No-load characteristic analysis  | 159 - Influence Analysis of Dimension Tolerance using Morphing
| Module:DP | 2013-01-28 | The angle of the magnets in SPM motors use a fillet or chamfer. However, the fillet and chamfer of each product that is manufactured varies because to completely fabricate the same fillet or chamfer is difficult in the manufacturing process. Therefore, the dimensional tolerance is set so the motor performance is not affected by these variations.
This example presents the use of a magnetic field analysis to compare whether the cogging torque of the SPM motor is influenced by changing geometry in the tolerance range assuming the dimensional tolerance of the chamfer is ±0.4 mm.
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  | 129 - Characteristic Analysis of a PM Stepping Motor Accounting for Magnetization
| Module:ST,TR | 2011-01-17 | Stepper motors are commonly used for positioning in printers and digital cameras.
The magnetization of the magnets used for the PM stepping motor largely affect the motor's characteristics.
Therefore, it is advantageous to accurately measure the characteristics of the PM stepping motor by clearly defining the magnetization with an analysis.
This example presents the use of magnet field analyses to obtain the induced voltage of a PM stepping motor that combines magnetization distribution, surface flux density, and magnetization of magnets magnetized with a magnetization device.
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 | 80 - Cogging Torque Analysis of an SPM Motor with Skewed Magnetization
| Module:TR | 2013-02-28 | Reductions in vibration and noise are being sought after because they are a cause of torque variations in motors, and demands for reduction are particularly strong with motors that are used in machine tools and power steering. Cogging torque, which is a torque variation that is produced when there is no current, is generated because the electromagnetic force produced in the gap changes according to the rotor's rotation. This makes it necessary to apply skew to the stator and rotor and come up with innovative geometry for the magnet and stator in order to reduce torque variations by limiting variations in the electromagnetic force. Applying skew reduces the cogging torque, but it also brings disadvantages such as producing force in the thrust direction and generating eddy currents from the magnetic flux that links in the lamination direction.
Consequently, in order to accurately evaluate a motor that has skew applied, one needs a magnetic field analysis simulation that uses the finite element method (FEM), which can account for a detailed 3D geometry, instead of studies that use the magnetic circuit method or a 2D magnetic field analysis.
This Application Note presents the use of a magnetic field analysis to obtain the flux density distribution, cogging torque, and induced voltage of an SPM motor that has skewed magnetization applied to its magnet.
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 | 55 - Integrated Magnetization Analysis of an IPM Motor
| Module:DP,ST | 2013-01-28 | Interior permanent magnet (IPM) motors often use strong rare earth magnets. They have poor workability, however, because the magnets are inserted into the rotor's small gaps during the assembly process. After the magnets have been inserted the rotor generates a strong magnetic field, which means that the workability when embedding it into the stator gets worse, as well. This is why in some cases they assemble the magnets while still in an unmagnetized state and magnetize them after they have been assembled. This construction method is called integrated magnetization. Using this means of construction can improve the assembly process a great deal, but there is also the possibility that the magnets will not be completely magnetized.
Consequently, first one needs to confirm whether or not integrated magnetization is even possible, and then from there to estimate the electrical power that the equipment needs for magnetization.
Using a magnetic field analysis simulation with the finite element method (FEM) provides the ability to change the making current amount and yoke geometry as magnetization conditions, as well as to account for magnetic saturation and evaluate whether or not the magnets are completely magnetized.
This Application Note explains how to determine the changes that occur in a magnetizing field if the making current is changed during magnetization, as well as how to obtain the induced voltage and cogging torque in the motor using the aforementioned magnets.
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 | 46 - Sensitivity Analysis of the Magnetization Pattern of an SPM Motor UP!
| Module:DP,ST | 2013-04-26 | The magnet in a surface permanent magnet (SPM) motor is arranged on the rotor's surface, facing the stator. The motor produces torque from the interaction between the magnetic field produced by the magnet and the magnetic field produced from the excitation coil. Cogging torque, which is generated during no-load rotation, depends largely on the magnet's magnetizing state. Adjusting the magnet's magnetization pattern makes it possible to reduce the cogging torque, which lowers efficiency and causes vibration and noise.
In order to control the magnetization pattern in the magnet of an actual machine precisely, a great number of magnetization devices is required. This makes a real machine hard to control, but with a magnetic field analysis simulation that uses the finite element method (FEM), it is possible to estimate how the cogging torque in the physical phenomenon will change by simply setting the magnetization pattern. Once the optimum magnetization pattern has been found, studying the magnetization method can lead to a reduction in development cost.
This Application Note presents the use of a magnetic field analysis to obtain the surface flux density for radial pattern, parallel anisotropic pattern, and polar anisotropy pattern magnets. It also displays the changes in induced voltage and cogging torque caused by differences in the magnetization patterns.
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