Eddy current Definition and 77 Threads

Hello everyone, I try to calculate brake force for primitive eddy current brake, but I have problem with determining the frequency (skin depth) and characteristic length (magnetic Reynolds number). I attach the equations and a scheme of the model.

TL;DR Summary: How to calculate induction heat flux (density) induced by an infinitely long wire in an infinitely large slab. Hi, I have to simulate induction heating caused by a straight long wire in a thick slab of material (no strict limitations). To make it, in the best case I should...

I read this explanation on the Wikipedia entry for "eddy current brake". Let me go through the reasoning there. We have the metal sheet ##C## moving to the right under the magnet. For the parts of the sheet moving toward the magnet, the magnetic flux from the magnet is increasing. From...

Hello everyone, I'm working on a home project to create AC current, using magnets (AC Generator). I understand the principles of how to generate AC current however, I lack the complex knowledge of the physics side. I have searched and watched various Youtube videos etc, but none of them answer...

When you try to create time varying magnetic fields in solid metals, there is severe heating due to eddy currents, when you increase the frequency, just like in NDT(non destructive testing) the magnetic field is pushed away from the core to the periphery due to eddy currents opposing the field...

I started a project, and where I thought I has a potentiometer position feedback, best I can tell I have an eddy current position sensor, which I'm absolutely not familiar with The application is a diesel engine injector pump (retrofitting to a different engine, it was from a Komatsu V12, no, I...

Hi guys, The purpose of this post is to understand the actual phenomenon behind torque production in eddy current motors. This query is based on theoretical principles of torque production in AC motors. Consider a simple eddy current AC motor with a disc type or cylindrical rotor (Watthour...

Apart from the trivial elements of the motion equation (m z'' = -kz -mg), I am required to find the force produced by the Eddy currents induced by the moving magnet. To do so, I calculated the magnetic flux through the hole plate: For a magnet: Bz=μo m 4π. 2z^2−r^2/(z^2+r^2)^5/2 so Φ = a→ +∞...

All the equations I have seen have a component that is unknown. Also, if possible do let me know if there is a software I can use to model or analyze data related to eddy currents

So I've been trying to figure out how EMF shielding works. More specifically, I've seen videos where placing a metal conductor in front of a circular coil (with AC running through at radio frequencies) apparently shielded anything behind it. After searching online, I repeatedly saw Eddy...

My explanation: A circular coil is connected to an AC supply at a frequency of 30-50 kHz (radio frequency). Therefore, an alternate current will be running through this “primary” coil, producing an alternating magnetic field. This magnetic field periodically decreases in strength, alternating...

I know only about Laminated,Iron and wooden coil.I don't know what is Air cored coil. So according to me,it should be Wooden cored coil because less current will flow through wooden cored coil.Ans it will be maximum in Iron cored coil. Please tell,am I correct or not?I don't know the answer.

Hello there! I have seen some great eddy current brakes and wanted to learn more about it. The problem in the internet I can not the specific case I have in mind. I searched the internet and found a great deal of material about magnetic forces. I cannot, however, find the specific case I'm...

Homework Statement: Finding the braking torque applied on a moving disk as a result of the Eddy Currents Homework Equations: $$F = \sigma v V B^2$$ So right, Basically my problem is how to find the torque exerted by an eddy current braking setup. My setup consists of a disk rotating on an...

Hi, guys, I am developing a simulation in Ansys Maxwell. I set up my simulation in the "transient mode", and I would like to evaluate the eddy currents that arise in a metal Vessel. The currents rise to a flat top in 20 ms and then after 20 ms in the flat top, it decreases to zero in 20 ms. I...

I’m using an inductive heater to try to melt some 99.85% polycrystalline silicon, as would occur in the Czochralski process, but the silicon workpiece is not melting let alone even getting hot. The silicon workpiece is about the size of a playing dice. It becomes conductive at 200 F and becomes...

I've seen a documentary about the Yukon Route Railroad. Some trains are run by old steam engines (with Diesel). They also equipped their engines with eddy current brakes and said, that the resulting current is conducted into resistors and via thermal energy removed into air. I assume that...

Are both magnetic fields emanated from an electromagnet fed with a current spike from a charge capacitor and a rotating static magnetic field from permanent magnets instances of time varying fields? The permanent magnet would be attached to perhaps some rotating disc thus passing over a target...

I’m using a zvs inductive heater to try to melt some 99.85% polycrystalline silicon, as would occur in the Czochralski process, but the silicon workpiece is not melting let alone even getting hot. The silicon workpiece is about the size of a playing dice, and becomes fully conductive after...

Suppose a 10k Gauss 3in diameter sharp magnetic field is made & collapses completely thru a standing human human body somewere made by an external electromagnet.. The electromagnet is held horizontally and not vertically against body. Is this hazardous? Can it become hazardous after some...

Trying to create an experiment that utilizes a motor driven shaft to measure the angular velocity of another shaft via eddy currents. We made a mock experiment that uses 8mm shafts, pillow bearings, and ceramic magnets from home depot, but don't see a torque on a non-ferrous metal attached to a...

Hi, I've seen many videos of neodymium magnets sliding slowly down an inclined copper plate, or slowly down a copper tube - due to eddy current braking,but never the other way around. My question is; will a copper disc sliding down an inclined magnetic plate, or down a magnetic tube act in the...

Hello, I have four questions. As it stands now, I don't have the necessary materials to test this myself, which is how I'd prefer to learn the answer. I still plan on doing this experiment for fun once I can acquire the necessary components. This deals with Lenz's Law. My goal is to maximize...

I'm trying to use a solenoid to measure the magnetocaloric effect of dysprosium. The effect is highest at the Neel temp which is down near 180K. I have a solenoid in a cryostat to get the correct temperature. The cryostat's heat exchanger is made of a thick copper cylinder and I think it is...

In my lab we are working with a Coaxial coil and stainless steel tube, and are aiming to find the mutual Inductance. I've done some looking around and have easily found the Inductance of a Coaxial cable, and for that of Coaxial coils, but am having trouble with a combination of the two. The...

I am trying to simulate a linear eddy current brake. To do this, I am modeling my brake as a single magnet moving above an aluminum plate. I plan to measure the drag force on this magnet and calculate my braking force as a superposition of single magnets. Here's my current setup: Model: A...

Hi everyone - here's a concept that I'd like a few opinions on: As part of a project, I'm looking at using a brushless DC motor mounted on a high-speed vehicle as a generator. Once the vehicle hits its top speed, the batteries should disconnect from the motor and the vehicle's own velocity will...

For a microscale electric generator (where the driving force is a fraction of a Newton), can losses from eddy currents be significant enough to noticeably alter the rotational velocity of the rotor? Because my understanding is that the rotation is basically taken as a constant when examining the...

Hi all, I'm currently working on eddy current brakes designed to stop a vehicle from speeds around 135 m/s. While researching eddy current brakes, I found the equations used to find the force generated tend to break down at higher speeds. The design is linear, stopping on an aluminum rail...

Homework Statement I have a really simple question, state two types of eddy current couplings and state a flexible coupling, but I've been googling it for the last half an hour and can't find an answer. The Attempt at a Solution Can anyone tell me two types of eddy current couplings? I know...

Hey ! Let's say I have a solenoid that is only half-filled with a magnetic core. Now I want to know what is the loss due to Eddy currents. First, I want to find the magnetic field with Ampere's law. With this kind of geometry, I'm not even able to apply Ampere's Law ! have of picture here of the...

Hi. This is from a high school textbook, in a chapter about eddy currents and Lenz's law. In a), a magnetic field is turned on, in b) it's turned off, which both induces a current in a suspended aluminium ring: I think the direction of the current is wrong in both pictures. Any opinions?

hi, I really wonder ıs there a equation related to force generated by eddy current? And ıs there a derivation of this equation? I am asking because the only thing I can find is the eddy current density equation, no force formula exist on internet.

Hey guys, So I'm interested in the application of an eddy current brake system as a high intensity shock absorber of some sort. The system would consist of permanent magnets concentrated on a stationary, non ferromagnetic metal. If a sudden, intense force were to act upon the non ferromagnetic...

This question is primarily regarding transformers, particularly the impact frequency has on hysteresis loss. Given hysteresis loss = η×Bmax×f×V and Bmax = (V ×〖10〗^ 8)/(√2 π×f×N×A) This means that hysteresis loss = η (V ×〖10〗^8)/(√2 π×f×N×A) fV = (η ×〖10〗^8)/(√2 π×N×A) V^2 And as such...

Hi, i am an student of civil engineering and i am doing my graduate thesis. so sorry if i misspell, english is not my native languaje. so, here we go :D Homework Statement Before entering in details you (whoever you are) most know: The system is scaled for obvious reasons. The system consists...

Homework Statement There is 4 neodynium magnets. It is 0.7 inch magnet. A 15,000 RPM motor. It does not hover. I am trying to make a eddy current to make it hover1. The attempt at a solution Getting a copper plate, having a better magnet.

Hi. My colleagues and I are doing a research on transformers (single-phase) and we stumbled across the following equations involving hysteresis and eddy current losses: Wh = ηBmaxxfV where Wh = hysteresis losses η = Steinmetz hysteresis constant Bmax = maximum flux density x = constant...

Hi I am building a motor tester, for that I need to build a variable load. For which I was planning to use eddy current brake with electromagnet. Please help me to build a electro magnet which can provide more than 10mNm load to a DC motor with rotating disc of 75mm in a RPM of 6500. I tried...

In transformer, lamination is an effective method to minimize eddy current and thus energy loss. I just wonder how can we show that the energy loss due to eddy current in those laminates is added up to be less than that without lamination (suppose the total cross sectional areas are the same)?

Hi, I am working on an experiment to investigate the effect of electrical conductivity of the metals on the levitating force produced. Basically the concept is this: when a metal plate is placed on top of a solenoid (but not touching), as the a.c. flows in the solenoid the change in magnetic...

I am having difficulties writing my damped oscillations lab report. We were asked to write a short essay on eddy currents (creation,direction advantage and disadvantage) and their relationship with torsion pendulums. Also,we have to explain if the copper wheel in the torsion pendulum could be...

is skin effect of ac due to eddy current?

Hello I am a graduate Mechanical Design Engineer who was recently offered a job (through a graduate scheme) at a company that develops Recycling and waste management systems. As part of this I have to design and develop an new eddy current separation system so that the company can build the...

Need to refresh my understanding on eddy current. Does every metal exhibit eddy current when it comes across a Mag field? If this is the case, then why do induction cook tops required ferrous utensils. A Metal detector also works on the principle of eddy current. correct?

Hi all i hope some one can help but i have a feeling there will be no easy calculations for this one:confused: Im trying to calculate actual eddy current losses in 50hz mains transformers depending on lamination sizes and can't seem to find any info on the subject that's sub electrical degree...

Hello All, I have been asked to design and build a rig that will introduce the concept of a mass spring damper system to mechanical engineers in their early years of university. To make it slightly more complex, the rig needs to be torsional rather than linear. My design so far is to use a...

Dear All, How laminated core helps in reduction of the eddy current? How reduction of area is useful in reduction of eddy current? Thanks.

I'm trying to damp an oscillating metal plate with a neodymium magnet. Things I know - Remanence of the magnet - The magnetic flux density at distance z (from the distributors site) - Dimensions of the magnet - Plate material (Aluminium) - Distance to the plate. What I'm trying to find out is...

Hi, I have been trying to understand eddy current loss in transformer cores but seem to have run into a bit of a misunderstanding with one of the books I have read, and I was wondering if someone could just clarify if I have got this all right. starting with the beginning, if the magnetic...