N-T characteristic analysis / T-I characteristic analysis
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165 - Efficiency Map for an IPM Motor |
Module:DP,LS,RT |
2012-01-25 |
IPM motors are not only an efficient motor that can use a wide drive range, but also a motor that can use the reluctance torque produced by the salient inductance in addition to the magnet torque produced by the permanent magnets and rotational magnetic field. Creating an efficiency map is advantageous for the motor and control designs because the efficiency varies by the rotation speed and torque. Creating an efficiency map generally requires a vast amount of calculations as well as the process to organize the results. However, an efficiency map can be generated easily using the JMAG-RT Viewer feature.
This example presents the use of the JMAG-RT Viewer to create an efficiency map for an IPM motor.
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163 - Current vs. Torque Analysis of an SPM Motor |
Module:DP |
2011-07-12 |
The relationship between the current and torque is a fundamental characteristic
of motors. The torque produced by the current increases linearly as the
current increases up to a certain point, but the torque produced by the
current decreases by the magnetic saturation when the current is increased
further. Understanding the current versus torque characteristics using
simulation is beneficial for examining the motor design and drive state.
This example presents the use of a magnetic field analysis to obtain the
current and torque characteristics that are fundamental to SPM motors.
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119 - Torque Characteristic Analysis of a Three Phase Wound Rotor Induction
Motor
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Module:DP |
2011-02-28 |
A choke coil is an electronic component use to prevent currents that exceed
the predetermined frequency. Measures to evaluate the heat source as well
as the core iron losses that occur within the choke coil and the copper
losses of the coil that decrease efficiency need to be used for this analysis.
The iron loss of the core can be obtained from the copper loss and iron
loss of the coil obtained with a mangetic field analysis in JMAG-Designer.
The example presents the use of a copper and iron loss analysis to obtain
the copper and iron losses of a choke coil.
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95 - Analysis of Characteristics of a Universal Motor
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Module:DP |
2011-01-17 |
Universal motors rotate by either AD or DC. Since universal motors have
a simple structure which is robust, compact, and capable of high speeds,
they are used in home appliances and industrial electric tools. Also, in
universal motors, the rotation speed is determined by the load when field
coil and armature coil are connected in series. This note presents the
use of magnetic field analysis to obtain the characteristics of the universal
motor, including torque versus current (T-I), torque versus speed (T-N),
and magnetic flux density distribution.
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68 - Analysis of a Three Phase Induction Motor for the Speed-Torque Curve
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Module:DP |
2011-07-12 |
In the induction motor, current is induced in the rotor cage by the rotating
magnetic field of stator coils, causing the rotor to turn. Induction motors
are widely used from industrial machines to home appliances since they
are small, light, affordable, and maintenance-free. Analyzing the current
induced in the rotor bars is important since the induced current essentially
determines the performance of the induction motor. This note presents the
use of magnetic field analysis to obtain the current density distribution
and the speed-torque curve of a three-phase induction motor.
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63 - Analysis of Torque Characteristics of a Cage Induction Motor
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Module:FQ |
2011-02-28 |
Induction motors have been widely used in general industries since they
have simple structure, and are affordable, robust and highly efficient.
When an induction motor rotates at synchronous speed, no torque is produced.
However, when it has a proper slip, the maximum torque can be obtained.
In a cage induction motor, when current flows in the cage, the loss is
caused. So, the duration of rotation needs to be controlled depending on
the amount of heat generation. This note presents the use of magnetic field
analysis to obtain the torque characteristics of a cage induction motor.
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56 - Torque Characteristics Analysis of a Self Starting Type Permanent
Magnet Motor
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Module:DP |
2011-02-31 |
A self starting induction motor that has a rotor and cage operates as an
induction motor when starting and as a synchronous motor when the motor
reaches synchronous speed with the poles of the permanent magnets. Self
starting type permanent magnet motors, often used in industrially or in
household appliances, do not require a starting device while providing
high-efficiency. Analyzing the current induced in the rotor bars is important
because the induced current essentially determines the performance when
the motor operates as an induction motor. For this reason, it is important
to evaluate the current that is induced in the self starting type permanent
magnet motor. This example presents the use of a magnetic field analysis
to obtain the current density distribution and the slip versus torque curve
of a self starting type permanent magnet motor.
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 | 8 - Analysis of an Axial Gap Motor UP!
| Module:TR | 2012-04-10 | Unlike typical cylindrical motors such as radial gap motors, axial gap motors have a structure in which the stator and the rotor, which is arranged on a disk, face each other and produce rotation. For that reason, because it is possible to arrange thinner parts than with a radial gap motor, they can respond to demands for miniaturization of equipment.
With axial gap motors, evaluations using the magnetic circuit method and empirical data are difficult because the magnetic flux that passes through the rotor and stator, which face each other, becomes a 3D magnetic circuit, meaning that a 3D electromagnetic field simulation using the finite element method (FEM) is necessary because it can carry out an accurate analysis.
This Application Note shows how to use JMAG's 3D magnetic field analysis to carry out a load analysis of an axial gap motor, and then obtain the Speed-Torque curve and the Torque-Current curve.
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 | 7 - Analysis of a Spindle Motor UP!
| Module:TR | 2012-04-10 | Spindle motors are often used as drive motors where limited space is an issue, as is the case with storage media like hard disks. They employ an outer rotor structure in order to obtain a large torque, but to do so they have to use a great deal of permanent magnets while remaining thin and compact. In order to reduce the number of parts used in their composition, the rotor core has functions that both bear the magnet's flux path and transfer the generated torque, which supports the magnet, to the shaft. For this reason the rotor core is composed of materials that are easy to produce, meaning that there is a possibility that its efficiency as a magnetic circuit will decrease. As motors get smaller, they require a design that accounts for flux leakage because it begins to affect the disc in the rotor.
For this reason, spindle motors need electromagnetic field simulations that use the finite element method (FEM), which can account for detailed 3D geometry and magnetic saturation in materials, in order to carry out an accurate evaluation.
This Application Note shows how the Speed-Torque curve, the Torque-Current curve and the magnetic flux density distribution of a spindle motor can be obtained.
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 | 3 - Analysis of a Permanent Magnet Brush Motor UP!
| Module:DP | 2012-04-10 | A brush motor generates torque through the electromagnetic attraction and repulsion between its rotor and stator. They do not have many parts and do not require drive circuits, so they are widely used as a power source for compact equipment. A brush motor is composed of a magnetic circuit part, which actually generates torque via electromagnetic phenomena, and the brush/commutator part, which corresponds to the drive circuit. In order to aim at improving the performance of a brush motor, it is necessary to raise the usage efficiency of the magnetic circuit in each part and expertly utilize the nonlinear material characteristics. Proper placement of the brush/commutator that correspond to the drive circuit is also vital.
In order to evaluate the usage efficiency of the magnetic circuit, torque variations, current waveforms, etc. at the design stage, it is best to first do a detailed calculation of the magnetic flux density in each part, and then perform an electromagnetic field simulation using the finite element method (FEM), which can evaluate torque with high accuracy.
This note presents how the characteristics of the brush-type PM motor can be obtained, including torque versus current (T-I), torque versus speed (T-N), and magnetic flux density distribution.
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 | 1 - Torque Characteristic Analysis of a Three Phase Induction Motor UP!
| Module:DP | 2012-04-10 | An induction motor is a motor in which the rotating magnetic field of the stator coils causes induced current to flow in an auxiliary conductor, exerting force on the rotor in the rotational direction and causing it to spin. Induction motors are widely used in everything from industrial machines to home appliances because they have a simple construction and are small, light, affordable, and maintenance-free.
In an induction motor, the current induced by the auxiliary conductor exerts a large influence on its characteristics. It also causes strong magnetic saturation in the vicinity of the gap, in particular. With Finite Element Analysis (FEA), it is possible to investigate the characteristics that accurately evaluate the features listed above, so preliminary design evaluations are effective.
This Application Note introduces a case example of how to obtain the current density distribution of an auxiliary conductor and its rotation speed versus torque characteristics.
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