79 results about "Electromagnetic design" patented technology

The invention discloses a solving method electromagnetic design used for a surface-mounted permanent magnet motor. The solving method comprises the following steps: (1) based on an improved subdomainmethod, establishing a vector magnetic potential expression of a permanent magnet, an air gap and a stator slot, and obtaining current magnetic field distribution of three subdomains according to thevector magnetic potential expression, wherein an equivalent current sheet is added into the stator slot as a boundary condition, the vector magnetic potential expression of the stator slot is relatedto the current density of the equivalent current sheet; (2) according to the obtained current magnetic field distribution, using a magnetic circuit method to solve and obtain the magnetic voltage dropof each part of a stator core, and converting the magnetic voltage drop into the current density of the equivalent current sheet inside the stator slot; (3) through mutual iteration of the improved subdomain method and the magnetic circuit method, solving the magnetic field distribution of the three subdomains; and (4) calculating permanent magnet motor magnetic flux linkage, counter electromotive force and cogging torque. By using the solving method, the magnetic field distribution of the motor and the electromagnetic performance of the motor under the condition that a saturation effect is considered can be calculated accurately, and optimal opinions are provided for motor design.

The invention discloses a three-dimensional forming manufacturing system and method for a wave absorbing material. The method comprises the steps that 1, a resin substrate shaped wave absorbing material is prepared; 2, the structure inside the resin substrate shaped wave absorbing material is formed orderly; 3, the structure inside wave absorbing micro powder is manufactured orderly; 4, a hot melt plastic based wave absorbing material is manufactured in a three-dimensional forming mode; and 5, the hot melt plastic based wave absorbing material is controlled by a magnetic field. The invention further provides the three-dimensional forming manufacturing system for the wave absorbing material. The three-dimensional forming manufacturing system comprises a resin substrate shaped wave absorbing particle forming manufacturing module, an orderly distributed wave absorbing microsphere preparation module, a pulse type pressurization and temperature control printing module and a three-dimensional forming three-coordinate mechanism module. According to the three-dimensional forming manufacturing system and method for the wave absorbing material, the electromagnetic design and manufacturing of the wave absorbing material are combined, preparation and controllable manufacturing of the inner structure of the wave absorbing material of a complex structure are achieved, the designability of the wave absorbing material is improved, and the wave absorbing performance of the wave absorbing material is improved.

The invention relates to the field of transformer electromagnetic design scheme evaluation, in particular to a cloud ideal solution evaluation method for a transformer electromagnetic design scheme. The method comprises the steps of screening evaluation indexes, collecting and arranging data, and constructing a cloud model decision matrix; according to the cloud model decision matrix, generating a deterministic decision matrix; determining a weight of a cloud model; according to the weight of the cloud model, generating a deterministic weight; determining positive ideal cloud and negative ideal cloud; calculating a comprehensive determination degree of each scheme for the positive and negative ideal cloud; calculating a close degree of each scheme; and according to the close degrees, sorting to-be-evaluated schemes. According to the method, a technique for order preference by similarity to ideal solution (TOPSIS) is improved by utilizing the randomness and fuzziness of a cloud theory, the shortcomings of a conventional TOPSIS for calculating the close degree by utilizing a Euclidean distance and determining an evaluation model are overcome, the indeterminacy in realistic evaluation is reflected, and the flexibility, effectiveness and objectivity of transformer electromagnetic design scheme evaluation are improved.

The invention relates to an electromagnetic design method of an amorphous alloy transformer, which designs electromagnetic parameters of the amorphous alloy transformer by utilizing a circulating traversing method, and provides a calculation method of transformer iron core parameters, no-load loss and load loss considering the characteristics of an amorphous alloy material, effectively inhibits the local magnetic saturation and reduces the loss of the transformer; moreover the search space can be reduced, the search speed can be increased, and the reliability of the design scheme can be improved. Meanwhile, since the electromagnetic design of the amorphous alloy iron core power distribution transformer involves fewer variables, the calculation requirement of the circulating traversing method can be satisfied by utilizing the existing computer, and the cost for optimizing the computer system can be reduced.

The invention discloses an electromagnetic design method of a wideband camouflage screen wave absorber. The method includes the following steps that 1, a model is built for the wave absorber, whereinthe absorber includes a hollow hexagonal-prism structure and a gradient honeycomb structure; 2, a cross section of a hollow hexagonal-prism structure is selected, and equivalent electromagnetic calculation of equivalent structural materials in a plane region is conducted; 3, based on the equivalent structural material method of the plane region, equivalent electromagnetic calculation of gradient-honeycomb-structure materials of the wave absorber is conducted; 4, by establishing equivalent electromagnetic parameters of different gradient-honeycomb-structure materials, the reflectivity of structural materials of the wave absorber is calculated, and the structure of the wave absorber is optimized. The wideband wave absorber can be applied to camouflage screens of square weapon cabins, cavities, wave-absorbing buildings and the like, achieves excellent electromagnetic wave absorption or shielding effects, meanwhile has the characteristics of being waterproof on surface, preventing oxidation and being light and the like, and has an application prospect.

The invention relates to a unit layout and electromagnetic design method of a fuselage conformal array antenna. The method includes: (1) establishing a body coordinate system; (2) designing a unit arrangement form according to a fuselage structural characteristic, determining a unit spacing, and preliminarily determining a unit number and an array row number according to an electrical performance index; (3) determining position coordinates of the units on a fuselage; (4) selecting a radiation unit, establishing a local coordinate system shown in the description of each unit, and establishing a far-field pattern analysis model of a conformal array by employing a mathematical theory related to coordinate rotation; (5) superposing radiation patterns of the units to obtain a far-field analysis model of the whole array; (6) reducing the number of variables by employing a corrected Bernstein polynomial; and (7) regarding a pitching plane maximum side-lobe level and an azimuth plane maximum side-lobe level as a target function, performing optimization by employing a particle swarm optimization algorithm to obtain a control parameter of the corrected Bernstein polynomial, and sampling the polynomial to obtain an excitation amplitude value of an antenna unit.

The invention discloses an evaluation method for a transformer electromagnetic design scheme and relates to the technical field of transformers. The evaluation method comprises the following steps: (1) establishing a transformer electromagnetic design scheme evaluation index system, and selecting corresponding transformer electromagnetic design scheme evaluation indexes; (2) constructing an Analytic Hierarchy Process (AHP)-gray fuzzy comprehensive judgment model of the transformer electromagnetic design scheme; (3) determining each evaluation index weight of the transformer electromagnetic design scheme through an AHP; (4) calculating the membership of each evaluation index through a gray correlation coefficient, and performing single-factor evaluation; (5) performing fuzzy composite conversion on each evaluation index weight and a single-factor evaluation structure through a weighted average fuzzy operator to obtain an evaluation result. According to the evaluation method for the transformer electromagnetic design scheme, the transformer electromagnetic design scheme is evaluated correctly, scientifically and objectively by constructing the AHP-gray fuzzy comprehensive judgment model and adopting the AHP and a gray correlation calculation membership.

The invention relates to a multi-target robust optimization design method of an ultra-high-efficiency induction motor. Compared with the prior art, the technical defect that the robust optimization design of the ultra-high-efficiency induction motor is difficult to realize is overcome. The method comprises the following steps: obtaining a motor design variable based on the electromagnetic design of the ultra-high-efficiency induction motor of a rotor skewed slot and a single-layer and double-layer unequal-turn low-harmonic winding; determining a motor optimization variable based on a Taguchi test and reasonably dividing a multi-target optimization subspace; performing deterministic subspace multi-objective optimization based on a DE algorithm and Pareto evaluation; establishing a combined approximation model based on a Pareto solution set leading edge of a Monte Carlo sampling subspace; and evaluating multi-target performance and robust performance of the motor in consideration of optimization variable disturbance. According to the robust optimization design of the motor, the multi-objective optimization performance of the motor is improved, meanwhile, various uncertain factors in the production and manufacturing process of the motor are considered, and the robust performance of the motor is improved.

The invention provides an aerogenerator vibration and noise inhibition method and apparatus. The method comprises: calculating the given valve of generator field weakening control parameters in dependence on the given value of generator electromagnetic active power and the frequency of an generator; and controlling the generator in dependence on the given value of the generator field weakening control parameters. According to the invention, the magnetic loading of the generator can be reduced through field weakening control, and the vibration and noise of the generator are restrained. The mechanical structure and electromagnetic design of the generator do not need to be changed, thereby not influencing the power density and energy index of the generator, and not increasing the manufacture process complexity and manufacture cost of the generator.

The invention discloses a generator capable of long-term grid-connected operation. The generator electromagnetic design adopts H-level insulation and F-level temperature rise. Values of parameters such as current density, line load and flux density of the generator are lower than that of a general generator. The generator provided by the invention can adapt to the long-term operation condition of a generating set. The generator adopts an automatic digital voltage regulator and reactive distribution is reasonable. Three-phase voltage detection is adopted, the voltage regulation precision is high, the steady state voltage regulation rate of output voltage is smaller than or equals to + / -0.5%, the zero load line voltage waveform distortion rate is smaller than or equals to 3%, and grid-connected requirements of the generating set can be met. The generator adopts six-pole overall rotor punching sheets, the rotation speed is 1000r / min, the motor base adopts a large-span foot circular structure, the size is small, and the operation is stable. Vibration requirements of the generating set can be met. The advantages are that the generator is low in temperature rise; the voltage regulation precision is high; long-term grid-connected operation is achieved; the size is small, the operation is stable, the vibration is small, and the cost performance is high; and the generator is particularly suitable for a large and medium-sized long-term grid connected operation generating set.

The invention provides a sectional magnetic yoke structure of a synchronous alternating-current motor, which comprises a shaft and a magnetic yoke. The shaft comprises a magnetic yoke matching section and a shaft shoulder, the magnetic yoke matching section has a sectional structure, the diameter of each unit of the magnetic yoke matching section is reduced sequentially from left to right, the total length of the magnetic yoke matching section is larger than that of the magnetic yoke, the shaft shoulder is arranged on the left of the magnetic yoke matching section, and the diameter of the shaft shoulder is larger than that of the magnetic yoke matching section. The magnetic yoke has a sectional structure formed by welding a plurality of magnetic yoke plates and is sleeved on the magnetic yoke matching section of the shaft, and the left end of the magnetic yoke is butted to the shaft shoulder. The invention further provides a sectional magnetic yoke processing method of the synchronousalternating-current motor. The section magnetic yoke structure is simple and compact and evident in action effect. Processing and assembling are simpler and more convenient, manufacturing cycle is shortened and manufacturing cost is reduced by changing the magnetic yoke on the premise without changing the electromagnetic design.

The invention relates to the technical field of motors and discloses a permanent magnet brushless motor, a robot joint, a servo steering engine actuator and a robot. The motor is a fractional slot inner rotor motor and comprises a stator and a rotor, the stator comprises a stator core and a stator winding. The stator winding is a centralized winding, and the stator core is of an integrated structure. The stator core comprises a stator yoke part and a stator tooth part. The stator tooth part comprises a plurality of stator teeth arranged on the stator yoke part, and an insulating layer is arranged on the surface of each stator tooth; the stator winding comprises a preset number of winding coils formed by machine winding, and each stator tooth is sleeved with x winding coils, wherein x is greater than or equal to 1; the rotor comprises a permanent magnet and a permanent magnet carrier; and the permanent magnet is used for excitation to generate a rotating magnetic field. According to theembodiment of the invention, the slot fullness rate can be improved and the electromagnetic design can be optimized under the condition of ensuring the operation stability of the motor, thereby improving the motor constant density and output power density of the motor.

The invention relates to a magnetic field analysis method for designing an eccentric magnetic force gear and based on an analytical method. The eccentric magnetic force gear is composed of a high speed rotor, a low speed rotor and a stator. Aiming at an electromagnetic design of the eccentric magnetic force gear, a boundary perturbation method is employed to establish an analytical model; firstly, a permanent magnet of the stator is not magnetized, and an eccentric magnetic field under the individual effect of a permanent magnet of the low speed rotor is solved based on the analytical method; then the permanent magnet of the low speed rotor is not magnetized, and an eccentric magnetic field under the individual effect of the permanent magnet of the stator is solved; the two eccentric magnetic fields are linearly superposed, and an eccentric magnetic field under the common effect of the permanent magnet of the low speed rotor and the permanent magnet of the stator is obtained; and an electromagnetic torque of the eccentric magnetic force gear is solved in dependence on the distribution of the air gap magnetic flux density. The magnetic field analysis method for the eccentric magnetic force gear can be applied to electromagnetic designs of a plurality of eccentric magnetic force transmission devices such as eccentric magnetic force harmonic wave meshing gears, eccentric cascade magnetic force gear gearboxes, eccentric magnetic force gear drive discs and the like.

The invention relates to a permanent magnetic brushless constant voltage generator and a voltage stabilizing method thereof. The generator is driven by a speed change wind wheel, the sent constant voltage direct current is output to the electric network after the frequency conversion through an inverter, the leakage reactance per-unit value X<*> of an armature winding at the maximum work rotating speed of the generator equals to the ratio of the difference of the maximum work rotating speed and the minimum work rotating speed of the generator to the minimum work rotating speed, and the range of the leakage reactance per-unit value X<*> is from 1 to 1.8. The method increases the leakage inductance value of the armature winding of the generator through the optimized electromagnetic design on the generator per se, so the leakage inductance resistance of the armature winding of the generator in work is increased, the potential E of the generator is in isometric and synchronous change with the leakage resistance voltage reduction X.I of the armature winding when the rotating speed of the generator is changed in the work rotating speed range, and thus, the constant voltage output is realized. The generator can realize the voltage stabilization without increasing any detection and control links, executing mechanisms and the like, the structure is greatly simplified, the cost is greatly reduced, and the invention has the advantages of simplicity, economy, effectiveness and reliability.

The purpose of the invention is to provide a method for quickly calculating the steady-state linear model parameters of a permanent magnet synchronous motor and a three-phase synchronous reluctance motor under determined voltage, speed and output power based on two-dimensional electromagnetic field finite element analysis software, correct the correction parameters for correcting the steady-statemodel parameters in an electromagnetic design program based on magnetic circuit and obtain the main performance parameters of the motors under the determined voltage, speed and output power from the electromagnetic design program based on magnetic circuit. In order to achieve the purpose, one technical scheme of the invention provides a design method of a permanent magnet synchronous motor, and the other technical scheme of the invention provides a design method of a synchronous reluctance motor. According to the invention, a three-phase permanent magnet synchronous motor and a three-phase synchronous reluctance motor can be designed more accurately and more quickly.

The invention discloses a winding rotor motor for preventing accumulated dust adsorption and creepage. A stator and a rotor of the motor are made of a silicon steel sheet rolled by a high-performance energy-saving process; the electromagnetic design is performed in a standardized form according to the requirement; the motor driving and a collecting ring are treated by isolation; a part with a creepage preventing standard distance is needed to be insulated in a collecting ring area; and the surface of the part is completely treated by using nano particle insulated paint to form an insulated surface low-tension area which has self-clean performance and is not easy to accumulate and adsorb dust. With the fit of a motor end cover bearing chamber hole and a bearing outer ring, and referencing to three difference states of natural assembly, normal work and special work in which different matched materials are positioned as well as a clearance variable difference generated by an expansion coefficient, a normal work state can be selected as a matching reference and a design processing deviation can be determined by replacing the traditional selection mode by a computing mode. An O-shaped ring is additionally assembled to adjust when the expansion variable difference is larger. The invention always ensures that the bearing is operated in the state of oil froth, thereby achieving the aim of improving the non-fault operating time and the quality of the motor.

The invention provides a method for eliminating vibration of a PWM powered brushless direct current motor through frequency calculation. For the motor preliminarily designed in a electromagnetic scheme, spatial harmonic distribution of air gap flux density is firstly calculated, then the time harmonic wave change of the air gap flux density is calculated within a commutation period and is compared with the inherent vibration frequency of a motor iron core, and if the frequencies are similar, resonance is produced, the electromagnetic design scheme of the motor is needed to be optimized, and the frequencies are re-calculated till the vibrations produced by spatial harmonic flux density and harmonic wave flux density are not resonant with the iron core. The space and time changes of flux density causing motor vibration under the operating working condition of the motor are fully considered in the method, the accuracy of motor vibration calculation in a motor product development phase is improved, accordingly the success rate of motor design is improved, a development and trial-manufacturing period of the motor is shortened, and non-renewable resources including copper, iron, aluminum and the like are effectively saved.

The invention discloses a three-dimensional forming manufacturing system and method for a wave absorbing material. The method comprises the steps that 1, a resin substrate shaped wave absorbing material is prepared; 2, the structure inside the resin substrate shaped wave absorbing material is formed orderly; 3, the structure inside wave absorbing micro powder is manufactured orderly; 4, a hot melt plastic based wave absorbing material is manufactured in a three-dimensional forming mode; and 5, the hot melt plastic based wave absorbing material is controlled by a magnetic field. The invention further provides the three-dimensional forming manufacturing system for the wave absorbing material. The three-dimensional forming manufacturing system comprises a resin substrate shaped wave absorbing particle forming manufacturing module, an orderly distributed wave absorbing microsphere preparation module, a pulse type pressurization and temperature control printing module and a three-dimensional forming three-coordinate mechanism module. According to the three-dimensional forming manufacturing system and method for the wave absorbing material, the electromagnetic design and manufacturing of the wave absorbing material are combined, preparation and controllable manufacturing of the inner structure of the wave absorbing material of a complex structure are achieved, the designability of the wave absorbing material is improved, and the wave absorbing performance of the wave absorbing material is improved.

A Y junction single phase capacitor run motor electromagnetism designing method is characterized in that, the designing method comprises the following steps: 1) determining the designing input parameter of the designed motor; 2) manufacturing a three-phase motor model based on the designing input parameter; 3) inputting the three-phase motor model with the three-phase power supply to drive the rated load, measuring the phase end positive sequence resistance Rfm and the reactance Xfm of the motor; 4) using the two-phase winding of the three-phase motor model as the main phase and the assistant phase of the motor to be designed, wherein the effective turns of the middle phase winding to the main phase winding follow the above formula, and the capacitive reactance Xc of the capacitor accords to the following formula: Xc=2Xfm. The designing method omits the complex computation of Rfm and Xfm, and obtains the correct result coherent with the structure technique, to cause the motor to be designed to obtain better performance.

The invention relates to a motor, in particular to a port gantry crane low-noise lifting motor which solves the problem of great noise of the traditional port gantry crane low-noise lifting motor. The port gantry crane low-noise lifting motor comprises a base and a stator core, wherein the stator core is formed by laminating stator sheets, and a stator coil is arranged in the stator core; a frontend cover and a back end cover are respectively fixed at the two ends of the base, and a rotating shaft is supported on the front end cover and the back end cover through a bearing; a rotor core is arranged on the rotating shaft, the rotor core is formed by laminating rotor sheets, a conducting bar passes through rotor core slots, and both ends of the conducting bar and an end ring are welded into an integral mouse cage; the number of stator core slots is 54, and the number of rotor core slots is 66; and the stator coil is a preformed winding and is wound according to pitch 7 and winding short pitch ratio beta 7 / 9. Furthermore, the air-gap magnetic density in electromagnetic design is reduced to be lower than 0.9T. The motor meets the requirements of low noise and environmental protectionof port environment, and various performance indexes achieve the level of similar imported products.

The present invention relates to a magnetic field analysis method for design of a sine magnetization concentric magnetic gear based on an analytic method. The magnetic field analysis method sequentially comprises the following steps of: S1, establishing a sine magnetization permanent magnet array mathematical model and compiling a corresponding computing program; S2, giving a number of pole pairs, a magnetic pole dimension, a number of magnetic blocks on each pole and a magnetization direction of a sine magnetization inner and outer rotor permanent magnet array; S3, determining basic structural parameters of the sine magnetization magnetic gear; S4, calculating a static magnetic field of the gear by the analytic method; and S5, calculating electromagnetic torques and torque-angle characteristics of inner and outer rotors of the magnetic gear. The magnetic field analysis method for the concentric magnetic gear, which is disclosed by the present invention, can be applied to electromagnetic design of numerous concentric magnetic transmissions such as a concentric magnetic harmonic meshing gear, a concentric cascaded magnetic gearbox, a concentric magnetic gear transmission disk and the like.

The invention discloses a laser sight cooling pump. The laser sight cooling pump is characterized by comprising a machine case, a rear bearing, a rotor, a stator, a front bearing, a check ring, an impeller, a screw, a pump cover, an O-shaped ring, a rotor shielding sleeve, a stator shielding sleeve and a rear end cover. The laser sight cooling pump technology is a domestic pioneered overall shielding sleeve structure and a novel and unique electromagnetic design scheme. A motor and a water pump are combined into an integrated structure, the technical difficulties of sealing, corrosion preventing, high efficiency, low temperature starting performance and the like are successfully solved, incomparable work characteristics of pumps in other types and advanced technical indexes are achieved, and the laser sight cooling pump exceeds the level of foreign products of the same type.

The invention discloses a rotary electromagnet with symmetric magnetic paths. The rotary electromagnet comprises a front fragment cover and a rear end cover, wherein a rotor part is arranged on the front fragment cover and the rear end cover, stator parts are respectively arranged on the front fragment cover and the rear end cover at the two sides of the rotor part, the rotor part comprises a rotor shaft, the rotor shaft is arranged on the front fragment cover and the rear end cover via a first bearing and a second bearing and can rotate around a central axial line, a first permanent magnet, a second permanent magnet, a first rotor fragment, a second rotor fragment and a third rotor fragment are arranged at each of the two sides of the rotor shaft, and each stator part comprises a first yoke, a second yoke, a third yoke, a fourth yoke, a coil and a coil retaining rack. With the improved dual-magnetic steel electromagnetic design, the rotary electromagnet with the symmetric magnetic paths also can be fabricated by a mechanical processing mode, is simple in structure and is convenient to process.

The invention discloses a surface-mounted permanent magnet motor electromagnetic design method, and the method comprises the steps of simple magnetic circuit design and electromagnetic field finite element calculation of a permanent magnet motor. The simple magnetic circuit design mainly takes the technical requirements of the motor as input, and according to the basic formula of the motor electromagnetic design, the size of a stator core of the permanent magnet motor and the initial size of a rotor magnetic pole are determined; the electromagnetic field finite element calculation comprises static magnetic field calculation and transient magnetic field calculation, wherein the static magnetic field calculation is used for determining the radial size of a rotor magnetic pole, and the transient magnetic field calculation is used for determining the axial length of the motor. The method provided by the invention is not limited by the size of the permanent magnet motor, overcomes the defects of inaccurate coefficient and the like in an empirical formula in the traditional motor design and calculation process, considers the saturation characteristic of the motor in calculation, improves the accuracy of a calculation result, and is particularly suitable for design analysis of a surface-mounted permanent magnet motor.

The invention belongs to the technical field of electromagnetic induction, discloses a finite element analysis method of a switched reluctance motor and an external circuit thereof, determines parameters of the motor, performs electromagnetic design, and obtains a 2D / 3D model. The magnetic density profiles of the rotor with static field and 40A voltage at 0 degree, 7.5 degrees, 15 degrees and 22.5degrees were compared. The torque and rotational speed waveform is obtained by adding external circuit into the transient field. By analyzing the waveform and comparing the angular magnetic density distribution under different conditions, the external circuit design method of switched reluctance motor is as follows: through the reasonable design of some parameters of electronic components relatedto the external circuit, and then connect these electronic components to form the external circuit. The invention obtains relevant data in Ansoft Maxwell through finite element analysis and externalcircuit design of the switched reluctance motor, carries out data analysis and comparison, further optimizes and improves the design, and enables the motor to become more efficient and energy-saving.

The invention relates to a cylindrical rotor structure optimization method, which comprises the steps that a rotor of a linear switched reluctance motor is symmetrically and equally divided into Nr modules, then the Nr modules are divided into Ng groups, the number of the modules in each group is Nm, the heights of cylinder surfaces in each group are the same, and the cylinder surfaces between adjacent groups have an offset of alpha in the longitudinal direction; the force Fph (z, i) borne by each phase of rotor is calculated according to the longitudinal offset alpha of the rotor on the cylinder surface of the rotor; the propulsive force FSR (z, i) generated by the LSRAs is calculated according to the Fph (z, i); and the fluctuation coefficient fripple is obtained, and then the minimum value of the fluctuation coefficient fripple is obtained. The decoupling of a magnetic circuit and a circuit in geometric design is realized by adopting a transverse magnetic flux structure, and the design is flexible and convenient; the space displacement of a rotor module is optimized, so that the thrust fluctuation of the motor can be effectively reduced; the electromagnetic design, the appearance size and the control strategy of the motor do not need to be changed; therefore, the motor is simple, low in cost, feasible and effective.

The invention relates to a rotor of an alternating-current asynchronous motor, which comprises a rotor iron core sleeved on a shaft. A rotor clamping ring is respectively arranged at two ends of the rotor iron core; the rotor iron core consists of a plurality of rotor punching sheets by superposition; the edges of the punching sheets are provided with a plurality of sheet-punching grooves; one end of each sheet-punching groove points at the centers of the rotor punching sheets; and the other end of each sheet-punching groove is open. The alternating-current asynchronous motor is characterized in that the outside diameter of the rotor punching sheets is equal to that of the rotor iron core. A conducting rod is arranged in the sheet-punching grooves; an end ring is connected to the inner side at the end part of the conducting rod; the end part of the shaft is provided with a key groove; and an arc key for fixing the rotor iron core is arranged in the key groove. The invention has the advantages of simple structure, safety and obvious effect. Under the conditions of ensuring the safety and the reliability of the motor and keeping the electromagnetic design unchangeable, the processing time and the sheet-punching material are saved by changing the design of the punching sheets, thereby improving production efficiency and eliminating incipient faults in use.

The invention provides a motor electromagnetic design method based on probability analysis. The invention provides a motor electromagnetic design calculation method considering random variable fluctuation such as material performance, processing technology and external load during motor electromagnetic design calculation. The motor electromagnetic design calculation method based on probability analysis can correctly, scientifically and objectively design the electromagnetic scheme meeting the technical conditions and probability requirements, the standard deviation requirement corresponding tothe electromagnetic scheme can provide a basis for the process design, guidance suggestions are provided for the production process, and the potential design failure rate is greatly reduced.

The invention relates to the technical field of construction equipment, and discloses a concrete resiliometer for constructional engineering. The concrete resiliometer comprises a shell, a tail coveris fixedly mounted on the back surface of the shell, an elastic striking rod is movably mounted on the front surface of the shell, a central guide rod is fixedly connected to the end, located in the shell, of the elastic striking rod, and an elastic striking hammer movably sleeves the outer ring of the central guide rod. An elastic striking tension spring is fixedly connected between the front face of the elastic striking hammer and the interior of the shell, a guide block is fixedly connected to the end, close to the tail cover, of the central guide rod, the outer ring of the guide block is movably sleeved with a pressure spring, a center hole is formed in the middle of the guide block, and a battery is fixedly installed at the inner top of the center hole. An annular hole groove is formed in the middle ring position of the guide block, and a wire is spirally wound in the annular hole groove. By means of the electromagnetic design and the design of the two matched sliding sleeves, itcan be guaranteed that stability is good, and detection precision is high.