DS - Static/Dynamic Structural (2D/3D)  | 142 - Press Fit Analysis of a Divided Core
| Module:DP,DS,LS | 2013-02-28 | Smaller size and higher output are being demanded of the motors used for applications such as air conditioning compressors. One production technique for achieving this is a higher lamination factor in divided cores. The stress caused by press-fitting a divided stator core into a frame is known to increase iron loss in a motor if magnetic steel sheet is used for the core.
Iron loss is affected by magnetic flux density and stress. Specifically, it increases in areas of high magnetic flux density with high frequency, and in areas of high stress. Further, the stress caused by press fitting has its own distribution, and is particularly large in the core and back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the magnetic flux density distribution, time variations, and stress distribution.
This Application Note presents how to use the Press Fit condition to model an analysis of the stress from fitting a core to a frame, and then obtain the iron loss density of an IPM motor under no load, with and without accounting for the stress.
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  | 138 - Vibration Analysis of an SR Motor
| Module:DP,DS | 2011-07-12 | SR motors are utilized because they have a simple construction that doesn't use permanent magnets making them robust yet inexpensive when compared to other motors.
However, the electromagnetic force produced by the saliency of the stator and rotor cause vibrations and noise.
This example presents the use of a coupled magnetic field and structural analysis to obtain the electromagnetic force of the SR motor and the resonance of the eigenfrequency in the stator core.
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 | 128 - Structural Analysis of a Cantilever
| Module:DS | 2011-01-17 | The importance of strength design for devices is growing with the miniaturization and flattening of electrical equipment and measures to reduce vibrations are in even greater demand.
To understand the characteristics of electrical equipment, the vibration characteristics and strength of each part that make up the device need to be accurately evaluated. Therefore, the phenomenon of each individual part needs to be correctly analyzed first.
This example presents the use of a structural analysis to obtain eigenmodes and displacement that has a concentrated load for 3 types of mesh models of a simple cantilever. These results are then compared to the theoretical values.
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 | 124 - Cogging Torque Analysis of an SPM Motor Accounting for an Varied Stator Diameter
| Module:DP,DS | 2011-02-28 | When a motor is constructed, the diameter of the stator becomes uneven because of fabrication errors and shrink fitting. It is advantageous to investigate the uneven diameter of the stator because it largely effects the cogging torque.
This example presents the use of a structural and magnetic field analysis to obtain the cogging torque with stator teeth that have an uniform and varying diameter based on the displacement obtained with a stress analysis.
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 | 114 - Vibration Analysis of an Outer Rotor Motor
| Module:DP,DS | 2012-07-31 | An outer rotor motor has a magnetic rotor that rotates around a stator. The rotor radius of an outer rotor motor is large, so it can produce a larger amount of drive torque than an inner rotor motor with the same diameter, giving it a superior constant velocity. On the other hand, countermeasures for vibration and noise that occur during rotation are vital as well.
The electromotive force is a cause of the vibration that occurs when a motor rotates. Additionally, when this electromotive force resonates with the motor's eigenmodes, it causes even larger vibrations and noise. Countermeasures such as changing the motor's eigenfrequency through processes like setting a hole in the rotor core have been taken with the objective of preventing resonance. In order to carry out these kinds of studies, it is necessary to get a precise, definite grasp of the electromotive force's spatial distribution, frequency analysis, and natural frequency.
This note presents the use of a magnetic field analysis and structural analysis to obtain the sound pressure caused by electromagnetic vibrations in an outer rotor motor with holes fabricated in the rotor core.
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 | 108 - Centrifugal Force Rupture Analysis of a Ring Magnet
| Module:DS | 2013-02-28 | As the applications for permanent magnet synchronous motors expand in the manufacturing sector, the development of high-speed-capable motors is continuing apace. One problem during high-speed operation is centrifugal force produced in the rotor, because, in an SPM using ring magnets, a magnet can rupture when the stress acting on it surpasses its mechanical strength. Analyzing the maximum rotation speed of a motor in advance to evaluate methods to prevent the magnet from rupturing, such as designing reinforcing rings, is highly advantageous during the design stage.
When an SPM motor rotates, centrifugal force is generated, producing stress on the magnets. The stress distribution inside the magnets is not uniform. In addition to evaluating their mechanical strength, it is necessary to thoroughly investigate areas of stress concentration using the finite element method (FEM).
This Application Note presents how to obtain the stress distribution of a ring magnet in an SPM motor rotating at high speeds.
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 | 97 - Sound Pressure Analysis of a Transformer
| Module:DS,FQ | 2011-07-12 | In recent years, the demand to reduce vibration and noise is growing while the requirements for higher efficiency and smaller and lighter transformers grow with environmental conservation trends. The primary cause of noise for transformers is the electromagnetic vibrations and the resonance phenomena at the eigenfrequency of the structure. A sound pressure analysis can be performed with a coupled magnetic field and structural analysis that uses the electromagnetic force as excitation force.
This example presents the use of a coupled magnetic field and structural analysis to obtain the sound pressure distribution accounting for the electromagnetic force of the core when the transformer is operating on a power supply frequency of 6 kHz.
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 | 91 - Iron Loss Analysis of an IPM Motor Including the Effects of the Press Fitting Stress
| Module:DP,DS,LS | 2013-02-28 | One of the demands for IPM motors is higher efficiency over a wide range of rotation speeds in combination with motor drives, as reluctance torque can be used in addition to magnet torque. Iron loss makes up a particularly large proportion of total loss in the high rotation region, and how to make this smaller is a major design issue. Generally, IPM motor cores have laminated structures, and methods such as press fitting or shrink fitting are used to maintain them.
For motors using magnetic steel sheet for their cores, the stress generated by press fitting can increase iron loss, so it is important to take this stress into account when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as press fitting. The stress caused by press fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents modeling the press fitting of a core and frame with the Press Fit condition and then obtaining the iron loss density of an IPM motor with and without accounting for the stress generated at that time.
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 | 87 - Iron Loss Analysis of an IPM Motor Including the Effect of Shrink Fitting
| Module:DP,DS,LS | 2013-02-28 | Magnetic steel sheet is used for the cores of drive motors for HEVs and EVs. This is to make them more compact, lighter, and more efficient. The main point for improving efficiency in an IPM motor's high rotation speed region is how to reduce iron loss. However, shrink fitting is used in order to strengthen the joint between frames and stator cores with laminated structure. The compressive stress generated during shrink fitting is known to increase iron loss. Therefore, it is important to account for the effects of this stress when evaluating iron loss.
Iron loss is generated when there are magnetic-field variations in steel sheet. Also, the amount of iron loss depends on the steel sheet's iron loss properties. These iron loss properties of steel sheet become worse when it is subjected to stresses such as shrink fitting. The stress caused by shrink fitting has its own distribution, and is particularly large in the back yoke. So, in order to evaluate the iron loss with good accuracy, it is necessary to correctly obtain the stress distribution for the magnetic flux, time variation, and steel sheet.
This Application Note presents how to obtain the iron loss density of an IPM motor with and without accounting for this stress.
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 | 42 - Displacement Analysis of a Piezoelectric Actuator
| Module:DS | 2008-11-27 | Piezoelectric elements are used as actuators and sensors, as well as oscillator circuits and filter circuits in the analog electronic circuits. When the electric potential is applied, the piezoelectric element is deformed. This is called the converse piezoelectric effect. In JMAG, the analysis of the piezoelectric actuator using the converse piezoelectric effect can be performed by specifying the permittivity matrix and the electric potential for the material.
This note presents the use of structural analysis to evaluate the displacement of a bimorph piezoelectric actuator, caused by the inverse piezoelectric effect.
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 | 31 - Iron Loss Analysis of an SPM Motor Including the Effect of Press-fitting Stress
| Module:DP,DS,LS | 2013-01-28 | The laminated structure of a core in a SPM motor can be sustained using press-fitting or shrink fitting. The press-fitting stress needs to be accounted for in the iron loss evaluation because the stress caused by press-fitting is known to increase the iron losses when a magnetic steel sheet is used for the core of the motor.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. The iron loss characteristics of a steel sheet deteriorates by stress from press fit coupling. The stress generated by the press fit coupling is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents the use of the press fit condition to model a core and frame and obtains iron loss density for when the generated stress is used and not used.
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 | 21 - Iron Loss Analysis of an SPM Motor Including the Effect of Shrink Fitting
| Module:DP,DS,LS | 2013-01-28 | A magnetic steel sheet is used for the iron core in a motor. A frame is shrunk into a stator core in order to sustain the laminated structure and to improve the strong joint between the frames. It is know that a compressive stress is generated during the shrinking process which increases the iron loss process. Therefore, it is important to account the affects of stress during iron loss evaluation. Therefore, it is important to account the affects of stress during iron loss evaluation.
An iron loss is generated by the magnetization field in displacement with a steel sheet. The size of the iron loss is dependent on the iron loss properties of a steel sheet. Iron loss characteristics of a steel sheet deteriorates when there is stress in shrinkage. The stress generated by the shrinkage is distributed in areas in which the section in the back yoke becomes large. In order to evaluate the iron loss with good accuracy, it is necessary to obtain the stress distribution for the magnetic flux, time variation, and steel sheet with accuracy.
This note presents an analysis to obtain the iron loss density of an SPM motor both including and not including the stress caused by shrink fitting.
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 | 20 - Sound Pressure Analysis of an SPM Motor
| Module:DP,DS | 2012-07-31 | As electric motors are becoming more common, motors which create less noise are in high demand. Sound can be divided into categories of electromagnetic noise, mechanical noise, and draft noise, where electromagnetic noise is the most common for medium and small sized motors. Sound can be divided into categories of electromagnetic noise, mechanical noise, and draft noise, where electromagnetic noise is the most common for medium and small sized motors.
The electromagnetic force in a motor vibrates as an electromagnetic excitation force which creates noise. The vibration and noise are generated when the electromagnetic excitation force resonates with the motor's eigenmodes. In order to evaluate this phenomenon more accurately, it is necessary to understand the distribution of electromagnetic force that moves the stator core which is the basis for the radiated sound. The distribution of electromagnetic force or the eigen modes in a model that depends on the geometry of a stator core is required for running an analysis such as for the finite element analysis.
This Application Note shows an example of an evaluation of a reactor's sound pressure, when acquiring electromagnetic force generated by a stator core for a SPM motor and linking the eigen modes of a motor.
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 | 19 - Analysis of the Centrifugal Force in an IPM motor
| Module:DS | 2013-01-28 | While motors have started being combined with motor drives and used in a wide range of velocities, further changes toward high output and high efficiency are being demanded of them. While high speed revolution has been given as a means of attaining a higher output, the magnets have a weaker intensity than the steel sheets, so evaluations from the standpoint of mechanical strength are necessary because the centrifugal force grows large during rotation.
IPM motors have a structure that embeds the magnet in the rotor. Centrifugal force kicks in during motor drive, so the magnet becomes pressed against the rotor core because it gets peeled off or displaced, making it so that a strong local stress begins to operate. It is necessary to correctly handle the phenomena of a magnet peeling off or becoming displaced in order to accurately obtain the local stress distribution. It is important to account for the adhesion and contact conditions between the magnet and rotor core in an analysis in order to do this.
This Application Note presents examples of cases that obtain changes and stress distribution from the centrifugal force in the rotor when the magnet is both fully and partially adhered to the rotor core.
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 | 9 - Sound Pressure Analysis of a Loudspeaker UP!
| Module:DS,TR | 2013-04-26 | A loudspeaker produces sound when the voice coil makes the vibrator vibrate. The general requirement of the loudspeaker is to produce uniform sound over a wide range of the frequencies.
Lorentz force is generated in the coil when the magnetic field of a permanent magnet acts on the current flowing through the voice coil, and produces sound by making the vibrator vibrate. In order to evaluate the sound with good accuracy, it is necessary to handle the resonance phenomenon between the Lorentz force and the speaker's eigenmode properly. The eigenmode and Lorentz force distribution change depending on the place where the core and coil are wound, so high accuracy calculations need to be carried out using the finite element method (FEM).
This Application Note presents how the frequency characteristics of sound pressure can be obtained using the constant Lorenz force on the voice coil, regardless of the frequency.
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 | 4 - Sound Pressure Analysis of a Reactor UP!
| Module:DS,TR | 2013-04-26 | Reactors are used in a variety of electric power systems. For instance, they fill the role of making the current pulsation between an inverter and a motor more smooth. On the other hand, the sound that originates from a resonance phenomenon between an electromagnetic force and an eigenfrequency can become a problem.
The reactor in this analysis has a gap in the magnetic circuit to prevent magnetic saturation. Due to the magnetic fields that occur with high frequency currents, electromagnetic force generates near the gap, and this electromagnetic excitation force in turn causes noise. Vibration and sound grow larger when the electromagnetic excitation force and the transformer's eigenmode resonate. In order to evaluate this phenomenon with good accuracy, it is necessary to find the electromagnetic force distribution and eigenmode in the high frequencies that become particular problems by using the finite element method (FEM).
This Application Note shows an example of an evaluation of a reactor's sound pressure when a part of a spacer has been removed.
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