A transformer is an electrical device designed and manufactured to step voltage up or step down. Electrical transformers operate on the principle of magnetic induction and have no moving parts. As a transformer transforms the voltage on the input side to the voltage required by the device or equipment connected to the output, it inversely increases or decreases the current flow between the different voltage levels. An electrical transformer exemplifies the law of conservation of energy that says energy can neither be created nor destroyed, only transformed!

An Electric Transformer’s Basic Construction

Electrical transformers, having no moving parts or highly sensitive essential components or materials, are by nature remarkably reliable and durable pieces of equipment. A well-designed, quality-built transformer can be expected to function continuously and trouble free for years under rated operating conditions. Rated operating conditions refer to the specified conditions under which a transformer is designed to operate safely and efficiently. These conditions include factors such as the voltage and frequency of the power supply, the ambient temperature, and the maximum load that the transformer can handle.

In its most basic form, an electrical transformer consists of two coils or windings—input and output—of electrically conductive wire wound around an electrical grade steel core. The coils or windings in an electrical transformer are the essential components that allow the transformer to convert electrical power from one voltage level to another using the principles of electromagnetic induction. They are two sets of insulated wires wound around a core, typically made of laminated steel. The input coil, also known as the primary winding, is connected to the power source, while the output coil, also known as the secondary winding, is connected to the load.

Other construction aspects on an electrical transformer includes

  • Core Material
    • The core of an electrical transformer is typically made from laminated sheets of electrical grade steel, which are stacked together and insulated from each other. This laminated construction helps to reduce eddy current losses and increase the efficiency of the transformer.
  • Insulation
    • The windings of the transformer are insulated from each other and the core using materials such as varnish, enamel, or mica. The insulation helps to prevent electrical arcing and ensures that the transformer operates safely and reliably.
  • Tap Changers
    • Some transformers include tap changers, which allow the number of turns in the windings to be adjusted. This can be useful for regulating the voltage output of the transformer or for compensating for changes in the input voltage.
  • Cooling Systems
    • Transformers generate heat during operation, reducing their efficiency and shortening their lifespan. To prevent overheating, transformers are often designed with cooling systems, such as fans or oil-cooled radiators, to dissipate the heat.
  • Enclosure
    • Transformers are typically housed in an enclosure made from metal or plastic. The enclosure protects the transformer from external damage and provides a barrier to prevent accidental contact with the high-voltage components inside.

Types of Electrical Transformers

Electrical transformers come in various types, each designed for a specific purpose. The most common types include step-up and step-down transformers and isolation transformers, each of these variations is explained below.

  • Step-up Transformers
    • These transformers increase the voltage of an AC power supply. They are commonly used in power transmission systems to step up the voltage for long-distance transmission and then step down again for local distribution.
  • Step-down Transformers
    • These transformers decrease the voltage of an AC power supply. They are used to reduce the voltage for use by homes and businesses.
  • Isolation Transformers
    • These transformers isolate electrical circuits from each other. They prevent electrical shocks by providing a barrier between the primary and secondary circuits.

Other types of transformers include current, voltage, distribution, and power transformers. Each type of transformer has its unique design and construction and is used for a specific application depending on the electrical system’s requirements.

An Electric Transformer’s Basic Function

When the primary coil receiving the voltage (input) is energized, the core is magnetized, and voltage is subsequently induced, or stimulated, in the output or secondary coil. The change in voltage (voltage ratio) between the primary and secondary coils is dependent on the turns ratio of the coils. When the transformer is loaded—that is, when the device or equipment the transformer is designed to power is connected and the transformer is energized—the “load” begins to draw current (quantified in amperes, or amps) at the voltage the transformer was designed to deliver.

Applications of Electrical Transformers

Electrical transformers have a wide range of applications in various industries and sectors. Here are some of the most common applications of electrical transformers:

  • Power Transmission and Distribution
    • Electrical transformers are essential components of power transmission and distribution systems, allowing high-voltage power to be generated and transmitted over long distances with minimal energy loss. They are used to step up or down the voltage levels of power supplies, making it possible to transmit electricity over long distances to homes, businesses, and industries.
  • Industrial Applications
    • Transformers commonly supply power to machinery and equipment. They are used to power motors, lighting systems, heating and cooling systems, and other equipment. They also control voltage levels and provide electrical isolation between circuits.
  • Renewable Energy
    • Electrical transformers, such as wind and solar power plants, are important in renewable energy systems. They are used to step up the voltage of the generated electricity, making it possible to transmit it over long distances to the power grid.
  • Power Tools
    • Power tools are commonly used in construction, manufacturing, and other industries to perform various tasks such as cutting, drilling, grinding, and sanding. These tools typically require a source of electrical power to operate, and electrical transformers play an important role in providing the necessary power. Electrical transformers can also be used to provide isolation between the power source and the tool, enhancing safety and preventing electrical shock. Isolation transformers are commonly used in power tools and other electrical equipment to isolate the input and output circuits while allowing power to be transferred efficiently.
  • Electronics
    • Transformers are used in various electronic devices, such as audio equipment and televisions. They convert AC power to DC power and regulate voltage levels within a circuit.
  • Medical Equipment
    • Electrical transformers isolate electrical circuits and ensure patient safety. They are used in MRI machines, X-ray machines, and surgical equipment.
  • Transportation
    • Transformers are used in transportation systems, such as electric trains and trams. They are used to step up or down the voltage of the power supply, making it possible to power the electric motors that drive the vehicles.

At Johnson Electric Coil Company, we offer comprehensive engineering, design, and manufacturing services to deliver highly efficient custom electrical transformers and inductors. The design and manufacturing services we offer are some of the most wide-ranging in the industry.

If you are searching for a custom electrical transformer, or custom inductor solution, our team at Johnson Electric Coil Company can help. Our experience in the industry spans more than eight decades and we are here to serve all of your electrical transformer needs for decades to come.

To learn more about our transformer products and capabilities related to your applications, give us a call today at 800.826.9741 or fill out our contact form.