The electromagnetic sensor takes advantage of the relationship between electricity and magnetism, i. E. The current through a single conductor creates a magnetic field around it. The magnetic field would be greatly enhanced if the conductor were to be orbited around a wire, forming a static magnetic field with a shape similar to that of a bar-shaped magnet with a visible arctic and antarctic。
A hollow electromagnetic circle
Empty loop
The magnetic fluxes generated around the coil are proportional to the flow of electricity in the circle, as shown in the figure. The static magnetic field will increase in intensity if additional guidance layers are rounded on the same wire and the same current passes through them。
Therefore, the strength of the magnetic field in the coil is determined by the number of amperidians in the coil. The greater the number of conductors in the circle, the greater the static magnetic field around it。
But if we reverse the idea, cut the current of the wire and place a bar of magnets in the core of the online circle, not the heart of the hollow. By “in” and “out” the bar of magnets, the physical motion of magnetic fluxes is felt in the online circle。
Likewise, if we keep a strip of magnets still and move them back and forth in the magnetic field, the current is felt in the loop. Then, by moving the conduit or changing the magnetic field, we can sense voltage and currents in the online circle, a process called electromagnetic induction, which is the fundamental working principle of transformers, electric motors and generators. The electromagnetic sensor was first discovered by michael faraday in the 1930s. Faraday noted that when he moves the permagnetic into and out of the coil or a single coil, he senses electric motion (emf), in other words, the generation of voltage and the generation of currents。
As a result, michael faraday discovered a method of generating currents in circuits only through the force of the magnetic field rather than using batteries. This led to a very important law that linked electricity to magnetism, the law of electromagnetic sensation of faraday. So how does this work
When the magnet below moves towards the circle, the guidance or needle of the calibrationometer (which is essentially a very sensitive central zero-point flow table) will deviate from its central position in only one direction. When the magnet stops moving and remains static relative to the coil, the guidance of the currentometer returns to zero because the magnetic field does not have physical motion。
Similarly, when magnets move " away" from the circle in another direction, the direction of the calibration pointer is reversed in the opposite direction relative to the polarity of the first indication. Then, by moving the magnet back and forth to the circle, the pointer of the calibration will turn, positive or negative, to the left or to the right in the direction of the magnet's movement。
Electromagnetic induction by moving magnets
Electromagnetic induction
Similarly, if the magnet is now static and only the circle moves towards the magnet or away from the magnet, the calibration pointer will shift in either direction. The motion of the magnetic field moving wire or conductor ring is then felt in the online circle, which is proportional to the speed or rate of movement。
And then we can see that the faster the magnetic field moves, the greater the electric motion or voltage felt in the coil, so that the faraday law is in place, there must be a “relative motion” or movement between the coil and the magnetic field, and the magnetic field, the coil or both can move。
Faraday sensory law
From the above description, we can say that there is a relationship between voltage and the changing magnetic field, and michael farah's famous law of electromagnetic sensing states: “when there is a relative movement between the conductor and the magnetic field, the voltage is felt in the circuit and the size of the voltage is proportional to the rate of change in the magnetic flux”。
In other words, electromagnetic sense should be the process of generating voltage using the magnetic field to generate currents in closed circuits。
So how much voltage can be felt in the online circle by using magnetic force alone? Three different factors determine this。
1) increase the number of conductors in the coil - by increasing the number of individual conductors that cut the magnetic field, the sensor electric motion will be the sum of all individual rings in the coil, so that if there are 20 radiums in the coil, the sensor electric motion will be 20 times greater than the single conductor。
2) increase the relative motion speed between the coil and the magnet - if the same coil passes through the same magnetic field, but the speed or rate increases, the conductor will cut the magnetic line at a faster rate, thus generating more sensory electric motion。
3) increase the strength of the magnetic field - if the same coil moves through the stronger magnetic field at the same speed, more electric motion will be generated by more magnetic line cutting。
If we can move the magnets shown in the above chart into and out of the wires without stopping at constant speed and distance, we will produce a continuous sensory voltage that will alternate between positive and negative polarity, generating communication or an ac output voltage, which is the rationale for generator workings, similar to that used for generator and vehicle exchange generators。
In small generators (e. G. Bicycle generators), a small permagnetic is rotated within the fixed circle by the function of a bicycle wheel. Alternatively, electro-magnetics powered by fixed current voltage can be rotated within a fixed circle, for example, in large generators, both of which generate communication electricity。
Simple generators using magnetic sensors
Electromagnetic sensors
The simple generator above consists of a permagnetic body that rotates around the central axis and is placed next to the rotating magnetic field. When the magnet rotates, the magnetic field around the top and bottom of the circle changes continuously between the arctic and the antarctic. This rotational movement of the magnetic field leads to the sensing of the exchange of electric motion in the online circle, as defined by faraday electromagnetic response law。
The size of the electromagnetic induction is proportional to the magnetic flux density beta, the number of rings gives the total length of the conductorl (in millimetres) and the rate or rate of change of the magnetic field in the conductive body (in m/s or m/s), given by a live electric motion expression:
Faraday live dynamic expression
Faraday senses electric power
If the conductor does not move through the magnetic field by a straight angle (90°), the angle gill will be added to the above expression, and the output will decrease as the angle increases:
The law of electro-dynamic voltage in non-direct angles
Faraday's law tells us that by moving the conductor in the magnetic field or moving the magnetic field over the conductor, the voltage can be felt in the conductor and the current will flow if the conductor is part of the closed circuit. The voltage is referred to as the induction of electric motion, because it is detected by a changing magnetic field through electromagnetic sensing in the conductor, and the negative number in the farah law tells us the direction of the induction of the current (or the polarity of the induction of electric motion)。
But the magnetic fluxes of change can produce a variable current in the online loop, which itself, as we see in the electromagnetic tutorial, produces its own magnetic field. The faster the current changes, the greater the power of the opposition. This self-impressive dynamic is opposed to current changes in the coil in accordance with the law of twilight, and, because of its direction, it is commonly referred to as anti-electric。
The secondary law states that “the direction of the sensory motor is always against the change that causes it”. In other words, sensory currents are always opposed to the movement or change that initially triggered the sensory current, an idea found in the electron analysis。
Similarly, if the magnetic flux is reduced, the induction electric motion will be countered by creating and absorbing the magnetic flux, which is added to the original magnetic flux。
It is one of the basic laws of electromagnetic sensing that determines the direction of the sensory current flow and is related to the constant law of energy。
According to the law of energy continuity, the total energy in the universe will remain constant, as it cannot be created or destroyed. The law of the second degree was derived from michael faraday's sense law。
A comment on the last point of the law in electromagnetic sensing. We now know that when there is a relative movement between the conductor and the magnetic field, the conductor senses electric motion。
However, the conductor may not actually be part of the circuit circuit, but may be the steel core of the ring or other metal parts of the system, such as transformers. Sensitivity dynamics within the metal component of the system can cause circulation around it, a type of core current called vortex。
The vortex core of the vortex generated by electromagnetic sensing or any connected metal parts in the magnetic field are circular, as for magnetic fluxes, they are like a single-ring lead. The vortex does not contribute to the usefulness of the system, but rather produces electrical resistance to heating and power loss at the core by opposing the movement of sensor currents as negative. However, in some electromagnetic induction furnace applications, only vortex is used to heat and melt iron and magnetic metals
Turbo cycle in transformer
Turbo
Changes in magnetic fluxes in the iron core of the transformer above will be felt not only in primary and secondary circuits but also in the steel core. The steel core is a good conductor, so the sensory current in the solid steel core is large. In addition, the direction of vortex flows reduces the magnetic fluxes generated by the primary coil in accordance with the law of twilight. As a result, increased currents required for a given b field are generated in the primary coil, and the magnetic detour curve becomes wide along the h axis。
Iron core layer
Iron core layer
Turbs and magnetic deflation cannot be completely eliminated, but can be significantly reduced. Magnetic core material for transformers or wires is not solid iron cores, but is a "layered" magnetic route。
These layers are very thin insulations (usually varnished) of metals, connected together to form the solid core. The layer increases the electrical resistance of the steel core, thereby increasing the total electrical resistance to vortex flow, thus reducing the loss of the sensor vortex power in the core, which is why both transformers and the electrical magnetic circuits are layers。
