Questions tagged [electromagnetism]
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Controlled oscillation of a piano string by electromagnetic, mechanical, or other means
What would be a good way to actively control the loudness of an acoustic piano note over time after the note has already been struck by the hammer, such as by actively changing the amplitude of a ...
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Any information on magnetic braking with copper?
I have an engineering project where I have to design and build a model of a drop tower from a theme park. The tower itself can be no taller than 40cm.
I plan to use magnetic braking with copper to ...
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Braking system for a miniature ‘Drop tower’ rollercoaster
The tower itself is only max 400mm.
Designing the lifting system isn’t the problem but slowing down the gondola is posing a slight problem, any suggestions?
I have looked into using magnets but I can’...
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Accelerate an object in a current-carrying coil
I'm currently trying to come up with some concept ideas for a physics game / riddle. The player has to get an object from one side of a horizontal, current-carrying coil to the other end of the coil ...
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What would be the best capacitor to use for a railgun that uses a capacitor as the projectile?
I have had a long-time interest and fascination with railgun technology and for a long time I have wanted to build a small-scale, simple railgun as a scientific experiment. This railgun is designed to ...
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Viability of bladeless wind power generation
I have recently thought of two designs for bladeless wind power generation;
And
They both essentially ionizes the incoming wind which then passes through a coil, the flow of charged wind particles ...
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How does resistivity affect the susceptibility of a steel alloy to induction heating?
For context, my question is related to the use of heating to elongate studs for casing tightening and loosening. In turbine casing assembly, in addition to torquing the nuts, studs have holes drilled ...
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Why are the indices of term of the Cauchy Stress Tensor and Maxwell Stress Tensor opposite to each other?
For CST (https://en.wikipedia.org/wiki/Cauchy_stress_tensor), the first index represents the plane and the second index represents the direction:
For MST (https://en.wikipedia.org/wiki/...
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How to manufacture Inrunner BLDC motor core
I need to make a 10 slot BLDC inrunner motor core that is 40mm wide has 10mm inner diameter and 10mm thick. How would I make this? I would want to make it out of mild steel but I do not have a CNC ...
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S-Parameters and Received Power for Implant Antenna
I am simulating an implant antenna using the Ansys HFSS EM simulation tool - the simulation setup looks something like this, with a transmitting (TX) antenna of transmit power $P_{TX}$ and transmit ...
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Design of a 3 Phase Linear Induction Motor
I am a Mechanical Engineer but need to use a 3 Phase Linear Induction Motor (LIM) for a MagLev project.
To demonstrate the working of LIM I need to design LIM for accelerating a 10 kg payload to ...
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How can I transmit the force induced by magnetic torque?
So I'm working on a project where I'm trying to transmit the force induced by magnetic torque onto people's hands, thereby making it a haptic feedback system. This is the stucture that I designed to ...
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How is this Solenoid made?
I ran into this old YouTube video. As you can see apparently it's a solenoid, but the person doesn't explain how it's made. I've never seen a solenoid with such a long stroke, if you can please ...
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Wireless Power Transfer Modelling
I am trying to develop an analytical model for RF wireless power transfer from an external antenna to an implant antenna, embedded inside layers of lossy tissue.
The external antenna will be ...
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How does the magnetic field in a synchronous machine with two pole-pairs distribute if I only apply DC-voltage on two phases? (Star connection)
I am struggeling to understand the following:
If I consider a synchronous motor with only one polepair and apply dc-voltage to two of the three phases this results in a static magnetic field.
The ...
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How can I keep a low voltage electromagnet on continuously for long durations of time?
Background
I have an application that requires an electromagnet (either 5v or 12v) to be powered on for long durations of time (up to a few hours). While looking for one online, I was having a hard ...
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Mathematical Modelling of Wireless Power Transfer
I am trying to understand the interaction between a transmitting antenna with a certain transmitting power (denoted PTX in the diagram) and how the radiation pattern of the TX antenna is affected by a ...
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Conceptual relation between stepper motor and strain wave gear?
I've been looking at combined gearboxes with a stepper motor and strain wave gear, and at some point, I started wondering if they actually share a fundamental operating principle. In a strain wave ...
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Physics behind a realistic and theoretical DC motor
I am learning about theoretical DC motors where the rotational motion is produced due to torque on either side of a coil.
However, after researching real DC motors it seems to me that the winding ...
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Force applied on a ferromagnetic shaft by a coil
I have a perfectly cylindrical ferromagnetic shaft (say, made out of iron). I want to apply an axial force on the shaft (along the centerline of the cylinder) using a coil through which an electric ...
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I have 2 questions i am not able to solve in applied electromagnetics
I will attach the photos of the questions, it was my quarterly test paper
Consider a continuous line charge distribution along the circumference of a circle of radius 1 unit in the xy plane. With the ...
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How should one wind the coils for a BLDC motor to maximize torque, if nothing else matters?
I'm trying to build a brushless DC motor with six winding arms, pretty typical design. If I'm trying to maximize the torque output of my motor, what would improve the motor best:
Extending the length ...
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Recent breakthrough on Inertial Confinement Nuclear Fusion at NIF
For the very first time, it has been demonstrated that it is now possible to make Nuclear Fusion generate more energy than is required for its equipment to operate, but it is not entirely clear as to ...
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How to make the magnetic field intensity from a DC electromagnet bigger without changing its current, number of turns, or geometry?
I'm currently doing a project on magnetic haptic feedback using DC electromagnet. The principle of my haptic feedback system is very simple (figure shown below):
A permanent magnet is stuck to the ...
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How to concentrate magnetic fields using the least amount of material possible for a fixed area
So the goal is to a build a device that will redirect field lines from earths magnetic field at the magnetic north pole into a point.
The goal is to maximize the area / amount of magnetic flux ...
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Any scientific research papers on electromagnetic active valves using variable viscosity electromagnetic fluids?
I know the title is quite a mouthful, but let me explain (also, I couldn't find anything on the subject, maybe because I'm using the wrong words).
I saw some time ago a video about a variable ...
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What are possible applications for room temperature superconductor requiring extreme presssure?
At standard room pressure, the highest temperature superconductor is "the cuprate of mercury, barium, and calcium, at around 133 K" (-140 °C).
If pressure can be increased, however, the ...
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How to calculate voltage change across electrodes in tank of water?
Reposting from https://physics.stackexchange.com/questions/736554/how-to-calculate-voltage-change-across-electrodes-in-tank-of-water because apparently this is an engineering question and not an ...
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Which is the better magnetic arrangement for a voice coil to give a larger amplitude of movement all else being equal?
Given everything else equal (e.g. same overall amount of magnetic material, same strength magnetic material, same coil, same power supplied, etc. etc.) which of these two magnetic configurations of a ...
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Is Poynting flux the same as the Poynting vector?
I need to solve a homework question that asks me to find the Poynting flux. However, I can't find any formulas for Poynting flux anywhere. Is the Poynting flux the same as the Poynting vector?
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Does improper loading of a dynamic microphone cause damping or affect the coil movement?
Slightly struggling to find the right technical language to frame my question, but let me try...
A dynamic microphone is effectively an electrical generator, similar to an alternator.
I've read that ...
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How do I draw a circuit for a conducting loop inside a solenoid?
To solve a homework problem, I need to redraw the following diagram in circuit form.
The large blue circle represents the solenoid. Inside the solenoid, the two gray semicircles represent a wire loop,...
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Could electromagnets ever compete with the power of an antimatter annihilation engine? [closed]
So to make this easier to read, I've been using a few terms I'll explain really quick
"MPP": (maximum physical potential)
"MASS": (maximum atomic structure strength)
According to ...
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Why do inorganic LEDs wear out?
Why do inorganic LED bulbs have a limited lifespan? For example, a manufacturer may quote that a bulb or monitor powered by an organic light emitting diode(s) has a lifespan of 50,000 hours, while it ...
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DC Motor Powered Car
So I run an engineering class even though I mostly just do theory myself, so when it comes to actually building stuff I miss some basic ideas I should know.
I am having them make a DC motor out of a ...
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What is the smallest possible focusable, scaleably intense laser design?
Would anyone here have any ideas towards what the smallest possible laser mechanism across all physical potential might be? I was wondering this for a theoretical machine capable of manipulating ...
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Electromagnetism - DC Motor Design Question - EMF/BACK EMF
I'm not gonna lie - I don't have enough knowledge about EMF and Back EMF so I need you guys , my friend will soon build a DC motor for me but I currently have no idea what design will produce high ...
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Do infrared heaters have a special blackbody radiation specturm?
There are many infrared heaters on the market, that I would put in 3 categories, filament in quartz tube, filament in ceramic, and carbon film (for flat panel heaters).
They all claim to be "...
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Does the aspect ratio of an electromagnetic coil affect the efficiency of magnetic coupling to a magnetic core?
Let's imagine we have multiple different sizes of magnetic coils, however they all have the same number of turns and use the same gauge of wire. They all share the same geometry for their magnetic ...
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What are design considerations for an RCS test range be relocated fully underground?
Sites like the Lockheed Helendale RCS or the Tonopah test range are only known to have an underground pit to support raising or lowering of test articles. But is it technically possible to have a ...
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Could large electromagnets be used to stop active shooters? [closed]
I was thinking that a powerful set of electromagnets in high risk doorways could be used to stop active shooters. By placing them in doorways. The magnet size could be mitigated. Also, they could be ...
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Does an iPhone on airplane mode continue to emit electromagnetic radiation field?
I've been told that it does because it's still searching for networks or something, which doesn't really make any sense to me. But what does fit somewhat with that are notices in the android interface ...
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Is there any way to relate the induced EMF from an alternator to the DC current that is used in the field winding?
I'm trying to simulate the open circuit saturation of an alternator. Basically, by changing the amount of current that is going through the field windings (rotor), the voltage induced in the armature ...
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In a AWD Tesla Model 3, why is the front and back motor different?
In a AWD Tesla Model 3, why is the front motor (OEM 1120960-00-E) different from the one in the back (OEM 1120980)? Why not just use the same one for both front and back? I'm sure that there was a ...
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What are some methods of converting electricity without the use of induction or heat?
I was trying to study exactly how current in a wire is used to do so much in our life and how the energy is converted. But the only methods I have found are by using the resistance of the conductor to ...
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Faraday's law applied to a coil in an electromagnetic field
According to Faraday's law,
we have the law:
where "e" is the electromotive force which is equal to the derivative of the phase of the vector "b" through the surface s of the loop ...
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Superconductor Magnetic Field Limit
Not sure if this is a question for the engineering or physics stack exchange:
The current maximum magnetic field for a nonpulsed magnetic field is around 45 Tesla while pulsed is around 100 Tesla. I'm ...
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BH Curve of ST52.0 - S355J0 [duplicate]
I need to BH curve of ST52.0. Could anyone help to me?
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Angle of incidence in concave mirrors [closed]
What happens when you change the angle of incidence(normal to the mirror)? How does the angle of reflection change? Is it invariant?
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Magnetising a needle with static electricity using silk cloth
A nautical navigation textbook on my table says that we can magnetise a non-magnetised needle by rubbing it with a silk cloth. I decided to cross check on the internet, and found some experts calling ...
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