Electric Transformers

Electric Transformers

Electric transformers are inductively coupled electromagnetic devices that pass on electrical energy between circuits. What this means is that they regulate voltage (va and kva). Specifically, transformers are capable of patterning, translating, isolating, and increasing and decreasing electrical currents of varying power levels.


Electric transformers have a few different uses. One of the common goals of electric transformers is to ensure that the voltage safely meets the requirements of the equipment. Another is to store and transport in electric power grids and along electric power lines.

Electronic transformation is a necessary process for a wide variety of applications. Examples of equipment and systems that use electric transformers include electrical circuitry, power lines, lights, automobile starters, PCs, solar converters, electric drives, and personal electronics.
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Leading Manufacturers

Perris, CA | 851-277-0757

Babylon, NY | Orange, MA | Willits, CA | | 800-624-8726

Everett, WA | 425-355-1855

McHenry, IL | 815-344-2900

Concord, NH | 800-805-8991

Pelham, NY | 800-431-1064

The History of Electric Transformers

The history of electric transformers starts with the discovery of induction in the 1830s, when both English scientist Michael Faraday and American scientist Joseph Henry were independently studying electromagnets. Via their studies, within a year of one another, without ever speaking, they both discovered the property of induction.

One of the ways that Faraday did this was through an attempt to showcase how electromagnetic fields provide power. To do so, he wrapped two coils around opposite sides of a ring, connecting one to a battery and one to a galvanometer. When connected to the battery, one coil would become powered and then pass this power onto the other coil, proving his theory. What he also learned was that the current would still flow to and power the galvanometer even after disconnected from the battery.

Faraday developed Faraday’s Law in 1831. Faraday’s law states that the induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux enclosed by the circuit. His law helped many scientists and engineers throughout the nineteenth century as they experimented with transformers and power distribution.

In 1836, an Irish reverend working at Maynooth College, Rev. Nicholas Callan, invented the induction coil. His induction coil allowed people to glean high voltages from batteries. Rev. Callan based his invention on his realization that in relation to the primary winding, the more turns the secondary winding experiences, the larger the resulting EMF (e.g. volts per turn: If a primary winding has 1000 turns and secondary winding has 1000 turns, then their turns ratio is 10:1. So, if the primary winding produces 100 volts, the secondary will produce 10.)

In 1886, after buying the patent from John Dixon Gibbs and Lucien Gaulard, the Westinghouse Company began commercially producing transformers with open iron cores. Gibbs and Gaulard called them “secondary generators.” That year, they used the transformers to provide power to an entire town, Great Barrington, Massachusetts.

Meanwhile, in what is now Budapest, Hungary, scientists Ottó Bláthy, Miksa Déri, and Károly Zipernowsky were already moving on from open core transformers, finding them to be unreliable. In 1884, they developed the first high efficiency alternating current (AC) transformer. They used theirs to power alternating current incandescent lighting systems. In 1885, they filed joint patent applications for transformers with two different closed-circuit configurations. Their transformers were 3.4 times more efficient than the ones being manufactured by Westinghouse. From them, we gained two basic transformer constructions that we still use today, core type and shell type.

A few years later, while working for a company in Germany, a Russian engineer named Mikhail Dolivo-Dobrovolsky designed the first three-phase transformer. Independently in the 1880s, a few other inventors also came up with power systems that relied on multiple phases. These inventors include Jonas Wenström, Mikhail Dolivo-Dobrovolsky, John Hopkinson, Galileo Ferraris and Nikola Tesla. Nikola Tesla followed this up in 1891 with the first air-core transformer, called the Tesla coil. The Tesla coil was known for being able to generate exceptionally high voltages at high frequencies.

Since then, these power supplies have evolved to serve applications of all kinds. They are easier to control, more diverse in size, stronger, and more efficient. As time goes on, we can expect this trend to continue.


Manufacturers build electric transformers with a core and windings. Some feature cooling mechanisms and others feature insulation.

Manufacturers may make cores from a number of different materials, including laminated steel (also known as silicon steel, silicon electrical steel, relay steel or transformer steel), powdered iron, or ferrites. Cores may also be empty spaces called “air coils.”

Windings are wires with various strand counts. They are made from conducting wires such as aluminum, copper, enameled magnet wire or grain-oriented silicon steel.

Considerations and Customization
Manufacturers are able to fabricate electric transformers in a wide range of configurations in order to effectively work with all types of electric transformation applications. Transformers can come in various sizes—from a thumb sized transformer in a lamp or a microphone, to a large transformer at a power plant.

When designing your transformer, suppliers think about application specifications like the amount of voltage you require, the size of device or system, the maximum temperature your wires and system can reach, standard requirements, and your budget. Manufacturers base the number of windings they install based on the desired voltage, because the number of windings directly determines the voltage that is transmitted through the magnetic field. The voltage level depends on the ratio of windings in the primary coil to that of the secondary coil. A step down transformer, for instance, will not have as many windings in its secondary than its primary, while a step up transformer will have fewer windings in its primary than its secondary. Also, manufacturers think about the number of primary windings specifically as the number a transformer possesses determines its size and its expense.


Electric transformers are made up of two sets of windings connected by a magnetic field. At the core of a transformer is a compound made up of ferrite or iron, or a laminated core surrounded by copper coils. The two coils are known as primary and secondary coils, both of which serve as conductors.

The primary coil produces a magnetic field around the conductor upon receiving AC voltage. The magnetic field then activates the secondary coil, which changes the voltage and transmits the electricity. Finally, the newly converted electrical energy is moved to the load center, where the rest of the electrical process is carried out.


Electric transformers are available in countless configurations. A few examples of these configurations include pulse transformers, zig zag transformers, toroidal transformers, step down transformers, step up transformers, auto transformers, low voltage transformers, high voltage transformers, 3-phase transformers, instrument transformers, isolation transformers and inverters.

Pulse transformers are used to create electrical surges, or pulses, that are utilized in applications such as radar communication, particle acceleration, and camera flashes.

Zig zag transformers are 3-phase transformers that are used for designated purposes such as regulating harmonic currents, and providing earthing for ungrounded electric systems.

Toroidal transformers are ring-shaped, and are known for their space efficiency and their ability to reduce electromagnetic interference. Its inductors regulate the amount of AC flow into an electrical device, and also reduces high frequency noise.

Step down transformers feature fewer secondary coil windings and convert high voltages to low voltages.

Step up transformers do the opposite, as they feature a higher number of windings in their secondary coils.

Auto transformers transfer electricity through conductors that are in contact with one another, and therefore are not isolated from either the load circuit or the source.

Low voltage transformers convert an electrical current into a voltage that is appropriate for appliances such as small electronic devices and dimmer lights.

High voltage transformers, on the other hand, are used in applications such as transmitting electricity from one power facility to another, as well as its points of consumption.

3-phase transformers use three phases to convert electricity.

Instrument transformers, in addition to current transformers, are capable of accurately gauging and monitoring voltage levels as electricity is transferred through the transformer’s primary and secondary coils.

Isolation transformers feature disconnected primary and secondary coils. They disconnect two circuits and allow AC power to move between two devices while the two circuits remain separated. Most configurations of transformers can be classified as isolation transformers, due to their ability to regulate electric transmission by way of induction.

Inverters are able to convert DC voltage, or direct current voltage, to AC, or alternating current voltage.

Advantages of Electric Transformers

One of the biggest advantages of electric transformers is the fact that they are the safest avenue for conducting electricity between circuits. In addition, electric transformers are so efficient and powerful that they power anything from an electric razor to kvas for entire communities. They are likewise versatile in physical size and can be small enough to fit into a household appliance, or large enough to be fenced in an entire power facility.

Also, electric transformers can not only change the voltage of electrical currents, but also isolate different parts of a current.

When there is a difference in voltage between a power supply and an electric device, electric transformers are essential. If the voltage is too high or too low, it can lead to serious problems. Using a voltage that is too high can cause the device to fail, if not destroy it entirely. More severe results of excessive voltage include fire or electric shocks. Devices can also fail due to a deficiency of voltage.


There are many accessories that may benefit your electric transformer application. Examples include fuse boxes, fuse box covers, fuse holders, fuse clips, jumper links, fuse pullers, terminal covers, lug kits, weather shields and more. To find out what accessories might work for you, talk to your supplier.


Some of the organization/association standards to which your electric transformers may need to adhere include those put out by NEMA (National Electrical Manufacturers Association), IEEE (Institute of Electrical and Electronics Engineers), ASTM International, ANSI (American National Standards Institute) and ISO (International Standards Institute).

In addition, many industries enforce standards based off these or other standards. Examples of these industries include military and defense (Mil-Specs), healthcare (FDA), automotive, transportation (DOT) and more. Find out what specifications your industry requires and/or recommends by talking to your industry leaders and applicable governmental offices.

Things to Consider

Before purchasing an electric transformer, you need to find a manufacturer. Finding the right manufacturer is not always easy, as there are so many options out there. To help you discern, we have gathered a list of the best of the business and provided their contact info on this page. Before you look them over, if you have not already, put together a list of your specifications, requirements, questions, and concerns. Do not forget to jot down info like your budget, your deadline, your delivery preferences and post-delivery support. Once you have put your list together, you can start browsing the electric transformer suppliers we have provided for you. As you browse, compare and contrast their services and products with your needs. Choose three or four and give them a call. After you have discussed your application with each of them, look at their service offerings, products, prices, and customer service. Then, choose the right one for you and get started. Good luck!

Electric Transformer Informational Video