What is eddy current loss in induction motor?
Eddy current losses (also called Foucault’s 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 create a magnetic field that resists the change of the magnetic field that created it.
What are the losses of eddy current?
The heat loss caused by eddy currents in the magnetic material is called eddy current loss. The circulating current caused by induced EMF is Eddy Currents. The heat loss caused by eddy currents is eddy current loss. The other loss in the magnetic material is hysteresis loss.
Does eddy current loss depends on current?
Detailed Solution. Thus, we can say that eddy current loss depends on frequency, flux density and thickness of the core.
Where does eddy current loss occur?
Eddy current loss in the transformer is basically I2R loss present in the core due to the production of eddy current in the core. Eddy current losses are directly proportional to the conductivity of core.
What is eddy and hysteresis losses?
In electric machines, a varying magnetic field causes eddy currents in all metallic parts and hysteresis in ferromagnetic core. The losses caused due to eddy currents are known as eddy current loss and that caused due to hysteresis is known as hysteresis loss.
How the eddy current losses can minimized in induction machines?
To minimize the eddy current loss we increases the resistance in the path of eddy current by laminating it. Eddy current losses are directly proportional to area of armature or more precisely the path of motion. In laminated armature eddy current losses are reduced to very less or ‘0’ quantity.
Is eddy current loss depends on voltage?
Therefore, Eddy Current Loss only depends on the applied Voltage.
Why eddy current loss occurs in a transformer?
Since the material is conducting, these induced voltages circulate currents within the body of the material. These induced currents do no useful work and are known as eddy currents. Eddy current loss in the transformer is basically I2R loss present in the core due to the production of eddy current in the core.
What is hysteresis current loss?
Hysteresis loss in a transformer occurs due to magnetization saturation in the core of the transformer. Magnetic materials in the core will eventually become magnetically saturated when they are placed in a strong magnetic field, such as the magnetic field generated by an AC current.
How can eddy current loss be prevented?
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.
What is eddy current loss and how do you Minimise it?
Eddy current magnitude can be reduced by designing the core as a set of thin sheets or laminations, in parallel to the magnetic field. Each sheet must be insulated from its neighbours with a thin coating of varnish or oxide film. By laminating the core, the area of each section and hence the induced EMF is reduced.
How can eddy current loss be reduced?
How are hysteresis and eddy current losses minimized?
The eddy current loss can be minimized by considering the laminated core. By using alloys like mumetal or silicon steel, hysteresis loss can be reduced.
How do hysteresis and eddy current loss depend on frequency?
At a constant V/f ratio, hysteresis losses are directly proportional to the frequency. Eddy current losses: Eddy current loss in the transformer is I2R loss present in the core due to the production of eddy current. At a constant V/f ratio, eddy current losses are directly proportional to the square of the frequency.
What is the difference between eddy current loss and hysteresis loss?
Difference between hysteresis loss and eddy current loss Hysteresis loss is caused due to molecular friction in a ferromagnetic material, under alternating magnetic field. Eddy current loss us caused due to the induction of eddy current in the core and conductors held in magnetic field.
How do you separate hysteresis and eddy current losses?
The eddy current loss occurs because of the interaction of magnetic field and conductor. The hysteresis loss occurs because of the reversal of the magnetism. The eddy current loss is minimised by using the thin core of lamination. The silicon steel material is used for minimising the hysteresis loss.
What is eddy current loss in a circuit?
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.
What is the use of eddy current in induction heating?
However, there are some uses of this eddy current like in Induction heating. In the case of induction heating, an iron shaft is placed as a core of an induction coil. The effect of eddy current is also used in electrical instruments like in induction type energy meters for providing braking torque
What are the effects of eddy currents on conductors?
Eddy currents can also have undesirable effects, for instance power loss in transformers. In this application, they are minimized with thin plates, by lamination of conductors or other details of conductor shape. Self-induced eddy currents are responsible for the skin effect in conductors.
What is the formula for eddy current losses in transformer?
The eddy current losses are proportional to the square of the form factor a = V R M S V A V so that: a = form factor of the actual voltage. Hysteresis and eddy current losses form the iron losses. They are sometimes called the constant losses of the transformer since they do not depend upon the load but only the magnetic induction.