Have you seen a speedometer inside your vehicle? In the speedometer, a small magnet is connected to the main shaft of the vehicle. According to the speed of the vehicle, it rotates. Due to the effects of the eddy currents, the motion of the rotating is opposed and the pointer gets deflected through a certain angle. The pointer attached to the calibrated scale indicates the speed of the vehicle.
Eddy Current Definition
Induced electromotive force is produced in the coil when there is a change in the magnetic flux linked with that coil. Eddy currents are named so because the current looks like eddies or whirlpools. When a conductor is placed in the changing magnetic field, the induced current in the conductor is termed as Eddy current. We can define it as:
Eddy currents are loops of electrical current induced within conductors by a changing magnetic field in the conductor according to Faraday’s law of induction. Eddy currents flow in closed loops within conductors, in planes perpendicular to the magnetic field.
Like Lenz’s law, there are lots of experiments done to explain the eddy currents. The first test showed that inside a solenoid a soft iron core is introduced and it is connected to the alternating electromotive force. When the metallic disc is placed over the soft iron core, the circuit is switched on and when the circuit is turned on the metallic disc is thrown up away from the iron core.
Primarily, eddy currents will be introduced in the material, when an electrically conductive material is placed in the coils magnetic field an electromagnetic induction occurs.
The magnitude of the eddy currents produces a large current since the resistance of the metallic conductor becomes low. They may produce undesirable effects if the large eddy current is allowed into the core of a choke coil, transformer, etc.
By making use of a laminated core, the eddy currents produced in the core of a transformer are reduced. In the present day, electric brakes are provided on the trains in addition to those vacuum brakes.
Frequently Asked Questions – FAQs
What is eddy current?
What is electromotive force?
The electric potential produced by either an electrochemical cell or by changing the magnetic field is known as the electromotive force.
How does the eddy currents look like?
What is the induced current in the conductor known, when a conductor is placed in the changing magnetic field?
What is meant by speedometer?
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