3-D magnetostatic field calculation for a magnetic circuit with no (a narrow) air gap

1989 ◽  
Vol 25 (5) ◽  
pp. 3266-3268 ◽  
Author(s):  
T. Morisue
Keyword(s):  
Magnetic Circuit ◽  
Air Gap ◽  
Field Calculation ◽  
Magnetostatic Field

MAGNETOSTATIC FIELD ANALYSIS OF DC COMMUTATOR MOTORS WITH GEAR-TEETH ON THE ROTOR

2017 ◽  
Vol 41 (4) ◽  
pp. 555-569
Author(s):  
Guan-Chen Chen ◽  
Hong-Sen Yan
Keyword(s):  
Flux Density ◽  
Magnetic Circuit ◽  
Torque Ripple ◽  
Open Circuit ◽  
Air Gap ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Gear Teeth ◽  
Torque Ripples

This paper presents the open-circuit magnetostatic field analysis of a DC commutator motor by applying 1-D and 2-D equivalent magnetic circuit methods. For the 1-D and 2-D equivalent magnetic circuit method, the average air-gap flux density of a DC commutator motor and magnetic flux in every node are derived respectively, and the validity is verified by the finite-element analysis. The Carter’s coefficient is applied to model the permeance of the slot and gear-teeth space. The differences of the air-gap flux density are 3.21% and 3.06% for 1-D and 2-D methods, respectively. The flux linkages, back-EMF constants, cogging torques, electromagnetic torques, and torque ripples of the two gear profiles with feasible number of teeth integrated on the rotor are analyzed to verify the effects of gear profiles. The result shows that the gear-teeth integrated on the motor act as dummy slots, which reduce the cogging torque and torque ripple by 92.02% and 50.14 %, respectively.

Effects of contact gap on nondestructive evaluation using magnetic measurement for ferromagnetic steel

2020 ◽  
Vol 64 (1-4) ◽  
pp. 969-975
Author(s):  
Hiroaki Kikuchi ◽  
Yuki Sato
Keyword(s):  
Magnetic Flux ◽  
Nondestructive Evaluation ◽  
Effective Permeability ◽  
Magnetic Circuit ◽  
Magnetic Measurement ◽  
Air Gap ◽  
Motive Force ◽  
Hysteresis Curve ◽  
Evaluation Technique ◽  
Ferromagnetic Steel

We investigated effects of contact gap on magnetic nondestructive evaluation technique using a magnetic single-yoke probe. Firstly, we evaluated hysteresis curves and impedance related to permeability of the material measured by a single-yoke probe, when an air gap length between the probe and specimens changes. The hysteresis curve gradually inclines to the axis of the magneto-motive force and magneto-motive force at which the magnetic flux is 0 decreases with increasing the gap length. The effective permeability also decreases with increasing the gap thickness. The incremental of gap thickness increases the reluctance inside the magnetic circuit composed of the yoke, specimen and gap, which results in the reduction of flux applying to specimen.

Failure Mechanism Analysis of Electromagnetic Relay under Mechanical Impact

2013 ◽  
Vol 473 ◽  
pp. 39-45 ◽  
Author(s):  
Guo Wei Zhao ◽  
Yong Chen ◽  
De Yong Li ◽  
Bin Tang
Keyword(s):  
Failure Mechanism ◽  
Magnetic Circuit ◽  
Impact Damage ◽  
Engineering Application ◽  
Air Gap ◽  
Mechanism Analysis ◽  
Mechanical Impact ◽  
Electromagnetic Relay ◽  
Electromagnetic Relays ◽  
The Impact

The aim was to analyze failure mechanism of electromagnetic relay caused by mechanical impact. The principle of electromagnetic relays was studied and the effect of mechanical impact on electromagnetic relays was analyzed in this paper. Based on the established magnetic circuit model, the relationship of the magnetic field strength, the electromagnetic attraction and the impact damage degree was studied. Then, the damage intensity of mechanical impact on magnetic circuit was decided. Afterwards, the structure of electromagnetic relays was improved, and the mechanical impact simulation was studied by ANSYS. The results show that the uncontrollability of electromagnetic relay is mainly caused by air gap, which is aroused by mechanical impact; in addition, the size of air gap is inversely proportional to electromagnetic attraction force. Moreover, the improved structure of relays can increase impact resistance and broaden the scope of engineering application of electromagnetic relay.

Influence of Load and Air Gap Dimension on Magnetic Field and Magnetic Circuit Design of a Hightorque Stepmotor

1995 ◽  
pp. 343-346
Author(s):  
Wagner Juraj ◽  
Maga Dušan ◽  
Guba Roman ◽  
Führichová Renáta ◽  
Opaterný Jozef
Keyword(s):  
Magnetic Field ◽  
Circuit Design ◽  
Magnetic Circuit ◽  
Air Gap

A Spinner Magnetometer for Susceptibility Anisotropy in Rocks

1975 ◽  
Vol 12 (8) ◽  
pp. 1448-1464 ◽  
Author(s):  
P. C. Boetzkes ◽  
D. I. Gough
Keyword(s):  
Permanent Magnets ◽  
Magnetic Circuit ◽  
Air Gap ◽  
Johnson Noise ◽  
High Precision Measurement ◽  
Specimen Holder ◽  
A Value ◽  
Bulk Susceptibility ◽  
Weakly Magnetic ◽  
Nyquist Noise

The study of rock fabric through the anisotropy of magnetic susceptibility requires instruments capable of high-precision measurement of weakly magnetic sedimentary rocks. The magnetometer here described is such an instrument. The rock specimen spins on a shaft in an air-gap in a closed magnetic circuit of permalloy with barium ferrite permanent magnets. The air-gap is designed to apply to the rotating specimen a very uniform flux density with a value of 0.115 tesla when the magnets are saturated. Magnetizing coils integral to the transducer are used to magnetize or demagnetize the permanent magnets. Coils in the specimen gap detect specimen magnetization parallel and perpendicular to the applied field. The magnetic circuit forms a balanced bridge and allows alternative modes of transduction. The design is such that Nyquist noise is the largest noise contributed by the magnetic circuit and is smaller than the Johnson noise from the detector coils. Measured noise from the completed transducer is only 4.7 dB above the Johnson noise. The limiting sensitivity is, however, set by the time variation of anisotropy signal from the shaft and empty specimen holder. This limit is at 1.5 × 10−9 mksu (1.2 × 10−10 emu/cm3), so that relative anisotropy of 0.01% can be detected in a weakly magnetic sandstone of bulk susceptibility 1.5 × 10−5 mksu. Calibration is discussed and sample measurements are presented. Construction of the transducer required solution of many technological problems, of which the greatest was encapsulation to suppress all vibration of parts without strain-induced loss of permeability of the permalloy. The more important of the solutions found are outlined briefly.

Three dimensional magnetostatic field calculation using equivalent magnetic charge method

1991 ◽  
Vol 27 (6) ◽  
pp. 5010-5012 ◽  
Author(s):  
Y. Xu ◽  
Z. Jiang ◽  
Q. Wang ◽  
X. Xu ◽  
D. Sun ◽  
...  
Keyword(s):  
Magnetic Charge ◽  
Three Dimensional ◽  
Field Calculation ◽  
Magnetostatic Field
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