What is Transformer? Types, Where is it used?

We have compiled the tranformators that we use almost every moment of our lives for you;

What is a Transformer?

Transformers transfer energy from one circuit to another by electromagnetic induction. That is, instruments that serve to reduce or increase any alternating current (AC) and voltage level to the desired rate without changing the frequency are called transformers. The abbreviated version of the transformer is the transformer. Transformers are often used for energy transmission and distribution. During the transmission of electrical energy from power plants to areas of use, there is a loss of power and voltage in the form of heat in the lines. In order to minimize this situation, the power must be kept constant and the voltage raised. That's a downgrade. Thus, the sections of conductors used in the lines are reduced, losses are reduced and transmission costs are reduced due to the conductive cost.

Transformer

In general, transformers are used to lower or amplify voltage or current in an electrical circuit. In electronics, it is mainly used to combine amplifiers in different circuits, to convert direct current waves to alternating currents of a higher value and only to transmit certain frequencies. It is used for insulation purposes and sometimes in addition to capacitors and resistors. In electric current transmission, it is mainly used to increase or decrease the voltage. Special transformers are used in measuring instruments.

Transformer History

Michael Faraday discovered the basic principle of operation of the transformer in 1831. Faraday wrapped two insulating wires around an iron ring. He connected the ends of one of the windings to a powerful battery and the other's ends to a galvanometer used to detect electric current. Whenever Faraday activated or disabled the battery, he found that the gauge of the galvanometer was playing slightly, that is, an instantaneous current passed through the second winding; He said he got up from here and induced a momentary current in the second of his first bandage. In addition, the current in the second winding is induced only if the current in the first winding changes; it revealed that if this current flows continuously without changing, no current occurs in the second winding. This phenomenon, which Faraday has determined, is the main principle on which all transformers are based.

One of the first transformers.
One of the first transformers.

What are the types of transformers?

Transformer types are divided into varieties according to their intended use, nucleus type, working environment, number of phases.

By Nucleus Type

According to nucleus type, transformers are divided into three: core type, mantel type and distributed type.

Kernel Type Nucleus

Core-type nuclei are used in transformers with extremely strong and high voltage due to the fact that the windings are easier to insulate. The nucleus type nucleus is one-eyed, and the cross-section of the magnetic nucleus is the same everywhere. The placement of sheet metal parts that form the magnetic nucleus in transformers is very important, it should be noted that their annexes do not overlap. In the images below, you can see the core types formed by placing sheet metal parts of different sizes.

Mantel Type Nucleus

In such nuclei, the windings are wrapped around the middle leg, and the cross-section of the foot in the middle is twice the cross-sections of the feet on the side. Unlike nucleus type, it is used in low voltage, and low power transformers.

Distributed Type Nucleus

They have a "+" image. The bandages are wrapped around the middle foot and surrounded by four legs. In such nuclei, empty operating currents are low due to the lowest level of leakage flux.

By Purpose of Use

Auto Transformer

In auto transformers, a single winding is used both as a primary and secondary. With a smaller size, higher yields are obtained.

Insulation Transformers

The purpose of such transformers is not to transform voltage, but to insulate the two circuits from each other.

Degrading Transformers

It is the type of transformer with the most common use. If the voltage of the secondary winding is lower than the voltage in the primary, that is, if the voltage signal at the output is lower than the inlet, such transformers are called lowering transformers. This type of transformer is used in the chargers of our mobile phones and in our rechargeable brooms.

Booster Transformers

If the voltage of the secondary winding is higher than the voltage in the primary, that is, if the voltage signal at the output is higher than the inlet, such transformers are called booster transformers. This type of transformer is used in televisions.

Measuring Transformers

Measuring transformers are used to measure where current and voltage levels are high. In the secondary windings of these transformers, high current and voltage values are reduced to the levels that measuring instruments can measure. In this way, measurements are carried out easily and safely. These transformers are divided into current transformers and voltage transformers.

By Work Environment

Transformers have a wide variety of working environments, as they are used almost everywhere there is electrical energy. There are also many types of transformers in many sizes. Transformers are classified according to working environments based on factors such as cold or hot weather conditions, water and pressure. In mainly mentioned, they are classified as platform type transformers, underground transformers, underwater transformers and indoor transformers.

By Phase Number

Single Phase Transformers

Single-phase transformers have one primary winding. So it has only one entrance. The secondary winding in the transformer can be one or more.

Multi-Phase Transformers

Multi-phase transformers have multiple primary windings, that is, the input signal is two or more. Usually this number of wrapped phases is three. Transformers of this type are classified according to their primary and secondary numbers. (Example: Three-phase transformers, transformers that convert into twelve phases)

Where is the Transformer Used?

In general, transformers are used to lower or amplify voltage or current in an electrical circuit. In electronics, it is mainly used to combine amplifiers in different circuits, to convert direct current waves to alternating currents of a higher value and only to transmit certain frequencies. It is used for insulation purposes and sometimes in conjunction with capacitors and resistors. In electric current transmission, it is mainly used to increase or decrease the voltage. Special transformers with low loss level are used in measuring instruments.

How does the transformer work?

According to Lenz law, in order to indurge voltage in a conductor, the conductor will either be moving within a fixed magnetic field or will remain stationary within a moving magnetic field. Since transformers do not have a moving conductor, the magnetic field must be mobile. For this purpose, an alternative electrical energy applied in primary windings on a transformer with secondary windings on an idle transformer creates a low current. This current on the primary winding also creates a magnetic flux.

The basic principle of operation of the transformer was discovered by Michael Faraday in 1831. Faraday wrapped two insulating wires around an iron ring. He connected the ends of one of the windings to a powerful battery and the other's ends to a galvanometer used to detect electric current. Whenever Faraday activated or disabled the battery, he found that the galvanometer's gauge was playing slightly, meaning a momentary current passed through the second winding. Based on this, he said, the first winding induced an instantaneous current in the second. In addition, the current in the second winding is induced only if the current in the first winding changes; it revealed that if this current flows continuously without changing, no current occurs in the second winding. This phenomenon, which Faraday determines, is the main principle on which all transformers are based. This phenomenon, called electromagnetic induction, can be explained as follows: When the battery is activated, the magnetic field around the first winding also affects the second winding. If there is a wire near this alternating magnetic field, it passes an electric current through the wire. That's why an electric current occurs in the first winding. Just like this, when a coil of the transformer is connected to an alternating current source, rapid directional changes in the current create an ever-changing magnetic field, thereby creating a variable voltage between the ends of the second coil.

Transformer Losses

Since transformers do not have rotating parts, there are no team losses such as friction and wind losses. Therefore, their efficiency is higher than other electrical machines. However, as with all electrical machines, transformers have losses.

Iron Losses

They are losses in the transformer in empty operation. If copper losses caused by the very small current are not taken into account, there are only iron losses in the empty work. Iron losses are also called nucleus or core losses. Iron losses are divided into hysterical and fuco (fukolt) losses.

Hysterical Loss

Some ferromamangtic substances, such as iron, begin to exhibit magneticity temporarily or permanently when exposed to external magnetic field. This magneticity is in the opposite direction to the existing magnetic field on the transformer, causing a loss of energy as heat. This loss is called hysterical loss. Hysterical loss occurs in the form of heat as a result of the molecules rubbing with each other during the change of direction of nucleus molecules depending on the frequency.

Fuko (Fukolt) Loss

When variable current is passed through a coil wrapped around a nucleus, the tension on the nucleus is induced. This voltage causes numerous current paths to form in closed cycles. This event occurs not only on the surface of the nucleus, but also inside. These currents, which form in the form of closed tiny rings, are called fuco currents ( eddy currents). The current intensity in each closed current path is proportional to the voltage directly induced. Current intensity is inversely proportional to the electrical resistance of this current path.

Copper Losses

Copper loss is a term often used for heat generated by electric current in conductors of transformer windings or other electrical appliances. Copper losses in transformers are directly proportional to the resistance of the conductor used in the winding and the square of the current passing through the conductor. Copper loss can be reduced to minimum levels by using thick cross-section and low-resistance conductors in low frequency applications. Copper losses are between 3% and 4% of the transformer's visible power at forces below 1000 kVA.

Ideal Transformer

In order for the emk to be induced in a conductor, it must be moved within a fixed magnetic field and contained within a changing magnetic field. Assuming that the magnetic battery generated by the primary current in the transformer cuts out secondary windings and there are no nucleus losses, this type of transformer is defined as the ideal transformer. In ideal transformers, all magnetic force lines that cut secondary windings also cut their primary windings. In this case, the voltage of the same value is induced in each winding of both windings of the transformer. Since these voltages induced in primary and secondary windings are formed by the same Φ flux, there is no phase difference between them. In other words, the primary and secondary voltages in transformers are in the same phase.

Single Phase Voltage Transformer

In other words, there is no direct electrical connection between two coil windings for a transformer, so it also calls it an Isolation Transformer.In general, the primary winding of a transformer connects to the input voltage source and converts electrical power into a magnetic field.The work of the secondary winding is to convert this alternate magnetic field into the electric power that produces the required output voltage, as shown.

Transformer Structure (single phase)

  • Here:
  • V P – Primary Voltage
  • V S – Secondary Voltage
  • N P – Number of Primary Windings
  • N S – Secondary Winding Count
  • Φ (phi) – Flux Connection

Note that the winding of the two coils is not electrically connected, but only magnetically connected.A single-phase transformer can work to increase or decrease the voltage applied to the primary winding.When used for a transformer its second primary "increase" in the associated winding voltage, is called an amplifier transformer .When used to "reduce" the voltage in the secondary winding relative to the primer, it is called a Drop transformer.

However, there is a third condition in the secondary winding of a transformer in which it produces the same voltage as the one applied to its primary winding.In other words, its output is the same in terms of voltage, current and transmitted power.This type of transformer is called "Impedance Transformer" and is mainly used for impedance compatibility or insulation of adjacent electrical circuits.

The voltage difference between the primary and secondary windings is obtained by changing the number of coil rotations in the primary winding ( N P ) compared to the number of coil rotations in the secondary winding (N S).

Since the transformer is basically a linear device, there is a ratio between the number of turns of the primary coil and the number of turns of the secondary coil.This rate, called conversion rate, is more commonly known as the "rotation rate" of transformers.This rotation rate value determines the operation of the transformer and the corresponding voltage present in the secondary winding.

It is necessary to know the ratio of the number of wire wraps in the primary winding to secondary winding.The non-unit rotation rate compares the two windings sequencing, and colons, such as 3:1 (3-to-1), are written in a row.This means that in this example, if there are 3 volts in the primary winding, then the secondary winding will be 1 volt, 3 volts to 1 volt.Then, if the ratio between the number of turns varies, we can see that the resulting tensions must change at the same rate, and this is true.

Transformers are all about "proportions".The secondary ratio of the primer, the ratio of input to output and the rotation rate of any transformer will be the same as the voltage ratio.In other words, for a transformer: "rotation rate = voltage ratio".The actual number of wire wraps in any winding usually does not matter, only the rate of winding and this relationship is given as follows:

A Transformers Rotation Rate

Ideally assumed transformer and phase angles: Φ P ≡ Φ S

Note that the order of numbers is very important when expressing the value of a transformer rotation rate, since the rotation rate of 3:1 refers to a very different transformer relationship and output voltage than the rotation rate is given as 1:3.

TransformerQuestion Example 1

A voltage transformer has 1500 round wires in its primary coil and 500 round wires for its secondary coil.What will be the rotation rate (TR) of the transformer.

This ratio of 3:1 (3 to 1) simply means that there are three primary windings for each secondary winding.As the ratio moves from a larger number on the left to a smaller number on the right, the primary voltage value is reduced as shown.

Transformer Question Sample 2

If 240 volt rms are applied to the primary winding of the same transformer above, what happens to the secondary load-free voltage?

Since the primary voltage is 240 volts and the corresponding secondary voltage is lower at 80 volts, it is to reaffirm that the transformer is a "drop" transformer.

Then the main purpose of a transformer is to convert voltages at preset rates, and we can see that its primary winding has an amount or number of windings (wire coils) on it that are set to match the input voltage.If the secondary output voltage will be the same value as the input voltage in the primary winding, the same number of coil windings as in the primary core should be wrapped in the secondary core, giving a double rotation rate of 1: 1.(1 to 1).In other words, a coil is secondary, a coil is opened in the primary coil.

If the output secondary voltage will be greater or higher than the input voltage (amplifier transformer), then there should be more rotations on the secondary that give a rotational ratio of 1:N (1-N), where the number of rotational ratios represents the N.Likewise, if the secondary voltage must be lower or lower than the primary (lowering transformer), the number of secondary windings should be less, giving a rotational ratio of N:1 (N-to-1)..

Transformer Action

Compared to the primary winding, we found that the number of coil rotations in the secondary winding affected the amount of voltage obtained from the secondary coil.But if the two windings are electrically isolated from each other, how is this secondary voltage produced?

We have previously said that a transformer consists mainly of two coils wrapped around a common soft iron core.Alternative voltage (when V P) is applied to the first coil, the name of the current through the coil is a magnetic field around itself, with this current flow according to the joint inducing in the upward rotation sets, electromagnetic induction of faraday law.As the current flow increases from zero to the maximum value given as dΦ/dt, the power of the magnetic field increases.

As the magnetic force lines established by this electromagnet expand outward from the coil, the soft iron core forms a path for magnetic flux and intensifies it.This magnetic flux connects the rotations of both bandages as they increase and decrease in opposite directions under the influence of the AC source.

However, the strength of the magnetic field induced into the soft iron core depends on the amount of current and the number of windings in the winding.When the current is reduced, the magnetic field power decreases.

As magnetic flux lines flow around the nucleus, they pass through the rotations of the secondary winding, causing an induction of a voltage in the secondary coil.The amount of induced voltage will be determined as follows: N*dΦ/dt (Faraday Law), where N is the number of coil rotations.In addition, this induced voltage has the same frequency as the primary winding voltage.

Then, since the same magnetic flux binds the windings of both bandages together, we can see that the same voltage is induced at each coil rotation of both bandages.As a result, the total induced voltage in each winding is directly proportional to the number of windings in that winding.However, if the magnetic losses of the nucleus are high, the peak amplitude of the output voltage present in the secondary winding will decrease.

If we want the primary coil to produce a stronger magnetic field to overcome magnetic losses in the core, we can send a larger current from the coil or allow the same current to flow, and instead increase the number of coil rotations (N P). Wrapping.Multiplication of amperage times turns is called "amperage turns", which determine the magnetization force of the coil.

So, let's say we have a transformer with a single turn in the primary and only one turn in the secondary.If a volt is applied to a rotation of the primary coil, assuming that there is no loss, it is necessary to flow enough current and produce enough magnetic flux to induce a volt in the single rotation of the secondary.That is, each winding supports the same number of volts per turn.

Since magnetic flux varies sinusoidally, the basic relationship between Φ = Φ max sinωt, emk induced in an N-turn coil winding, ( E ) is given as follows:

returns emf = x change rate

  • Here:
  • ε – Flux frequency in Hertz, = ω/2π
  • Ν – the number of coil windings.
  • Φ – the amount of flux in webers

This is known as the Transformer EMF Equation.For primary winding emf, N will be the number of primary turns (N P), and N for secondary winding EMF will be the number of secondary turns (N S).

Also, please note that transformers cannot be used to convert or feed DC voltages or currents, as it requires an alternate magnetic flux for the transformers to function correctly, since the magnetic field must change to inducate a voltage in the secondary winding.In other words, transformers do not operate at stable state DC voltages , they only work at alternating or pulsed voltages.

If the primary winding of a transformer is connected to a DC source, the inductive reactance of the winding will be zero, since the DC has no frequency, so the effective impedance of the winding is very low and will only equal to the resistance of the copper used.Thus, the winding will attract a very high current from the DC source and cause it to overheat and eventually burn, since as we know I = V/R .

Transformer Question Sample 3

A single-phase transformer has 480 turns in its primary winding and 90 turns on the secondary winding.When 2200 volts and 50Hz are applied to the transformer primary winding, the maximum value of magnetic flux density is 1.1T.Calculate:

a).Maximum flux in the core.

B).The cross-sectional area of the core.

C).Secondary induced emk.

Since the secondary voltage rating is equal to the secondary induced emk, an easier way to calculate secondary voltage from the rotation rate is given as follows:

Electric Power in Transformer

Another of the main parameters of the transformer is the degree of power.The power rating of a transformer is achieved by simply multiplying the current by voltage to achieve a degree in Volt-amperage (VA).Small single-phase transformers can only be rated in volt-amps, but much larger power transformers are rated in Kilo volt-amperage (kVA) units and Mega volt units, where 1 kilo of volt-amperage equals 1,000 volts-ampere.  -amperage , ( MVA ) where 1 mega volt-amperage equals 1 million volt-ampere.

In an ideal transformer (ignoring any loss), the current power in the secondary winding will be the same as the power in the primary winding, these are fixed voltage devices, and their power does not change only the voltage-current ratio.Thus, in an ideal transformer, the Power Ratio is equal to one (unit), since the voltage, V times current, I will remain constant.

That is, the electrical power at a voltage/current level on the primary side is "converted" to the same voltage/current level at the same frequency on the secondary side.Although the transformer can increase (or lower) the voltage, it cannot increase the power.Thus, when a transformer raises a voltage, it reduces the current and vice versa, so that the output power is always the same value as the input power.Then we can say that the primary power is equal to the secondary power, ( P P = P S ).

Power in a Transformer

Where: Φ P is the primary phase angle and Φ S is the secondary phase angle.

Since the loss of power is proportional to the square of the transmitted current, that is: I 2 R , to increase the voltage, say doubling the voltage (×2) reduces the current by the same amount, while (÷2) transmits the same amount of power to the load and therefore reduces losses by 4 factors. If the voltage is increased by 10 times, the current decreases by the same factor and reduces total losses by 100 times.

Transformer Foundations – Efficiency

A transformer does not require any moving parts to transfer energy.This means that there is no friction or wind loss associated with other electric machines.However, transformers suffer from other losses called "copper losses" and "iron losses", but these are usually quite small.

Copper losses, also known as I 2 R loss, are electrical power lost in heat as currents circulate around transformer copper windings, hence its name.Copper losses represent the greatest loss in the operation of a transformer.Power loss can be detected by multiplying the actual wattage amperage square and winding (ohm by multiplying it with resistance (as each winding I 2 R).

Iron losses, also known as hysteresis, are the delay of magnetic molecules within the nucleus in response to alternate magnetic flux.This delayed (or out-of-phase) condition is due to the fact that it requires power to reverse magnetic molecules; they don't reverse until the flux reaches enough power to reverse them.

Their reversal results in friction, and friction generates heat in the nucleus, a form of power loss.Hysteresis inside the transformer can be reduced by making core special steel alloys.

The intensity of the power loss in a transformer determines its efficiency.The efficiency of a transformer is reflected in the loss of power (watts) between the primary (input) and secondary (output) windings.Next, the resulting efficiency of a transformer is equal to the power input of the secondary winding, the P S , primary winding, the P P ratio, and therefore high.

An ideal transformer will be 100% efficient by passing all electrical energy received by the primary to the secondary side.However, real transformers are not 100% efficient.When working at full load capacity, their maximum efficiency is close to 94% to 96%, which is still pretty good for an electric device.The efficiency of a transformer running at a constant AC voltage and frequency can be as high as 98%.The efficiency of a transformer is given η as follows:

Transformer Efficiency

Where: Input, Output, and Losses are all expressed in power units.

Usually when dealing with transformers, primary watts are called "volt-amp", VA , to distinguish them from secondary watts .Then the above efficiency equation can be changed as follows:

It is sometimes easier to remember the relationship between the input, output and efficiency of transformers using pictures.Here, three amounts of VA, W and η are placed in a triangle that gives power in watts at the top and volt-amperage and efficiency at the bottom.This arrangement represents the actual position of each quantity in the productivity formulas.

Transformer Efficiency Triangle

and the displacement of the above triangular quantities gives us the following combinations of the same equation:

Then watt (output) = TO find VA x eff. or VA (input) = to find W/eff. or to find efficiency, eff.= W/VA , etc.

Transformer Overview

Then to summarize the training of these transformer foundations.A Transformer uses a magnetic field to change the voltage level (or current level) in the input winding to another value in the output winding.A transformer consists of two electrically isolated coils and operates according to faraday's principle of "mutual induction", in which an EMF is induced in the secondary coil of transformers by magnetic flux produced by voltages and currents flowing in the primary coil winding.

Both primary and secondary coil windings are wrapped around a common soft iron core made of separate laminations to reduce vortex current and power losses.The transformer's primary winding is connected to the AC power supply, which should be sinusoidal in nature, while the secondary winding provides electrical power to the load.However, a transformer can be used in reverse with a secondary winding-dependent feed, provided that voltage and current values are observed.

We can show the transformer in the form of a block diagram as follows:

Basic Display of Transformer

The ratio of the primary and secondary windings of transformers relative to each other produces either an amplifier voltage transformer or a lowering voltage transformer, and the ratio between the primary number of windings and the number of secondary windings is called the "rotation rate". " or "transformer ratio".

If this ratio is more than one, n, <1 o K  G is classified as a larger N, P and transformer as an amplifier transformer.If this ratio is greater than one, n > 1 , that is, if the N P is greater than N S, the transformer is classified as a lowering transformer.Keep in mind that the single-phase reducer transformer can also be used as an amplifier transformer, only by reversing its connections and making the low voltage winding a primary, and vice versa as long as the transformer is operated at the original VA design grade.

If the rotation rate is equal to one, that is, if n = 1, then both the primary and secondary windings have the same number of windings, so the voltages and currents for both primary and secondary windings will be the same.

EXTRA: Strip LED Transformer Account

Strip LED transformer calculations process over current. That is, it is calculated by amperage account. The spent power (W) on a strip LED is calculated by the formula Current(A) x Voltage(V) x Length(m). The strip LED transformer calculation is done in two ways:

LED Transformer

Single Chip Strip LED Transformer Calculation

Single chip strip LEDs are strip LEDs with 3528 chips. The meter has 60 LEDs and draws 0.4 Amps per meter. The operating voltage is 12 Volts. So for example, the only chip strip of 10 meters is 10 x 0.4 = 4 Amps for LED. A single chip strip LED of 10 meters requires a transformer with a current of 4 Amps or higher.

Three Chip Strip LED Transformer Calculation

Three chip strip LEDs are 5050 chip strip LEDs. As with single chip strip LEDs, there are 60 LEDs per meter, but they draw 1.2 Amps of current per meter. The operating voltages are again 12 Volts. 10 x 1.2 = 12 Amps for three chip strip LEDs of 10 meters. A 10-meter three-chip strip LED requires a current transformer of 12 Amps or higher.