Eddy Current Slots



Eddy Current Slots

CurrentEddy current spot size

Similar to structure testing, this type of eddy current test compares a known good part with a thread or feature under test. If the two are different, the eddy current instrument signals an alarm condition and the suspect part can be sorted out. Eddy current thread and feature testing offers many advantages over other inspection methods.

Eddy Current Slots Jackpot

Eddy current loss formula
  • We produce and distribute Eddy Current Test Instruments and Systems for the North/South American and Global NDT market.

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. Finally, the power loss is determined from the resistance and the eddy current of each ring. When the induced current leaves the magnetic field, again current will be induced but in the opposite direction. This effect of induced currents together gives the effect of eddy currents. Because of induced current the motion is dampedas they are opposing the motion of the plate. Metal plate with slots: In presence of magnetic field: Damping.

  • For more than 40 years we have been developing, producing and marketing eddy current instruments and systems for testing that are in use around the world today in crack, heat-treatment, positive material identification, and grinding burn tests. Testing solutions for every problem and every need. Made in the USA and Germany.

  • Custom solutions based on research and innovation. Close collaboration with leading labs, technology partners and in fields of applied research make it possible to develop a completely new generation of testing instruments. We use the latest components, specially developed materials, and systematically developed technologies. ROHMANN is a supplier of the most advanced and powerful testing instruments and systems currently to be found on the market.

  • How can we help you? We will be glad to assist you with any specific questions you may have. Simply contact us and make use of our search system or inquiry form.

Products News:

ELOTEST PL600 – The most avanced Eddy Current Test Instument

  • Maximum stability with unsurpassed signal purity for best results with classical eddy current and harmonic analysis
  • Suitable for all types of eddy current testing: Crack, heat treatment, material mix-up and grinding burn testing
  • Maximum test reliability through comprehensive system and sensor monitoring
  • Application-specific user interfaces for simplest operation
  • Full integration through extensive I/O functions with fieldbus connection
  • Modular design allows flexible expansion with easy maintenance

Products News:

ELOTEST PL600 – R/RC

Precise material sorting and high-resolution crack and grinding burn inspection

ELOTEST PL600/Remote, 19“/4HE

Eddy current spot size

ELOTEST PL600/Remote Compact, 19“½/4HE

The innovative, fully digital eddy current platform for integration into automated systems

  • Used with PC software under Windows or Linux or with HDMI+USB connected touch display or standard display with mouse
  • Including one universal test channel module with basic license
  • PL600/R, fullsize 19” rack with 15 free slots for additional modules
  • PL600/RC, half size 19” rack with 6 free slots for additional modules

Download the PL600 R+RC_2020 Fact Sheet (08-17-2020)

Eddy Current Loss Definition:


In this post we will discuss about various methods of reducing the Eddy current loss in the electrical equipment.
Before that we will get refresh about what is eddy current loss? and How the eddy current is produced?

  • The magnetic field surrounding a coil which is carrying AC current varies with time.
  • This varying magnetic field induces voltages in nearby conductive material like metal equipment cabinets, transformer cores and so on. The resulting current is known as Eddy current.
  • The currents flow in a circular manner like eddies in the brook, so they are called as eddy current.
  • They create unwanted power loss which is known as eddy current loss.
  • Additional power is required from the supply to make up this loss

Eddy Current Concept:

As shown in the figure, consider an iron-cored solenoid which connected to a supply via an on/off switch.

  • When the switch is closed, the current flows through a coil will increase rapidly. The coil current will reach to some steady value which will depend upon the coil resistance.
  • A magnetic field will be generated due to the flow of coil current.
  • The magnetic flux is proportional to the coil current and it will increase from zero to some steady value. This changing flux(dΦ/dt) expands outwards from the centre of the iron core.
  • As the flux linking with the core is changing, an emf will be induced in the core.
  • Since the iron core is a conductor, the induced emf will produce a current to be circulated around it. This is known as an eddy current ( it circulates similar to the manner created by an eddy of water).
  • The direction of the induced emf and eddy current will be determined by applying Fleming's right hand rule.

As the eddy current circulates in the core, it will produce a heating effect. This is normally an undesirable effect and is referred as eddy current loss. This loss is negligible in dc circuits as it will occur during circuit turn on and turn off duration only. But in AC circuits the eddy current will be flowing continuously, in alternate directions.

How to minimize Eddy Current losses?

  • In order to reduce the eddy current loss, the resistance of the core should be increased. In other words, low reluctance should be retained.
  • In devices like transformers, the core is made up of laminations of iron. ie,the core is made up of thin sheets of steel, each lamination being insulated from others.
  • As the laminations are thin, they will have relatively high resistance.
  • Each lamination sheet will have an eddy current circulates within it.
  • The sum of individual eddy current of the laminations are very less compared to that of using single solid iron core.
  • The eddy current loss is proportional to f2. So at higher frequencies, the eddy current loss is very high.
  • Under such conditions, the use of lamination sheets are not enough.
  • For this type of application, ferrite cores or iron dust cores are used. Using these materials, the eddy currents are limited to individual grains, so the eddy current loss is reduced considerably.

Eddy Current Loss Pdf


You may also like to read:
Comparison of Electrical and Magnetic Circuit
How Capacitor Works
Capacitor Types and Uses – Tutorial
Transformer Working Principle

Eddy Current Loss Equation

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