Toroidal Inductors And Transformers

Inductors are passive electrical components that create a magnetic field to store energy and help protect a circuit from spikes or fluctuations in current. They come in several possible configurations and are used in various applications, including direct energy storage and improving signal transmission and reception in communications equipment.

One common type is the toroidal inductor, which has a distinct closed-loop or donut shape wrapped with insulated copper wire. The shape and wire wrapping pattern increases the magnetic field while also reducing magnetic field loss or leakage. This results in a compact component with higher inductance and lower EMI emissions.

MPS Industries manufactures toroidal inductors and transformers for customers in the automotive, telecommunications, consumer electronics, medical, and other industries. Learn more about the benefits of toroidal inductors, important design and material core considerations, and the types of toroidal transformers we offer.

Benefits of Toroidal Inductors

For certain applications, toroidal inductors offer significant benefits, such as:

Compact design. Donut-shaped inductors are compact and can hold a large amount of windings in this smaller space. As a result, they can fit into smaller assemblies and circuits without sacrificing functionality.
Durability. A toroidal inductor core can be made from durable materials and coatings that add strength and corrosion resistance.
Reduced EMI. Electrical components, including inductors, can introduce EMI that interrupts, blocks, or distorts signals. The closed loop shape of a toroid and closely spaced windings reduce the EMI emitted by the inductor.
Efficiency. The donut shape and coiled wire contain magnetic flux better than straight shapes, and provide greater inductance in a smaller component.
Customizable. The toroid core can be manufactured in a variety of inner and outer diameters, with or without protective coatings, and with different wire wrap configurations. As a result, they can be modified to suit many different electrical applications.

Design Considerations

Toroid inductor design is based on these four primary considerations:

1. Number of Wire Turns

A larger number of windings creates a larger magnetic field and increases the inductance. The toroid shape lends itself to a larger number of windings around the full surface of the ring.

2. Core Material

Iron and ferrite produce a stronger magnetic field than other metals because they are more permeable. The greater the permeability, the bigger the inductance when all other factors are the same. A hollow air core is another option, and this type of core is made from ceramic, plastic, or even just a hollow air-filled space.

3. Core Dimensions

A larger core generally generates higher inductance. Consider inner and outer diameters.

4. Winding Configuration

Single-layer and multi-layer winding configurations produce different inductance capabilities.

5. Air Gap

An air gap will reduce inductance because air is less permeable than the windings.

Types of Toroidal Inductor Cores

The inductor’s core material impacts its inductance and suitability for different applications. Common materials include:

1. Ferrite

These are low-cost cores with good magnetism. They can be made in many shapes and sizes for audio amplification, power supply, and filter applications.

2. Powdered Iron

A powdered iron core has a higher permeability, so it inducts better than a comparable ferrite core. Iron cores are often used for high-power applications like switching power supply assemblies.

3. Amorphous and Nanocrystalline Metals

Amorphous cores are made from metal alloys that are rapidly cooled during fabrication, leading to a disordered structure that is highly permeable with low magnetic loss. Nanocrystalline metals are produced through an annealing process and exhibit even less magnetic loss than amorphous metals.

4. Air Cores

This refers to several types of non-metallic core materials including ceramic, plastic, other non-magnetic material, or even simply a hollow air-filled space inside the coil. They tend to have lower inductance and are used effectively with higher frequency applications.

Toroidal Transformers

Transformers are used to transfer AC power from a primary circuit to a secondary circuit. While inductors have a single wire wound around a core, transformers have two or more. Current flowing through the primary coil creates an electromotive force that generates current in the secondary coil. Transformers can also step voltage up or down to help regulate output.

Our low-frequency (50Hz/60Hz) toroidal power transformers are efficient, quiet, and compact. Most have a standard operating temperature range between 0 °C and 70 °C; however, extended range options are also available.

1. Core Material

We offer these toroidal transformer core options:

Ferrite
Powdered iron
Amorphous
Silicon steel

Choose between single-phase windings for general use or three-phase windings for powerful commercial and industrial applications.

2. Power Rating

We offer low-, medium-, and high-power transformers for consumer goods, commercial systems, and more.

3. Frequency Rating

Toroid transformers can be used with both high and low frequency applications. Depending on the frequency range, different core materials may be required for optimal performance.

Industries Served

MPS Industries provides inductors and transformers for many industries, including:

Automotive
Electronics
Medical
Telecommunications

Quality Toroidal Inductors and Transformers from MPS

MPS builds standard and custom toroidal inductors and transformers to meet the evolving needs of major industries. Our company is ISO 9001:2015 and ISO 14001:2015 certified as part of our commitment to creating quality electrical components and assemblies. We also comply with RoHS, REACH, and conflict mineral standards.