Questions tagged [electromagnetism]

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Linear solenoid mount

I have a linear solenoid with a tapped M3 hole at the end of the plunger, like this: I need to connect this plunger to a lever, so I want to add a mount which has a connection something like this: ...
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1answer
27 views

Use magnetic levitation to lift a carousel capable of turning 9000lbs [closed]

Allow me to describe my current situation. I have a 18 ft (5.486 m) carousel that is assembled using steel beams that are bent into two circles, an outer and an inner. And there are steel spokes ...
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1answer
29 views

Can you shape a magnet and how would it effect its field [closed]

Long story short im playing with mental designs of an electric motor and I'm not sure on some things regarding magmets/magnrtic materials and my designs are in flux do to these variables. I'm ...
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16 views

Calculate the temperature stability of wavelength demultiplexer

Hi ive been given this question: A wavelength demultiplexer (DMUX) used in a DWDM communication system has a channel spacing of 100 GHz. The operating pass band of each channel is 50 GHz. The ...
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1answer
59 views

Can waste heat in specific environments be collected into photons and converted to electricity?

This question is a repeat of another post on the physics board Here and here show the possibility to combine photons of lower energy to higher energy. Thinking of an application, it could be used to ...
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1answer
46 views

Ripple tank simulation for simulating light waves? [closed]

Can anyone help shedding some light on how ripple tanks are programmed? example I'm looking to simulate light waves, to perform theoretical calculations, as opposed to for just visual effect. The ones ...
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46 views

Is there an analogy between mechanical vibrations and electromagnetic waves

Recent questions about analogies between mechanical and electrical systems and about electromagnetic waves from a conductor made me wonder whether there is an analogy between the mechanical vibrations ...
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1answer
22 views

Is there a way to quantify the amount of radiofrequency interference?

Is there a way to quantify the amount of radiofrequency interference? Do any units exist that quantifies how much radiofrequency interference is there?
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3answers
72 views

What Goes Into Making a Variable Field Magnetic Motor?

(I feel it is necessary to mention that I am not an electrical or mechanical engineer; I just like to build fun things.) I've already got a good explanation of the concepts involved in a variable ...
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1answer
37 views

How could you produce large quantities of metallic hydrogen?

Could you somehow crush hydrogen atoms with magnetic fields in order to produce it? Or maybe someday someone will invent a material capable of withstanding 500GPa and we'll have giant machines that ...
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35 views

DC and AC Simulation on Ansys Maxwell for calculating the core and winding losses in an Inductor

I want to simulate the core and the winding losses in an inductor using Ansys Maxwell when imprinted with a triangular pulse(positive RMS Current). I am doing a DC simulation to get the inductance ...
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2answers
23 views

Is VLF-EM scanning for fractures a valid way to find groundwater for a well?

I need to choose where to drill an agricultural well. I am trying to get as much water as possible (at least 100 gpm). I am considering hiring a guy who claims to be able to find water using a device ...
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11 views

In a rectangular waveguide, how can one determine if any propagation modes exist?

I'm currently studying microwave engineering, and I came across the query mentioned above. I know that rectangular waveguides use TE(m,n),TE and TM modes, but I do not understand how these modes came ...
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21 views

How is the simplest Ampere's law formula for cylindrical surfaces?

Current would only flow through the cylinder walls, not inside the cylinder. The cylinder is hollow. I need the formula in order to calculate the magnetic field produced and see if it's lower than the ...
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36 views

Solenoid with 3mm stroke and ~1ms response time possible?

I need to extend and retract a needle as fast as possible with dwell time while retracted, while one option I really like would be to use Scotch Yoke with dwell. However that would mean the stroke and ...
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12 views

Determining the magnetic reluctance of a straight flux path

Currently I run into an issue understanding the following. The bottom part of this magnetic circuit is made from steel which has a finite relative permeability. However, the flux paths is made out of ...
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1answer
74 views

Can be used a lab on a chip device as a nuclear fusion device? [closed]

This is what a lab on a chip is https://en.wikipedia.org/wiki/Lab-on-a-chip I ask if could be used as a nuclear fusion device , that could rise the number of nuclear fusion per atom, knowing that ...
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1answer
81 views

Why are the synchronous reluctance motors not self-starting?

I have been studying synchronous reluctance motor since a month. I am curious to know why is this motor not self starting? If used with an inverter, this motor can be made self-starting. Or by adding ...
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30 views

Utilizing solenoids in electric motors

I have seen videos of solenoid engines but there were claims that they were inefficient unlike DC motors. I was wondering what would be the most efficient use of a solenoid in an electric motor. ...
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1answer
62 views

Building oscillating magnetic field circuit

I wanted to create an oscillating magnetic field using an electromagnet which is rated for 12V continuous duty. I was thinking that I need an arduino to control the electromagnetic circuit by using a ...
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1answer
29 views

Why don't car manufacturer's use a combination of disc brakes and electeomagnetic brakes to reduce braking distances?

It many be due to costs or that the brake discs would have to be made out of aluminium/copper for the electromagnetic braking to be effective or there may not be a significant reduction in braking ...
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31 views

BLDC Motor underwater ; weird behaviour

I recently was riding my e-bike (with a bldc hub motor) and decided to cool the motor (it -the stator- was approx 100-150 celcius I think) in the river. The controller is on the top of the bike and ...
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1answer
38 views

Protect equipment against electromagnetic radiation [closed]

They say that in the near future high cosmic radiation is possible. In addition, the Earth’s magnetic field is likely to weaken. I want to create something like a camera that would protect against ...
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2answers
223 views

Why does this magnetic charger cause short circuit when it sticks to the metal leg of my table?

Recently, I have bought this product. It is basically a USB cable, with a magnetic end, and a tiny attachment that goes into the mobile device. I plugged it into my laptop cooling stand (which has ...
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165 views

Please explain this flatbed microwave design

Here is a Galantz flatbed microwave The waveguide is smaller than a wavelength. 1)Usually apertures of less than a wavelength are considered to block EM wave but not here, why ? 2)The width of the ...
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1answer
118 views

ElectroMagnetic Pulling Force fdropoff with distance

I am looking make a quick and dirty test ring using an off the shelf electromagnet. My force needs are small, less than a pound but I need to do so in a non contact manner. I know these magnets are ...
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41 views

DC motor Magnetic axis of armature winding vs EMF

When considering the cross section of a DC motor we have: I notice that the Magnetic axis of the armature winding is aligned with direction of the EMF that will cause the rotation. Is there a ...
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1answer
65 views

How do old wind turbine towers pickup magnetism overtime?

I was conducting some robotics tests on a old wind turbine today, and noticed strong magnetic fields around the steel tower. This magnetic field does not exist on other modern wind turbines at the ...
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2answers
209 views

How do maglev trains turn given that they seem to have more than two bogies per car?

All of the images of maglev trains that I've seen seem to have a continuous drive mechanism along the entire length of each car: I assume this must be articulated some how, or the train wouldn't be ...
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1answer
49 views

What emits more radiation, cell network or wifi?

I've researched in the Internet but can't find any conclusive answer. When will your phone emit more radiation, downloading 1 Mb of data from a cell network (3G, 4G) or downloading the same amount of ...
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36 views

Is there an inward (radial) force acting on a magnet inside a magnet?

With a magnet inside another hollow magnet, for example an iron rod in a hollow cylinder, the iron bar placed inside the cylinder with poles attracted to opposite poles of cylinder (likes repel ...
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2answers
116 views

In induction heaters why do metal pieces levitate in center of radial axis?

In induction heaters metal seems to levitate in center of radial axis, as well as longitudinal axis (see video). Is by any chance the reason for that like in this schematic, that magnetic field lines ...
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3answers
194 views

Are the magnetic field lines flowing from north to south _inside_ a bar magnet as well?

It seems based on the magnetic field of ring magnets like the magnetic field lines of a bar magnet actually runs from N to S also inside the magnet, yet schematic images tend to show the field lines ...
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1answer
161 views

Diametrically magnetised ring magnet, opposite poles on the inside?

I am wondering about the magnetic field on the inside of hollow magnets. As an example, will use a ring magnet. In a diametrically magnetised ring magnet, does the magnet have the same pole on the ...
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98 views

Are stator magnets in brushed DC motors radially magnetised?

In an electric motor like this one, are the stator magnets radially magnetised, as in, each of the two magnets has opposite poles on the inside and outside diameter?
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88 views

Can two-pole brushed DC motors have a ring magnet stator?

Is it possible to build a brushed DC motor with a ring magnet stator, instead of a stator with gaps as shown in the GIF below?
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1answer
49 views

What is the material requirement for Van der Graff generator sphere?

I would like to make a Van der Graff generator for my science fair project out of aluminized mylar. Do you think this might be feasable or do I need to use thick stainless steel ball? Is there some ...
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1answer
21 views

How to contain air ions inside a chamber without loosing their charge?

I would like to create an experiment where I would hold ionized air molecules. Most likely negative O2-1 ions. I am looking for the most appropriate enclosure so that the ions do lose as little of ...
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1answer
119 views

Can a Foucault's current brake be used on the rails themselves to brake trains?

Your typical Foucault's current brakes operate on a disk, which is placed in an electromagnetic field in order to transform kinetic energy into heat without friction. The problem is that the disk ...
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2answers
140 views

Is there a motor design where a rotor gradually moves into a stator?

I was wondering if there is a motor/generator design where the rotor moves gradually in and out of the stator along the axis of rotation, or the stator moves over the rotor. If so, I'd like some ...
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1answer
62 views

Magnetic treatment of hard water to prevent scale and corrosion? How does this work?

I ran across this company at their booth at a Tradeshow (2018). They claim to have a chemical free (and as far as I can tell - a power free) treatment method for hard water to minimize scale and ...
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2answers
125 views

Can you use an electromagnet to break the connection of a permanent magnet?

At first, I had a particular goal, but I'm starting to doubt feasibility which has led me here. Original Goal: Create a small (3in²) electromagnet with 100% duty cycle capable of holding at least ...
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1answer
73 views

Can magnetic stripes be read wirelessly with lasers or other technologies?

I know that magnetic stripes used in credit cards and audio tapes are typically read by a magnetic reader head. But is it theoretically possible for the stripe to be read by a laser in a similar ...
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1answer
32 views

Can a electromagnet find a tube underground?

I was seeing how an electromagnet could attract a car when it's destroyed, and I was wondering, because I have to find the water tubes in my house (20/40 cm depeer), if I can put a wire inside the ...
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18 views

Restricted Rotation using electromagnets

I was wondering if I could restrict the rotation of a part over another in one direction alone using an electromagnet but allowing me to have a continuous rotation if forced (maybe by using some ...
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38 views

Is it possible to protect electronics on a cubesat from 100-1000g of acceleration

I am currently researching the feasibility of setting up a coilgun that launches Cubesats for a paper.
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1answer
326 views

Difference between permanent magnet and electromagnet exciter generator in principles wise?

I searched about this, but couldn't find any helpful explanations. All it says is that magnetic field is generated by either permanent magnets or electromagnets. In both cases, how does the exciter ...
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2answers
45 views

DC relay relation with resistance

Is there any method or formula that can be used to find the operating voltage of a coil using the resistance of the coil? If so, is it also applicable to AC coils or any other technique?
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What are the strengths and limitations of the antenna design of the Montjuïc Communications Tower?

The Montjuïc antenna is an interesting design for an antenna. I presume the design is principally an antenna, but perhaps it is not? If the ring + mast is an antenna, how does the ring work to ...
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118 views

Method to simulate a dipole antenna in salt water?

I am looking to simulate the radiation pattern of a 2.7Ghz half-wavelength dipole antenna immersed in salt water. I've been using Altair FEKO software to try and accomplish this. I've tried two ...