contour along a radial outer boundary of the corresponding rotor segment and the radial spacing between the inner recess and the outer contour along a radial center axis of the corresponding rotor segment (7) is optimized with regard to the distortion factor of the course of the flux density distribution of the pole shoe (10).

The invention discloses a near-field magnetic localization method for a circular ring magnet. The method includes the steps that a magnetic field distribution integral model of the circular ring magnet is built in a magnet coordinate system OXYZ, and then the magnetic field distribution integral model of the circular ring magnet is used for obtaining the magnetic flux density vector generated by the circular ring magnet at the space point on the plane YOZ; the value of the magnetic flux density vector generated at any space point around the circular ring magnet in the magnet coordinate system OXYZ is calculated; a magnetic doublet magnetic flux density distribution model is used for calculating respective initial values of six pose parameters of the circular ring magnet in a word coordinate system; the magnet coordinate system OXYZ is built in the word coordinate system according to the initial values of six pose parameters of the circular ring magnet in the word coordinate system, and the respective final values of the six pose parameters of the circular ring magnet in the word coordinate system are obtained. The near-field magnetic localization method has the advantages that location precision is high during near-field magnetic localization, and calculation complexity of magnetic flux density is reduced.

The invention discloses a non-uniform geometrical variational nodal method aiming at a reactor neutron diffusion equation. The method comprises the following steps: 1, establishing a functional containing a neutron conservation relationship inside the nodal block and flow continuity conditions on the nodal surface; 2, performing nodal discrete disposal by utilizing a finite element shape function in the x-y direction and a chip constant polynomial, and realizing non-uniform nodal geometrical and material description functions; 3, deducing to obtain a response matrix equation; and 4, solving the response matrix equation by utilizing a red-black scanning manner, and finally obtaining the neutron-flux density distribution in the whole non-uniform solving area. According to the method disclosed by the invention, the non-uniform lattice-cell structure of a nuclear reactor can be finely described; and according to the method, the nodal internal fine geometrical structure is processed based on the variational nodal method by adopting an isoparametric finite element, and then the non-uniform geometrical neutron diffusion equation is solved.

The invention provides a method for finding an influence rule on torques and harmonic waves by negative sequence components in a steam-turbine generator and particularly relates to calculation of influences on the torques and the harmonic waves by a magnetic field generated by negative sequence current components, aiming at solving the problem that the heat stability of a motor is reduced, caused by the fact that a rotor of the large-size steam-turbine generator is restricted by the negative sequence components. The method comprises the following steps: step 1, establishing a steam-turbine generator model; step 2, analyzing the influences on the torques by the different negative sequence components; step 3, analyzing the influences on gap flux density harmonic waves by the changes of the different negative sequence components; and step 4, analyzing the influences on flux density distribution when the negative sequence components are changed. According to the method provided by the invention, simulating calculation can be carried out through the steam-turbine generator under the condition that the negative sequence current components are different, and the torques are calculated and analyzed under a negative sequence operating working condition; and regular changes of the gap flux density harmonic waves of the generator are concluded and analyzed.

The invention discloses a light spot thermal flux density distribution test system. The light spot thermal flux density distribution test system comprises a ceramic installation base, a plurality of temperature sensors, an input and output module, a data processing module, a data display module, a rear end cover plate, a top plate, a bottom plate, a middle supporting plate, two side plates, a speed reducer and a drive motor, wherein one end of the ceramic installation base is fixed to the position of a circular hole in a front end cover plate, the other end of the ceramic installation base is connected with a rotating shaft, the temperature sensors are distributed on the test installation face of the ceramic installation base, the rear end cover plate is provided with the speed reducer, a circular hole used for allowing the rotating shaft to penetrate through is formed in the middle of the middle supporting plate, the other end of the rotating shaft is connected with the speed reducer, the drive motor is arranged on the speed reducer, the drive motor drives the speed reducer to rotate, and rotation is delivered to the rotating shaft so that the ceramic installation base can be driven to rotate. The light spot thermal flux density distribution test system can test whether the thermal flux density distribution of light spots on a whole section is even or not, and the phenomenon that when light spot thermal flux density distribution is not even due to condenser system errors, a hot end part of a thermal absorber is burnt, and even a working medium leaks or explodes is avoided.