Some people may still be confused about how the rules for the SMPS transformer or commonly called ferrite transformers.

Previously there were several rules for selecting wire diameters based on the frequencies used. After knowing the wire that is used based on the frequency of the MOSFET driver that is used now we see first the formula determines the primary winding Np.

For example, the above formula is specifically for push-pull topology. Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits. If you have a personalized circuit requirement you may feel free to request it through the comment box or contact me. Wow, the article is really good. Emoticon Emoticon. Electronic Circuit. Sunday, June 23, Publisher Elcircuit.

For example, I want to make an inverter transformer with specifications:. Now we calculate Primary Turn Ns. To optimize the voltage-current, you can double the number of wires in accordance with the power and capacity of the bobbin. Related Circuit. Power Supply Circuit. Elcircuit Electronic Circuit is a good site for hobbyist also who would like to try DIY because it shared good circuits.

Next Post. Previous Post. Unknown Sunday, July 14, X-Factor Wednesday, July 24, Subscribe to: Post Comments Atom.When the primary winding of a transformer is energized with an alternating current ACalternating magnetic lines of force, called "flux," circulates through the core, establishing a magnetic field.

Photo: Quora. Transformers efficiently transfer electrical energy from one circuit to another by means of magnetic induction.

Each phase of a transformer is composed of two separate coil windings wound on a common core. The transformer primary winding receives electrical energy from the power source. When the primary winding is energized with an alternating current ACalternating magnetic lines of force, called "flux," circulates through the core, establishing a magnetic field.

With a second winding wrapped around the same corea voltage is induced by the magnetic field. This winding is called the secondary winding. The amount of voltage induced in each turn of the secondary winding will be the same as the voltage across each turn of the primary winding; this is referred to as the transformer turns ratio. If the secondary winding has fewer turns than the primary, a lower voltage will be induced in the secondary.

This type of transformer is called a step-down transformer. A secondary coil with twice as many turns as the primary will be cut twice as many times by the magnetic fluxand twice the applied primary voltage will be induced in the secondary. This transformer is known as a step-up transformer.

Note: The primary is always connected to the source of powerand the secondary is always connected to the load. Either the high- or low-voltage winding can be the primary or the secondary. The total induced voltage in each winding is proportional to the number of turns in that winding and the current is inversely proportional to both voltage and number of turns.

E1 is the primary voltage and I1 the primary current, E2 the secondary voltage and I2 the secondary current, N1 the primary turns and N2 the secondary turns. If voltage is stepped up, the current must be stepped down and vice versa. The number of turns remains constant unless there is a tap changer.

If the primary voltage of a transformer is volts Vthe primary winding has turns, and the secondary winding has turns, what will the secondary voltage be?

Since there is a ratio of 1 to 4 between the turns in the primary and secondary circuits, there must be a ratio of 1 to 4 between the primary and secondary voltage and a ratio of 4 to 1 between the primary and secondary current.

As voltage is stepped up, the current is stepped down, keeping volts multiplied by amps constant. This is referred to as " volt amps. Calculate the ratio of each three-phase winding based on the line to neutral voltage of the wye winding. Divide the line-to-line winding voltage by 1.

Check the tap changer position to make sure it is set where the nameplate voltage is based. Otherwise, the turns ratio test information cannot be compared with the nameplate.

The turns ratio test is capable of detecting shorted turns in the windingwhich indicate insulation failure by determining if the correct turns ratio exists. Shorted turns may result from short circuits or dielectric failures. Measurements are taken by applying a known low voltage across one winding and measuring the induced-voltage on the corresponding winding. The low voltage is normally applied across a high-voltage winding so that the induced-voltage is lower, reducing hazards while performing the test.

Look at the nameplate phasor diagram to find out what winding on the primary corresponds to a winding on the secondary. The voltage ratio obtained by the test is compared to the nameplate voltage ratio. The ratio obtained from the field test should fall within 0. New transformers of good quality normally compare to the nameplate within 0. The test is performed and calculated across corresponding single windings.

How often does partial discharge occur?For Quick review and summary of Calculations, see the tables at the end of this article. Make sure you have knowledge of Basics of Transfomer. We are going to design a 50 VA step down transformer of V to 12V. Necessary calculations along with formulae are given below in details:.

So, Turns per volts are 2. As, for copper the current density is taken as 2. Selection of wire can also be done by calculating primary current and by cross match the standard table of copper wire according to their current handling capabilities. From the standard copper wire, table it can be seen that wire of this thickness is of 15 gauge. So for secondary winding we need 15 gauge wire. At this point you have done the Calculations and you have the characteristics of transformer components.

Now, for making in hard form, see few easiest steps of hardware implementation of calculations :. I was looking for formulas to calculate transformar for example i have transformar but i want to rewind it with different input and output ac. Core Calculations. Then he computes the unknown one. I learned to do that when I was 3rd grade in school. Where do you come from? Ai is taken according to the standard bobin sizes available in market.

Hello sir, can i apply this on SWG magnetic wire? We dont use here in philippines AWG table. You can calculate the current in each winding and according to maximum current, you can choose wire from wire gauge table of your ease.

If i sent you a nameplate from a transformer do you think you could estimate the copper content of the transformer with much accuracy? I can give it try. Anyone knows why the efficiency effect is only applied on primary current?? How about the secondary current? Why is also the perimeter value is using 1. As we are not taking other parameters into account for winding. Thank you for your design of this single phase transformer, all your explanations are very clear and straight to the point.

It will be very nice if you could please let us have also a design for a three phase transformer.Calculate the voltage output by the secondary winding of a transformer if the primary voltage is 35 volts, the secondary winding has turns, and the primary winding has turns. Transformer winding calculations are simply an exercise in mathematical ratios.

If your students are not strong in their ratio skills, this question provides an application to sharpen them! Most transformer problems are nothing more than ratios, but some students find ratios difficult to handle.

Questions such as this are great for having students come up to the board in the front of the classroom and demonstrating how they obtained the results. Calculate the number of turns needed in the secondary winding of a transformer to transform a primary voltage of volts down to a secondary voltage of volts, if the primary winding has turns of wire.

Predict how all component voltages and currents in this circuit will be affected as a result of the following faults. Consider each fault independently i. The purpose of this question is to approach the domain of circuit troubleshooting from a perspective of knowing what the fault is, rather than only knowing what the symptoms are.

Although this is not necessarily a realistic perspective, it helps students build the foundational knowledge necessary to diagnose a faulted circuit from empirical data. Questions such as this should be followed eventually by other questions asking students to identify likely faults based on measurements.

Suppose turns of copper wire are wrapped around one portion of an iron hoop, and turns of wire are wrapped around another portion of that same hoop. If the turn coil is energized with 15 volts AC RMShow much voltage will appear between the ends of the turn coil? Calculate the voltage output by the secondary winding of a transformer if the primary voltage is volts, the secondary winding has turns, and the primary winding has turns.

If a coil of insulated wire is wrapped around an iron core, an inductance will be formed. Even if the wire has negligible resistance, the current through the coil from an AC source will be limited by the inductive reactance X L of the coil, as the magnetic flux in the iron core oscillates back and forth to induce a counter-EMF:. Your students ought to know what it is, and that it should be applied to this question!

If we wrap a second coil of wire around the same magnetic core as the first inductor coil, we set up a situation where mutual inductance exists: a change of current through one coil induces a voltage in the other, and visa-versa.

This, obviously, will result in an AC voltage being induced in the second wire coil:. What name is given to such a device, with two coils of wire sharing a common magnetic flux? Also, plot both the magnetic flux waveform and the secondary induced voltage waveform on the same graph as the primary applied voltage waveform:. Note: the relative amplitudes of v p and v s are arbitrary. I drew them at different amplitudes for the benefit of the reader: so the two waveforms would not perfectly overlap and become indistinguishable from one another.

Ask your students how the secondary coil would have to be made in order to truly generate a voltage greater than the applied primary coil voltage. How about generating a secondary voltage less than the primary? Identify the polarity of voltage across the load resistor at this exact moment in time, as well as the direction of current in each of the windings.

Follow-up question: note the relationship between direction of current and polarity of voltage for each of the transformer windings. One perspective that may help students understand the directions of current through each winding of the transformer, in relation to the voltage polarities, is to think of each winding as either being a source of electrical power or a load.

Imagine these sources and loads are DC so we may maintain the same polarity of voltage, for the sake of analysis. Which way would you draw the currents for a DC source and for a DC load? The ignition coil of a gasoline-powered internal combustion automobile engine is an example of a transformer, although it is not powered by alternating current.

Explain how a transformer may be operated on electricity that is not AC:. In order for a transformer to function, the primary winding current must change rapidly with regard to time. Whether this is a current that truly alternates, or just one that pulses in the same direction, is irrelevant.

Challenge question: is the wave-shape of the secondary voltage sinusoidal? Why or why not? This question also addresses an issue sometimes misunderstood by students, that transformers are fundamentally AC devices, not DC. It might be a good idea to have an automotive ignition coil available for for classroom demonstration. In lieu of a spark plug, a neon lamp may be used to indicate the presence of high voltage.Calculating ferrite transformer is a process in which engineers evaluate the various winding specifications, and core dimension of the transformer, using ferrite as the core material.

This helps them to create a perfectly optimized transformer for a given application. The post presents a detailed explanation regarding how to calculate and design customized ferrite core transformers. The content is easy to understand, and can be very handy for engineers engaged in the field of power electronicsand manufacturing SMPS inverters.

You might have often wondered the reason behind using ferrite cores in all modern switch mode power supplies or SMPS converters. Right, it is to achieve higher efficiency and compactness compared to iron core power supplies, but it would be interesting to know how ferrite cores allow us to achieve this high degree of efficiency and compactness?

It is because in iron core transformers, the iron material has much inferior magnetic permeability than ferrite material.

### Transformer Calculator

In contrast, ferrite cores possess very high magnetic permeability. Meaning, when subjected to a magnetic field, ferrite material is able to achieve a very high degree of magnetization, better than all other forms of magnetic material. A higher magnetic permeability means, lower amount of eddy current and lower switching losses. A magnetic material normally has a tendency to generate eddy current in response to a rising magnetic frequency.

As the frequency is increased, eddy current also increases causing heating of the material and increase in coil impedance, which leads to further switching losses. Ferrite cores, due to to their high magnetic permeability are able to work more efficiently with higher frequencies, due to lower eddy currents and lower switching losses.

Now you may think, why not use lower frequency as that would conversely help to reduce eddy currents? It appears valid, however, lower frequency would also mean increasing the number of turns for the same transformer. Since higher frequencies allow proportionately lower number of turns, results in transformer being smaller, lighter and cheaper.

This is why SMPS uses a high frequency. In switch mode inverters, normally two types of topology exits: push-pull, and Full bridge. The push pull employs a center tap for the primary winding, while the full bridge consists a single winding for both primary and secondary. Actually, both the topology are push-pull in nature. In both the forms the winding is applied with a continuously switching reverse-forward alternating current by the MOSFETs, oscillating at the specified high frequency, imitating a push-pull action.

The only fundamental difference between the two is, the primary side of the center tap transformer has 2 times more number of turns than the Full bridge transformer. Calculating a ferrite core transformer is actually quite simple, if you have all the specified parameters in hand.

For simplicity, we'll try to solve the formula through an example set up, let's say for a watt transformer. The power source will be a 12 V battery.When the primary winding of a transformer is energized with an alternating current ACalternating magnetic lines of force, called "flux," circulates through the core, establishing a magnetic field. Photo: Quora. Transformers efficiently transfer electrical energy from one circuit to another by means of magnetic induction. Each phase of a transformer is composed of two separate coil windings wound on a common core.

The transformer primary winding receives electrical energy from the power source. When the primary winding is energized with an alternating current ACalternating magnetic lines of force, called "flux," circulates through the core, establishing a magnetic field. With a second winding wrapped around the same corea voltage is induced by the magnetic field.

This winding is called the secondary winding. The amount of voltage induced in each turn of the secondary winding will be the same as the voltage across each turn of the primary winding; this is referred to as the transformer turns ratio. If the secondary winding has fewer turns than the primary, a lower voltage will be induced in the secondary. This type of transformer is called a step-down transformer.

A secondary coil with twice as many turns as the primary will be cut twice as many times by the magnetic fluxand twice the applied primary voltage will be induced in the secondary. This transformer is known as a step-up transformer. Note: The primary is always connected to the source of powerand the secondary is always connected to the load. Either the high- or low-voltage winding can be the primary or the secondary.

The total induced voltage in each winding is proportional to the number of turns in that winding and the current is inversely proportional to both voltage and number of turns. E1 is the primary voltage and I1 the primary current, E2 the secondary voltage and I2 the secondary current, N1 the primary turns and N2 the secondary turns.

If voltage is stepped up, the current must be stepped down and vice versa. The number of turns remains constant unless there is a tap changer.

If the primary voltage of a transformer is volts Vthe primary winding has turns, and the secondary winding has turns, what will the secondary voltage be? Since there is a ratio of 1 to 4 between the turns in the primary and secondary circuits, there must be a ratio of 1 to 4 between the primary and secondary voltage and a ratio of 4 to 1 between the primary and secondary current.

As voltage is stepped up, the current is stepped down, keeping volts multiplied by amps constant. This is referred to as " volt amps.

Calculate the ratio of each three-phase winding based on the line to neutral voltage of the wye winding. Divide the line-to-line winding voltage by 1. Check the tap changer position to make sure it is set where the nameplate voltage is based. Otherwise, the turns ratio test information cannot be compared with the nameplate. The turns ratio test is capable of detecting shorted turns in the windingwhich indicate insulation failure by determining if the correct turns ratio exists.

Shorted turns may result from short circuits or dielectric failures. Measurements are taken by applying a known low voltage across one winding and measuring the induced-voltage on the corresponding winding.

The low voltage is normally applied across a high-voltage winding so that the induced-voltage is lower, reducing hazards while performing the test. Look at the nameplate phasor diagram to find out what winding on the primary corresponds to a winding on the secondary. The voltage ratio obtained by the test is compared to the nameplate voltage ratio.

**toroidal transformer design formula, coil winding calculator**

The ratio obtained from the field test should fall within 0. New transformers of good quality normally compare to the nameplate within 0. The test is performed and calculated across corresponding single windings.

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Power Factor Improvement using Capacitor Bank. Capacitive reactance formula derivation and calculation. Which bulb will glow brighter in series wiring? Simple touch switch circuit using transistor,IC. Infrared burglar alarm using IC circuit diagram. Different Types of Rectifiers. Order Number. Calculate N1 V1 N2 V2.

N1, Number of turns of Primary Windings. V1, Primary Voltage. N2, Number of turns of Secondary Windings. V2, Secondary Voltage. Frequency In Hz.

## How to Calculate the Winding of a Transformer

Number of Turns. Maximum flux in the core In wb weber. To calculate full load current of a Single Phase Transformer. To calculate full load current of a Three Phase Transformer. Rating of a Single Phase Transformer. Voltage In Volts. Current In Amperes. Rating of a Three Phase Transformer. Web Site.

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