Basic characteristic analysis
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161 - Line Start Analysis of a Three-phase Induction Machine |
Module:DP |
2011-07-12 |
Line starting that is connected directly to the power supply of an electric machine is the simplest starting method of induction machines. A large current flows at the initial start up for line starting because the impedance at a stationary state is smaller than the impedance at a steady drive state. Understanding the basic characteristics for starting the machine using simulation is advantageous because of the effects to the power supply, the electromagnetic force acting on the coil, and then thermal capacity when starting the induction motor are vital.
This example presents the use of a magnetic field analysis to obtain the starting characteristics, such as the rotation speed variations, by simulating the line starting for an induction machine.
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156 -Segregation Analysis of Torque Components for an IPM Motor
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Module:DP |
2011-02-28 |
IPM motors are increasingly used in applications such as air conditioners
and automobiles because they can utilize both reluctance torque and magnet
torque. Generally, equation (1) is used to segregate the magnet torque
and reluctance torque of an IPM motor.
The torque can be segregated by obtaining the inductance from equation
(1). However, the effect of the magnets/current on the magnetic circuit
cannot be visualized. This note presents the use of a magnetic field analysis
to segregate the torque and obtain the magnetic circuit produced by each
type of excitation force.
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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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82 - Analysis of a Synchronous Reluctance Motor
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Module:DP |
2011-01-17 |
Synchronous reluctance motors with no magnet in the rotor are a robust,
inexpensive, and variable-speed drive motor. The cylindrical iron core
rotor has multiple air gaps, at which the magnetic flux flows in the vertical-axis
direction and hardly flows in the horizontal-axis direction. So, the synchronous
reluctance motor is rotated only by reluctance torque due to the saliency
of the iron core. This note presents the use of magnetic field analysis
to evaluate the average torque with sine wave current drive at each current
phase.
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81 - AL-value Analysis of a Choke Coil
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Module:ST,TS |
2011-02-28 |
The AL-value is one of the vital parameters when designing choke coils.
Analyzing the air gap versus the AL-value using simulations is advantageous
because the AL-value is often set by the design specifications and it varies
with the width of the air gap.
This example presents the use of a magnetic field analysis to obtain characteristics
of the air gap versus the AL-value for a choke coil.
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80 - Magnetization Analysis of an SPM Motor with a Skewed Magnet |
Module:TR |
2011-01-31 |
Motors are not only required to be more compact and have higher efficiency, but also to have less noise and vibration. One of the reasons of noise and vibration is cogging torque, which is caused by the interaction between the iron core and the permanent magnet. Cogging torque can be reduced by applying skew.
This note presents the use of magnetic field analysis to evaluate the magnetic flux density distribution and cogging torque of an SPM motor with a skewed magnet.
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74 - Speed Vs. Torque Analysis of a Single-phase Induction Motor
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Module:DP |
2011-07-12 |
Induction motors are widely used because they have a simple construction
that offers a motor that are compact, lightweight, affordable, and robust.The
induced current flowing in the cage largely effect the performance of the
motor because the motor rotates with the interaction between the magnetic
field of the stator windings and the induced current that flows through
the cage. Evaluating the relationship between the induced current and performance
of the motor using a magnetic field analysis is advantageous.This example
presents the use of a magnetic field analysis to obtain the current density
distribution and the speed versus torque characteristics of a single-phase
induction motor.
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71 - Analysis of a Slot Motor: 2 Brushes, 6 Poles, and 19 Slots
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Module:DP |
2011-01-17 |
A brush motor rotates when the brush and commutator alternate the direction
of the current passing through the armature coils.The torque needs to be
evaluated based on the rotation speed of a motor because the torque varies
with the rotation speed if the supply voltage is constant.Evaluating the
relationship between the torque and current during the design stage is
also advantageous because the torque is proportional to the current.This
example presents the use of a magnetic field analysis to obtain the speed
versus torque curve and torque versus current curve for a slot motor that
has 2 brushes, 6 poles, and 19 slots.
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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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65 - Analysis of Static Thrust of a Voice Coil Motor
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Module:TR |
2011-01-17 |
Coreless linear actuators are used for the head drive of electronic packaging
machines and precision stages, both of which require high accuracy positioning.
Static thrust has a great effect on accurate positioning, since it varies
with the translation position of an actuator. Also, static thrust varies
with the amount of current, so it is important to obtain the static thrust
at each supply current from the analysis. This note presents the use of
magnetic field analysis to obtain static thrust characteristics of a voice
coil motor at different translation positions and different supply currents.
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64 - Thrust Force Analysis of a Coreless Linear Motor
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Module:TR |
2011-01-17 |
Coreless linear motors are used for linear motor stages and electronic
packaging machines. Generally, the thrust force of a coreless linear motor
is smaller than that of an iron core linear motor. Since a coreless linear
motor has no cogging, its thrust force variation is much less than an iron
core linear motor. This note presents the use of magnetic field analysis
to obtain the thrust force of a coreless linear motor.
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43 - Torque Analysis of a Coreless Motor
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Module:TR |
2011-01-17 |
A coreless motor provides advantages, such as a reduction in torque ripple
and inertia, because the rotor does not have an iron core. A coreless motor
can also reach higher speeds because there is no iron loss.While a coreless
motor has both superior response and control, the manufacturing costs increase
to improve miniaturization and performance as they require materials such
as costly magnets.Therefore, examination through the magnetic field analysis
becomes more advantageous as various innovations to lower the costs of
manufacturing small, high-performance motors are necessary. This example
presents the use of the magnetic field analysis to obtain the torque waveform
amplitude of a coreless motor.
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32 - Analysis of a Transformer
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Module:FQ |
2011-01-17 |
A transformer is an electrical device that converts the voltage level of
alternating-current power using electromagnetic induction.
Although the secondary voltage is required to be constant regardless of
the load, it varies with amount of the load and the power factor. To ensure
the access to constant voltage, the size of the voltage variation is one
of the important output characteristics of the transformer.
Maintaining the balanced state is also the critical issue, since the imbalanced
voltage and current of each phase may cause the trouble to the device as
well as the temperature rise.
This note presents the use of magnetic field analysis to evaluate the changes
in the secondary voltage caused by the load variation of a low frequency
transformer.
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28 - Magnetic Field Analysis of a Speed Sensor
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Module:TR |
2011-01-17 |
Magnetic sensors have been used as automotive sensors.It is important that
the accuracy, sensitivity and the responsiveness of the sensors must be
ensured while the car is operating.The sensor performance improves if magnetic
core is placed close to the wheel. However, it is also important to have
adequate distance between them to avoid some dirt or foreign objects from
being stuck.This note presents the use of magnetic field analysis to evaluate
the voltage signal that varies with distance.
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 | 16 - Analysis of a Hybrid Stepper Motor UP!
| Module:TR | 2012-04-10 | Hybrid stepper motors are used as actuators for equipment where position detection accuracy is required, such as the joints of robots or rotary tables for machine tools. The rotor has a construction that sandwiches a magnet that is magnetized in the axial direction between two rotor cores that have serrated teeth to create salient poles, and the tips of the stator core's teeth are shaped like gears as well. The rotation resolution is determined by the number of gears in the rotor and the number of phases in the drive coil, so the number of gears is set to rather large numbers like 50 and 100 to raise the angle resolution. The most important characteristics for a stepper motor are the controllability, the detent torque, which is a non-excitation holding torque, and the stiffness torque, which is an excitation holding torque, and not the motor's output.
The two-plated rotor core of a stepper motor has an N pole on one side and an S pole on the other, so a multipole magnet is achieved by deviating the saliency of the gear condition by 1/2 pitch. Consequently, the magnetic circuit is 3D. There are also times when the division pitch geometry of the teeth is complicated, so it is necessary to carry out a 3D electromagnetic field analysis using the finite element method (FEM) to proceed with an accurate preliminary study.
This Application Note describes how the detent torque and stiffness torque can be calculated for a hybrid stepper 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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