Toroidal transformer. How it works and main advantages!

Do you know what the toroidal transformer is and how it works? Toroidal transformers basically have the same working principle as other common transformers, but due to their ring-shaped construction characteristics, their efficiency is much higher. In this article, we will show you all the advantages of the toroidal transformer, come on guys!

Toroidal transformer: What is it?

The word toroidal is referring to the geometric shape of the core, which in the case of this transformer is a round shape similar to a ring. In case you don’t know, the core is the heart of the transformer and it can be manufactured from several magnetic materials, resulting in a huge variation of products.

What are the main advantages of the toroidal transformer?

Toroidal transformer: Main advantages

When comparing the toroidal transformer to ordinary transformers, the toroidal transformer which is made of silicon steel offers several important advantages, such as:

  • Minor irradiation – We can say that the irradiation of the magnetic field around the transformer is very low, preventing the analog or digital electronic circuits that are very sensitive from being affected.
  • Smaller losses – With a very low amount of losses, consumption is also much lower, because the current consumed without load is very small.
  • Minor voltage variation – When we observe the voltage variation in the power output, we can see that it is much smaller in this type of transformer. Therefore, the difference between the unloaded and loaded output voltage is much smaller when compared to that of a conventional transformer.
  • Smaller size – Generally, the toroidal transformer is 40 and 60% smaller and lighter than other conventional transformers.
  • Practicality – Certainly the toroidal transformer offers much greater design flexibility than conventional transformers. When we observe its assembly, the practicality is also greater because this type of transformer can be fixed with just 1 screw or plastic clamps, which considerably reduces the assembly time.
  • Quieter – The mechanical noise of the toroidal transformer is almost imperceptible. During operation, the noise of the core vibration is actually very low.

Toroidal transformer – Features

The size of the common toroidal transformer ranges from 2mm to 15mm. As for frequency, ferrite and iron powder transformers have limited performance for frequencies above 100 kHz. This is because of the rise in temperature and not because of saturation.

It is important to inform that the ferrite cores can present some temperature changes when they are submitted to high intensity of magnetic flux. And in the case of iron powder cores, when they cool down they are able to return to normal permeability values.

This saturation does not generally occur in circuits with power below 500mW, but it should be a factor to be considered in circuits with power above 1W.

As mentioned, the iron cores have lower permeability, so to achieve the same inductance as the ferrite core, more turns are required. This makes it easy to understand why the iron powder cores get more power, this is because the low density will be much lower for a given applied voltage. Therefore, to prevent the flow density from being increased by the smaller number of turns, the applied voltage must be reduced.

Both have advantages and limitations and this must be analyzed before use! The ferrite core toroidal transformer needs fewer turns of the coil windings, except that each wire turn will certainly have a higher impedance. The toroidal transformer with an iron powder core needs more turns of the coil windings, but in this case the impedance is much lower and they can work with greater power.

Toroidal transformer: Core without GAP

One of the main advantages of toroidal transformers is precisely that there is no gap or cuts in their core. GAP’s exist to allow magnetic flux, but in this type of nucleus the losses increase considerably. As the core of the toroidal transformer is homogeneous, that is, without the existence of cuts, its geometric shape makes it much more efficient.

Transformador toroidal: Como usar?

Outra dica importante é determinar qual será o ciclo de trabalho de um transformador, porque isso pode ser fundamental para reduzir o tamanho e também o custo do transformador toroidal que será usado. Para compreender melhor isso, acompanhe este exemplo a seguir!

Um transformador toroidal de 100VA que é utilizado com carga máxima apenas durante pequenos intervalos de tempo, certamente pode ser menor que um transformador toroidal também de 100VA, mas que será utilizado com carga máxima durante muitas horas.  Portando, sempre que for especificar os transformadores que serão usados, é importante mencionar qual será o seu ciclo de trabalho.

Small toroidal transformers are usually more expensive, because the construction process of a toroidal transformer is much more complex than in conventional transformers. This difference is notable only for models below 100VA, that is, when the power of the transformer increases, the price difference between the toroidal and the conventional one decreases.

But it is important to observe much more than the price, since small transformers may be the best option for various applications where a transformer with low weight and / or size is required.

We end here another article and if you have any questions or suggestions, leave them in the comments and we will respond. Here on the website there are several articles talking about transformers and if you want to know more about it, it is worth checking out the other publications.