- What is eddy current and how it is produced?
- How does eddy current NDT work?
- Is eddy current used in electromagnet?
- What causes eddy current loss?
- What will you do to reduce hysteresis and eddy current loss?
- What is eddy current used for?
- What is the principle of eddy current?
- How often should eddy current testing be done?
- What is an eddy current in a river?
- What is meant by eddy current loss?
- Are eddy currents useful or harmful?
- What is the difference between hysteresis loss & eddy current loss?
- Does Eddy Current give shock?
- What is the disadvantage of eddy current?
- What causes an eddy?
- What is the difference between eddy current and induced current?
- Who discovered eddy current?
- Can eddy current detect cracks?
- Are eddy currents AC or DC?
What is eddy current and how it is produced?
Eddy currents are currents which circulate in conductors like swirling eddies in a stream.
They are induced by changing magnetic fields and flow in closed loops, perpendicular to the plane of the magnetic field.
Like any current flowing through a conductor, an eddy current will produce its own magnetic field..
How does eddy current NDT work?
Eddy current testing is based on the physics phenomenon of electromagnetic induction. In an eddy current probe, an alternating current flows through a wire coil and generates an oscillating magnetic field. … This in turn affects the movement of electrons in the coil by varying the electrical impedance of the coil.
Is eddy current used in electromagnet?
Electromagnetic braking Eddy current brakes use the drag force created by eddy currents as a brake to slow or stop moving objects. … Using electromagnets, as opposed to permanent magnets, the strength of the magnetic field can be adjusted and so the magnitude of braking effect changed.
What causes eddy current loss?
Eddy current losses are the result of Farady’s law, which states that, “Any change in the environment of a coil of wire will cause a voltage to be induced in the coil, regardless of how the magnetic change is produced.” Thus, when a motor core is rotated in a magnetic field, a voltage, or EMF, is induced in the coils.
What will you do to reduce hysteresis and eddy current loss?
hysteresis loss can be reduce by using material having least hysteresis loop area. hence silicon steel or high grade steel is used for manufacturing of a transformer core as it is having very less hysteresis loop area. you can laminated the core.
What is eddy current used for?
Non-Destructive Testing (NDT) Eddy currents are used in one of the most common electromagnetic NDT methods to see if a material or surface has any discontinuities, cracks or faults without damaging the material itself.
What is the principle of eddy current?
The eddy current method is based on the principle of generating circular electrical currents (eddy currents) in a conductive material. This is achieved by the use of a coil connected to an alternating current generator driving an alternating magnetic field (primary field).
How often should eddy current testing be done?
every 3 to 5 yearsIdeally, eddy current testing will occur approximately every 3 to 5 years, possibly more frequently if there is active damage occurring that should be monitored. Including eddy current testing into an annual inspection ensures that testing occurs with the proper regularity.
What is an eddy current in a river?
An eddy is a circular current of water. The swirling motion of eddies in the ocean cause nutrients that are normally found in colder, deeper waters to come to the surface.
What is meant by eddy current loss?
Eddy current loss is conductive I2R loss produced by circulating currents induced in response to AC flux linkage, flowing against the internal resistance of the core.
Are eddy currents useful or harmful?
This magnetic field of the coil can then be used to generate electrical current in another conductor. These electrical currents are called eddy currents because they travel in circles like eddy currents in a stream. … You should also be aware that electricity can be very dangerous.
What is the difference between hysteresis loss & eddy current loss?
The most significant difference between the Eddy current and Hysteresis loss is that the eddy current loss occurs because of the relative motion between the conductor and the magnetic field. Whereas the hysteresis loss occurs because of the reversal of the magnetism.
Does Eddy Current give shock?
Because we dont get shock due to current. We get shocks due to voltage difference between the conductor and ground. In case of eddy current voltage difference is very small so we dont get any shocks.
What is the disadvantage of eddy current?
Very susceptible to magnetic permeability changes. Small changes in permeability have a pronounced effect on the eddy currents, especially in ferromagnetic materials. This makes testing of welds and other ferromagnetic materials difficult but, with modern digital flaw detectors and probe design, not impossible.
What causes an eddy?
An eddy is a section of circular current that tends to flow in the opposite direction from the main river current. Eddies are usually caused by an obstruction in the river, such as a rock or fallen tree.
What is the difference between eddy current and induced current?
Induced current would be the current that results in a conductor due to a moving magnetic field. … Eddy current is when the induced electrical current then generate their own magnetic moments in that conducting core. These magnetic moments oppose the source magnetic field.
Who discovered eddy current?
Léon FoucaultFrançois AragoEddy current/InventorsThe phenomenon of eddy currents was discovered by French physicist Leon Foucault in 1851, and for this reason eddy currents are sometimes called Foucault currents.
Can eddy current detect cracks?
Eddy current allows analysts to inspect materials on a surface and near-surface level. … The best eddy current instruments can detect cracks for complex inspections like tubing via multiple frequencies and dual options, and can pick up developing cracks as small as 0.1 mm or less in depth.
Are eddy currents AC or DC?
The currents don’t flow back to the source. They dissipate their energy in the form of heat. And since the circuit is technically open, it can neither be called AC or DC.