Eddy current testing is a non-destructive testing (NDT) inspection method used for a variety of purposes, including for
flaw detection, material and coating thickness measurements
, material identification and establishing the heat treatment condition of certain materials.
What are the uses of eddy current?
The minor application areas where eddy currents are utilized include use in
energy meters
, automobile speedometers, induction alternating current (AC) motors, free-fall devices, as a way of detecting coins in vending machines, to increase temperatures uniformly in induction furnaces, and in proximity/displacement …
What is eddy current and its two uses?
-Electric power meters: Eddy currents
cause the rotation of shiny metal discs in the electric
power meter. Electric currents are induced in the disc by magnetic fields produced by alternating varying currents in a coil. -Induction furnace: Induction furnace is used to prepare alloys and produce high temperatures.
In what case is eddy current applicable?
Some Practical Applications
During braking
, the brakes expose the metal wheels to a magnetic field which generates eddy currents in the wheels. The magnetic interaction between the applied field and the eddy currents acts to slow the wheels down.
What are the applications of eddy current testing?
- Crack detection. …
- Tube and wire testing. …
- Condenser tube inspection. …
- Material sorting. …
- Weld testing. …
- Coating thickness measurement.
What is the disadvantage of eddy current?
Disadvantages of Eddy Currents:
There is a major heat loss during cycling eddy currents due to friction in the magnetic circuit
, especially where the core is saturated. Thus there is the loss of useful electrical energy in the form of heat. There is magnetic flux leakage.
What causes an eddy?
Eddies form
when a bend in a surface ocean current lengthens and eventually makes a loop
, which separates from the main current. … These are eddies. In this image, surface water is colored depending on its temperature. Cooler water is shown with blue and purple and orange and yellow show warmer water.
What is eddy current explain with examples?
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.
Does speedometer apply to eddy current?
These forces cause electrical current to flow in the cup in small rotating eddies, known as eddy currents. In some applications, eddy currents represent lost power and are therefore undesirable. But in the case of a speedometer,
the eddy currents create a drag torque that does work on the speedcup
.
How can eddy current be reduced?
Eddy current magnitude can be reduced by
designing the core as a set of thin sheets or laminations
, in parallel to the magnetic field. … Eddy currents can also be reduced by using a magnetic material such as silicon steel, with a higher resistivity.
Why are eddy currents undesirable?
Eddy currents are induced in any conducting medium in which the magnetic field varies with time. … These eddy currents can produce undesirable effects such as power loss, heating, and—
in magnetic recording—degradation in performance
.
What is meant by eddy current losses?
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
.
What is eddy current formula?
Next, the eddy current flowing in each ring is obtained by solving a complex matrix equation of the form
[X] [I] = [V]
where X is the impedance matrix, I is the eddy current matrix, and V is the induced voltage matrix.
Are eddy current useful or harmful?
They are
both, useful and harmful
.
What is the advantage and disadvantage of eddy current?
The advantages of eddy current testing are:
Sensitivity to surface defects. Able to detect defects of 0.5mm in length under favourable conditions. Can detect through several layers
.
What are the merits and demerits of eddy current?
Eddy current
converts the kinetic energy into heat
and this is applied in many useful applications like Magnetic Braking in trains, Electromagnetic damping, Induction furnace etc.In this process, there is a loss occur in this system to reduce this we need to increase the core resistance and there is more losses in eddy …
