What do eddy currents mean?
When a piece of metal is in a changing magnetic field or moves in a magnetic field, an induced electromotive force will be generated in the metal body, generating thus a current. in the metallic body, which is then called a vortex.
What is a vortex?
The conductor is moving in a magnetic field, or the conductor is stationary but has a magnetic field that changes with time, or both conditions occur at the same time, which can cause a relative cutoff between magnetic field lines. and the conductor. According to the law of electromagnetic induction, an induced electromotive force is generated in the conductor, thereby driving the current. The current distribution in the conductor thus caused varies depending on the shape of the conductor surface and the distribution of the magnetic flux. Its journey often resembles a vortex ofin water, that's why it's called eddy currents.
How it happens. formed eddy currents and what is their role
1. Overview of Eddy Current Testing Eddy current testing (eddy current testing) is one of several non-destructive testing methods ( CND). It applies the basic theory of "electromagnetic" as a basis for testing conductors. The eddy current test consists of bringing a conductor closer to a coil (called a probe) powered by an alternating current. The coil establishes an alternating magnetic field which passes through the conductor and generates electromagnetic induction with it. eddy currents in the conductor. The eddy current in the conductor will also produce its own magnetic field. The magnetic field effect of eddy currents will also change the strength of the original magnetic field, resulting in changes in voltage and impedance.ance of the coil. Therefore, when defects appear on or near the conductor surface or the measured metal material changes, the intensity and distribution of eddy currents will be affected. Changes in eddy currents will cause changes in the voltage and impedance of the sense coil. Based on this change, it can indirectly know the presence of defects in the conductor and if there are any changes in the properties of the metallic material. Due to the different shapes of the test tubes and different detection parts, the shape of the detection coil and the way of approaching the test tube are also different. In order to meet various testing needs, users have designed a variety of test coils and eddy current testing instruments.
What is vortex fever?
Gangs of corrupt officials are the vortexsocial media that people don't need.
What is water vortex?
1. The water vortex refers to the vortex in hydraulics. Generally speaking, this means that the rotational angular velocity vector of the fluid is not zero, also called rotational motion, and the fluid particles or fluid particles rotate around their own axis during motion. Generally, if a vortex is generated, there will be. be another matching vortex. The same principle also applies to vortices, electric vortices, and air pressure (cyclonic) vortices in fluid mechanics.
2. The function of water vortex:
Use the principle of water vortex to make a hydraulic dynamometer.
The principle of eddy currents
The current induced inside a conductor by electromagnetic induction. Also called eddy current. The conductor moves in a magnetic field,or the conductor is stationary but has a magnetic field that changes with time, or both situations occur at the same time, which can cause the magnetic field lines and the conductor to be relatively cut off. According to the law of electromagnetic induction, an induced electromotive force is generated in the conductor, thereby driving the current. This distribution of current in the conductor caused by this method varies depending on the shape of the conductor surface and the distribution of the magnetic field. Its path often resembles a vortex in water, which is why it is called eddy current. Eddy currents generate heat in conductors. The energy consumed comes from the mechanical work of moving the conductor, or from the energy source which creates an electromagnetic field which varies over time. Therefore, in electrical equipment, in order to avoid the generation of eddy currents or reduceenergy loss caused by eddy currents, the cores are stacked with mutually insulated sheets or filaments, and materials with higher resistivity are used, such as silicon steel sheets or cores pressed with iron powder. When a conductor moves through a non-uniform magnetic field or is in a magnetic field that changes with time, the loss of energy due to eddy currents is called eddy current loss. The magnitude of eddy current loss is related to factors such as how the magnetic field changes, the movement of the conductor, the geometry of the conductor, the magnetic permeability, and the electrical conductivity of the conductor. The calculation of eddy current losses should be based on the equation of the electromagnetic field in the conductor, combined with the above factors of the specific problem. A vacuum melting furnace used to melt steelr ally has a coil outside the oven. A repeatedly changing current passes through the coil, creating eddy currents in the metal in the furnace. The heat generated by the eddy currents melts the metal. The advantage of using eddy currents to melt metal is that the entire process can be carried out under vacuum, which prevents air impurities from entering the metal and allows high alloys to be melted. quality. The coils of motors and transformers are wound around the iron core. The changing current flows through the coil, and the eddy currents generated in the iron core cause the iron core to heat up, wasting energy and potentially damaging electrical appliances. So we need to find ways to reduce eddy currents. One solution is to increase the resistivity of the core material. The commonly used core material is acier to silicon. If we look closely at generators, motors and transformers, we can see that their cores are not a single piece of metal, but are made of many thin sheets of silicon steel rolled together. Why is this so? It turns out that when a block of metal is placed in a magnetic field that changes over time or is allowed to move in a magnetic field, an induced current is generated in the block of metal. This type of current forms a closed loop in the metal block, much like the vortex of water, which is why it is called eddy currents or eddy currents. The resistance of the entire metal part is very low, so the eddy currents are often very strong. When a large conductor moves through a magnetic field or is in a changing magnetic field, it generates an induced electromotive force and forms eddy currents, prociting significant losses by eddy currents. To reduce eddy current losses, cores made of thin laminated silicon steel sheets coated with a thin layer of insulating paint or insulating oxide are widely used in AC motors and electrical appliances. In this way, the eddy currents are limited to a narrow sheet. , and the magnetic flux passes through the sheet when the cross section is narrow, the net electromotive force in these loops is small, the loop length is large, the loop resistance is large, and the eddy current is large. weakened. In addition, due to the high resistivity of this thin sheet material (the eddy current loss of silicon steel is only 1/5 to 1/4 of that of ordinary steel), the loss by eddy currents is considerably reduced. On the other hand, eddy currents can be uUsed to make certain induction heating equipment, or damping devices used to reduce oscillation of moving parts. Such as: our common induction cooker. It adopts the principle of eddy current induction heating; the internal part of the electronic circuit generates an alternating magnetic field. When the bottom of a pot containing iron is placed on the surface of the stove, the pot cuts the alternating magnetic field lines and generates. eddy currents in the metal part of the bottom of the pot are formed. The electronic movement in the pot generates thermal energy, which is used to heat and cook the food, thereby achieving the purpose of cooking.
The vortex is the explanation
A vortex is a whirlpool of water formed by the movement of a counter-current. Most whirlwinds are not very strong. A powerful vortex is called a Maelstrom, but it relies on the sameprinciple as a vortex. All vortices with downdrafts can also be called vortices. Ocean eddies are often caused by tides, and very small eddies can be easily seen when a bathtub or sink drains. But these are very different from natural whirlpools. Eddy currents also occur downstream of many waterfalls, a famous example being Niagara Falls.[1] These whirlpools are quite strong, and in narrow, shallow straits, fast-moving water also creates powerful whirlpools.
Eddy currents are sometimes called eddy currents.
I don't know if you are talking about water flow or current?
The structures of electric motors and generators are the same
Electric motors use electricity to generate force, which is electricity to generate magnetism
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Uti generatorsread the force to generate electricity, which is the magnetism to produce electricity
The difference between alternating current and direct current is the collector, which is generally used in motors and DC generators
When the coil rotates a certain angle (such as 90), the function of the switch is to change the direction of the coil current so that the DC can provide power. power continuously and run the motor.
AC will automatically change the direction of the current, so there is no need to have a collector. When the coil rotates by a certain angle (90), due to the coil current, the direction changes and the direction of the generated magnetic field (which can be assumed to be a bar magnet) also changes. , so that the coil continues to be stressed, causing the motor to rotate
In the critical state, it rotates by inertia
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The principle of the generator is the reverse process of the electric motor