Questions tagged [magnetic-flux]
The sum normal component of a magnetic field passing through a surface.
2
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1answer
43 views
Parasitic Inductance
when we say that in a wire there is a parasitic inductance, what is its cause? Is it the skin effect of the wire, the magnetic flux (generated by the current) through the surface of the total circuit ...
0
votes
2answers
67 views
How do I convert the units of a moving magnetic field to volts?
Copper wire wrapped around an iron core produces current when a strong magnet is moved in its vicinity.
I gather the "magnet movement" part is expressed in units of "weber" (kg⋅m2⋅s−2⋅A−1) or perhaps ...
0
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2answers
53 views
What causes the residual magnetic flux when the current is zero in an inductor hysteresis curve?
An inductor with hysteresis has the following current versus flux curve:
I marked the point in red where the current is reduced to zero but there is still flux on the above curve.
What really causes ...
3
votes
2answers
91 views
Hall effect sensor as 2 wires switch
I need to find a way to make an on/off proximity detector triggered by a magnetic field, fitting in a small space of about 5mm ^ 3, and connected to the board by only 2 wires. I know a could use a ...
3
votes
1answer
99 views
What impact does winding tightly versus loosely have on transformer performance?
To make it simple (and actually, directly relevant to what I am working on): what impact does winding tightness have on transformer performance? Lets assume typical laminated EI / EE 60hz transformer, ...
0
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0answers
16 views
Inverse LUT of flux-linkage maps for PMSM
I've been given the LUT of the flux linkages for an IPMSM in the dq-domain.
\$\lambda_d = f_1(i_q, i_d)\\
\lambda_q = f_2(i_q, i_d)\$
The maps are obviously non-linear. The sampling has been done ...
0
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2answers
45 views
Determining magnetic flux density of a closely wound toroidal coil
I am using David K. Chengs's Fundamentals of Engineering Electromagnetics book. In chapter 5/question 5.2, there is a given closely wound toroidal coil, and it asks what is the magnetic flux density ...
0
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1answer
56 views
How can a magnetic circuit with an airgap have a higher e.m.f in the secondary coil than the same circuit without the air gap?
I have a magnetic circuit with the same configuration as in the image, the primary coil has 203 turns and the secondary has 406 turns, how do I get a higher eletromotive force when there is an air gap ...
1
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0answers
53 views
Estimate the Flux Linkage of a PMSM Motor
I'm not sure if it is possible to estimate the flux linkage of a PMSM motor (star connection) by the controller itself, where I can measure the input voltage, all the phase currents and the velocity. ...
2
votes
1answer
122 views
What is the purpose of perpendicular “smaller” magnets in between the main magnets in a rotor of a motor? had never seen this before. Do they help?
I am trying to build my own generator at home for fun, I saw on a video in youtube https://www.youtube.com/watch?v=YsSm65DAcCg where the guy placed smaller magnets in between the main magnets of the ...
-1
votes
1answer
108 views
What is the main difference between AC and DC generator basic working principles? [closed]
I cannot understand the main difference on AC- DC generator basic working principles.
Lets consider how a loop wire works with a magnetic flux inside a DC generator briefly. Whenever the sides of the ...
0
votes
1answer
29 views
Does a wider magnet mean less flux density?
I was using an online magnet strength calculator when I halved the diameter of the theoretical N52 magnet. The dimensions went from 32mm in diameter and 3mm thick, to 16mm in diameter and 3mm thick. ...
0
votes
2answers
91 views
Can I use rectified AC current to heat an object inside a induction coil?
The reason why I would like to use rectified AC is because I want to keep the magnetic field inside the coil unidirectional. A changing magnetic field induces current in the coil and vice versa. ...
0
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3answers
48 views
Magnetic field direction
How do I know the direction of magnetic field produced by a bar magnet, assume a electron present side to the magnet ?
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0answers
40 views
Scaling of magnetic field strength and flux density measurements and shape of hysteresis loop
Note: this is part of a larger question which I was asked to separate into subquestions.
Other subquestions: 1 and 2
I'm using the method outlined here to measure the induced magnetic flux density in ...
0
votes
0answers
39 views
Cutoff frequency of passive RC integrator used to measure magnetic flux density
Note: this is part of a larger question which I was asked to separate into subquestions.
Other subquestions: 1 and 2
I am using a passive RC integrator to measure the induced magnetic flux density in ...
1
vote
1answer
53 views
Buffering the input to a passive RC integrator used to measure magnetic flux density
Note: this is part of a larger question which I was asked to separate into subquestions.
Other subquestions: 1 and 2
I'm using the method outlined here to measure the induced magnetic flux density in ...
1
vote
2answers
81 views
Magnetic path length for partially wound toroidal transformer core
According to Wikipedia, magnetic path length is defined as "the effective length of a closed magnetic loop inside a magnetic core made of ferromagnetic material." Thus, for a toroidal core that is ...
-5
votes
1answer
140 views
Is there a difference between the radio magnetic field your body senses, from downloading 1 kB data from Wi-Fi router compared to 1 GB of data? [closed]
Imagine you have a Wi-Fi router and you're downloading 1 kB of data, if your body is receiving any magnetic field or signal from the router, what would be the difference if the router was sending 1 kB ...
0
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0answers
20 views
Problems in simulating current model flux observer
I want to estimate rotor flux in 3 phase induction machine using Blaschke's equations. Here's the current model I'm suppose to simulate.:.
I have to simulate this thing, I successfully obtained iqss ...
0
votes
1answer
34 views
90 degrees phase shifted magnetic fields
If we have a closed magnetic circuit with two primary coils and one secondary coil wound on it. The primary coils are wound such that unlike poles are adjacent. Both primary coils are using rectified ...
0
votes
1answer
57 views
Lenz Law and Magnetic fields in an Inductor
Hoping somebody can set me straight on the magnetic fields involved in an inductor when the current is changing. This is how I see it:
The source current has a magnetic field.
This changing flux ...
0
votes
0answers
37 views
PM Generator magnet and stator relation
I am designing a 3 phase axial flux permanent magnet generator. Howewer, I can not find reference or study of the optimal size of slot and coil, in relation to the magnet.
I am adding a picture for ...
2
votes
3answers
120 views
Why is the magnetic field around a bar magnet represented by iron filings?
Why would we use iron filings to display a magnetic field interaction and then teach this as the unaffected field of a magnet?
Iron affects the field itself. This is analogous to an observer ...
2
votes
4answers
431 views
Magnetic field strength and flux density from hysteresis curve
I am trying to measure the magnetic hysteresis curve of a toroidal nanocrystalline ferromagnetic transformer core made of Nanoperm (datasheet linked) using the following circuit. Each of the windings ...
0
votes
1answer
51 views
Is the conventional current direction assumed to be from - to + in US Air force training videos?
1)
https://youtu.be/a8casNPDvI4?t=354
I'm not sure if I'm misinterpreting, but I couldn't get past this point in the video as it seems they are assuming the current flows from - to + and its ...
0
votes
1answer
99 views
Can throwing charged capacitors cause magnetic fields?
Since current is just buckets of charge passing through a point in space per unit time, and a capacitor is a literal bucket of charge, I had some questions in mind.
Is throwing a charged capacitor ...
0
votes
1answer
58 views
Introducing third winding in Transformer
What would happen if I wind another winding (call tertiary winding with the same number of turns) on the transformer core and apply an AC voltage to it which is in phase with the primary voltage but ...
-4
votes
1answer
285 views
Maximum and Minimum flux in a coil [closed]
A coil of 100 turns and a diameter of 3.18cm is mounted on an axle through a diameter and is place in a uniform magnetic field, where the flux density is 0.01T, in such a manner that the axle is ...
1
vote
2answers
433 views
Metal detector coil SHIELDING?
Many designs of coils, of metal detectors, are shielded (Faraday shield).
Should this be used in a gravity-fed detector (like the sketched one)?
What's the shield for?
NOTE:
The coils are arranged ...
0
votes
1answer
57 views
Flux control in transformer
What would happen if I apply a voltage (same phase as primary) to a tertiary winding wound over the transformer core? Would the mutual flux change or would the primary draw a different value of ...
0
votes
1answer
142 views
When to use a Hall probe and when a fluxgate magnetometer to measure magnetic fields?
I am familiar with how the two methods work, but what applications are more suitable for one rather than the other?
I have seen this question but I don't think it covers my point.
0
votes
1answer
102 views
How does this dynamo work?
I disassembled a dynamo-fuelled torch and I found this set-up.
Now, what I know is that the led should be lighted up by the electromagnetic force generated by the time-varying flux within the coil. ...
2
votes
0answers
77 views
Flux control of transformer
Can the flux (not flux density) of a transformer be controlled so as to achieve constant voltage output with varied loads? For example, increasing the flux slightly when the load is high.
0
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1answer
150 views
Why my In-wheel BLDC Motor have sinusoidal back emf (line to line) when rotate by external system?
I have In-wheel BLDC motor having 46 poles (Permanent Magnet)on rotor and 51 slot in stator. When I used an external machine to rotate my in-wheel BLDC motor, then measuring across two phase back emf ...
1
vote
2answers
198 views
why in-wheel BLDC motor have more pole than normal BLDC motor?
I am using a In-wheel BLDC Motor having poles 46 but another normal BLDC motor have less pole as 8 pole. I have searched about other In-wheel BLDC motor and it also have 42 poles.
0
votes
1answer
100 views
Electromagnet flux density calculation knowing specs of coil, core and applied voltage?
Seems to be almost a textbook task from a freshmen class. But I am truly puzzled.
Electromagnet has a coil of tightly wound 100 turns of copper wire around a cylinder core with relative permeability ...
0
votes
1answer
114 views
What parameter is used to choose the direction of the flux in a magnetic circuit?
I don't get why the \$\Phi_{1}\$,\$\Phi_{2}\$ and \$\Phi_{3}\$ are supposed to be running in the way depicted here.
0
votes
1answer
40 views
Skin effect and mag field distribution inside an electric conductor
Magnetic field inside a current carrying conductor
Suppose I took a circular current strip in a current carrying wire. At the centre I have marked the directions of magnetic field due to four points 1,...
0
votes
0answers
388 views
how to calculate the forces between an electromagnet and the permanent magnet?
The electromagnet consists of copper coil wound on the stainless steel cylindrical hollow pipe with the outer diameter of 70mm and inner diameter of 50mm.
while the permanent magnet is of a ...
0
votes
0answers
46 views
magnetic field, resistance and inductance of the coil
i have a coil wound ready. I need to find the magnetic field, resistance and inductance of the coil. can someone tell me some simple circuits to find it? And how to find the field using a pickup coil?...
1
vote
1answer
83 views
Why the shape of rotor-poles of salient pole synchronous machines are designed as sinusoidal in shape?
I knew that this is done to eliminate harmonics. But I couldn't get its reason. So I am confused whether my conclusion was right or wrong.
1
vote
2answers
734 views
How can increasing the voltage/frequency ratio of an induction motor result in magnetic saturation?
The information below pertains to an induction motor:
The magnetic capacity of the motor's magnetic (iron) circuit is designed to the relationship: voltage/frequency (V/f). If the frequency ...
0
votes
0answers
58 views
What is the internal linkage flux of a wire with radius a(shaped like a cylinder)
How can we clarify that the relation between linkage flux an flux in a cylinder shaped wire is \$ d\lambda=\frac{x^2}{a^2}\ d\phi \$?can we illustrate this by electromagnetic formula?I think I would ...
0
votes
1answer
73 views
Measuring Low Magnetic fields
Im working on a project where I want to measure low magnetic fields in a wire. The range I want to measure is 0.1 - 10 mG or 0.01 - 1 µT in low frequencies (DC - 500Hz) (This range (0.1 - 10 mG) can ...
0
votes
2answers
100 views
Three phase induction motor
If speed of rotating flux and actual speed of rotor is same then what will be the torque produced in three phase induction motor and why?
2
votes
3answers
131 views
Lightning detection
I am planning to build a device that has a capability of early detection of a lightning. Also we want to measure the magnitude of the lightning and can anyone suggest a way to measure the magnitude of ...
4
votes
2answers
238 views
X-ray back-projection for conversion to hard-field magnetic induction tomography?
This is a question about hard-field back-projection as used in x-ray tomography, applied magnetic induction tomography (MIT). Al-Zeibak and Saunders (A feasibility study of in vivo electromagnetic ...
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0answers
498 views
Digital Compass and Magnetic Declination Angle
I have a digital compass of HMC5883L and I want to measure orientation with it. The doubt that arise is about the magnetic declination angle. From the definition of declination angle, it is the the ...
6
votes
6answers
908 views
Mechanism of transformer secondary current
When a transformer has the secondary open and it's driven by an AC source, the only current that the primary draws is the current needed to produce the flux to magnetize the core (like ferrite) of the ...
