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Toroidal Transformers

A reliable source for Toroidal Transformers information and leading Toroidal Transformers Companies & Manufacturers.

A toroidal transformer is an electrical transformer with a torus or donut-shaped core. The torus core’s surface is covered by its primary and secondary windings, spaced apart by an insulating substance. Any magnetic flux leakage is minimized in this design. Toroidal transformers provide several advantages over conventional square and rectangular-shaped transformers, making them appropriate for delicate and important electronic circuits. Read More…

Toroidal Transformers A toroidal transformer is an electro-magnetic device used to transfer electrical energy away from one electric circuit and toward another without changing its frequency. Toroidal transformers are donut-shaped transformers, which are highly space efficient and excellent for reducing electromagnetic interference. Offering quiet, efficient operation, toroidal transformers have very low stray magnetic fields because they have almost no air gaps.
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Leading Manufacturers

Antigo, WI  |  800-826-9741

We believe in offering the very best to all customers. We offer a full range of transformers, including electric transformers, current, and toroidal transformers.

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Johnson Electric Coil Company $$$

Perris, CA  |  951-277-0757

With more than 500 current transformer manufacturers in the world, Triad Magnetics realizes you have a choice. Why choose Triad? Having served the needs of many industries for more than half a century, Triad believes its experience makes the difference. And if there is one point experience has taught it, it is that it must remain flexible and adaptable to the changing needs of the market.

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Triad Magnetics $$$

McHenry, IL  |  815-344-2900

Lenco Electronics, Inc. specializes in a wide variety of custom electric transformers. Lenco’s success has not come about by accident, but by providing its customers with high-quality products.

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Lenco Electronics, Inc. $$$

Buffalo, NY  |  716-896-6500

With over 95 years of service in the power industry, Niagara Power Transformer Corporation has the experience to be one of the best in the field. Our focus is on producing top-quality products, being fast, reliable, and driven. We manufacture a large variety of transformers, including single-phase, substation, on-load tap changing, step-up, and more! We are focused on continually improving our products and our service, so you are only ever getting the best from us.

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Niagara Power Transformer Corp. $$$

St. Louis, MO  |  636-343-8518

CR Magnetics offers a complete line of products to monitor any group or individual power-using equipment. From multi-function digital communication transducers to simple current transformers, our products enable the designer to choose the exact component that provides the maximum benefit to the system.

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CR Magnetics, Inc. $$$
placeholder image Johnson Electric Coil Company Triad Magnetics Lenco Electronics, Inc. Niagara Power Transformer Corp. CR Magnetics, Inc.

custom torodial transformers

Compared to conventional shell and core-type transformers, toroidal transformers offer greater design freedom, efficiency, and compactness. They are the perfect solution for low-KVA of up to 15 KVA-rated devices and machinery used in industrial, medical, audio applications, and renewable energy.

Toroidal Transformer Operating Principle

A passive electrical transformer uses a magnetic field to create an electromotive force to move electricity from one circuit to another. The circuits are electrically segregated from one another while this is being done. Transformers are used to change the voltage without altering the frequency of the current flow as it steps up or down the voltage. Faraday's law of induction is the basis for how electrical transformers function.

This physical equation describes the connection between the induced electromotive force and the rate at which a magnetic flux changes. A magnetic flux is produced when magnetic field lines go through a conductor. It was discovered that placing a conductor close to a magnetic field with variable amplitude causes that conductor to produce an electric current.

electromagnetic induction principle

Solenoids and toroids are the two types of transformer core forms. In order to be considered a solenoid, the conductor must be long and thin and coil up into numerous, close-knit loops. A perfect toroid would completely contain the magnetic flux, similar to a perfect solenoid. In contrast to the absence of magnetic flux density outside the coil, it is concentrated inside.

toroid core

A toroid core's optimal design is significantly more attainable than a solenoid's. Since it is set up as a loop, it does not have to be indefinitely long. The only prerequisite for a flawless design is to wind the toroid as a whole with windings that are uniformly and tightly coiled. This is probably why Faraday employed a toroidal core rather than a solenoid when he discovered induction. A toroid's circular design makes it simple for the magnetic flux to form a loop without needing an additional return path.

Advantages of Toroidal Transformers

High Efficiency

With typically between 95 and 99% efficiency, toroidal transformers are more efficient than other transformers. This is due to the design's near-optimal construction, which perfectly seals the magnetic flux within the windings. As a result, there is no flux leakage. The magnetic flux is effectively used to couple the main and secondary windings because it is concentrated inside the coil windings, and the windings are uniformly distributed throughout the toroid core.

Electromagnetic Shielding

Toroidal cores naturally insulate nearby components against electromagnetic interference due to the efficient magnetic flux (EMI) containment. They are ideal for electronic devices with delicate components because of this property.

Lower Off-load Losses

Off-load losses occur when the transformer's core is magnetized even though no load is attached to the secondary circuit. As a result, transformers frequently use energy even when they are on standby. Due to their efficient construction, core losses in toroidal transformers are smaller than in regular solenoid-core transformers. Toroidal has fewer off-load losses as a result.

No Air Gap

In contrast to solenoid cores, which have a continuous structure with a significant air gap, toroidal cores are built differently. Air gaps contribute to various detrimental impacts, including noise and the propagation of magnetic flux, or fringing. Three air gaps are present in a typical solenoid core, such as an EI core. Magnetic flux leaks travel via nearby exterior parts at these sites.

transformer air gap

Lower Heat Generation

Transformer electrical energy losses eventually result in vibrations and heat. Hysteresis, copper resistance, and eddy currents are the main sources of heat generation. Due to their great efficiency, toroidal transformers produce less heat and can operate without coolant or heat sinks.

Disadvantages of Toroidal Transformers

Expensive Construction

Toroidal transformers are more expensive to produce than other types of transformers, having lower profiles and requiring fewer materials.

Higher Inrush Currents

When the transformer is switched on, there is a surge in the current known as inrush current. This is caused by the primary circuit using a lot of initial currents when the secondary circuit is coupled to a load. In highly efficient transformers like toroid transformers, the amount of inrush current is larger.

Suitable For Single Phase Application

The use of toroidal transformers is restricted to single-phase systems. Three-phase toroidal transformers are marketed but are less common than the more traditional core and shell-type transformers. Only specific applications require the usage of three-phase toroidal transformers.

Application of Toroidal Transformers

  • Power supply systems
  • Power inverters
  • Audio systems
  • Control equipment
  • Other electronic devices

Choosing the Correct Toroidal Transformer Supplier

For the most productive outcome when purchasing toroidal transformers from a toroidal transformer supplier, it is important to compare several suppliers using our directory of toroidal transformer companies. Each toroidal transformer supplier has a business profile page highlighting their areas of experience and capabilities, and a contact form to directly communicate with the supplier for more information or request a quote. Review each toroidal transformer business website using our patented website previewer to get an idea of what each company specializes in. Then, use our simple RFQ form to contact multiple toroidal transformer businesses with the same form.

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