Understanding Variable Transformers

Variable transistors are used to control electrical voltage and power through simple and reliable operations. Used for speed control in AC and DC motors, heater control, light dimming, and other applications, variable transistors have become a staple as a practical electronic component. In this blog, we will discuss everything you need to know about variable transformers, including their design, function, and various applications.

Every variable transformer contains a magnetic core shaped like a donut. This component, colloquially referred to as a toroidal core, is paired with a copper winding that surrounds it. They also contain a carbon brush that directly contacts an exposed section of the copper wiring, allowing for a voltage range of 0V to the maximum rated output. These transformers are explicitly designed to be efficient, with power losses only occurring 1-2% of the time. They also have the ability to produce the same output with half of the standard voltage. For example, many models requiring a 240V input will also work properly with 120V cables. The most significant limiting factor for most variable transformers is temperature requirements, which demand a decrease in output over the maximum temperature rating.

While the majority of variable transformers are rated for inputs of 240V or 120V, there is also an option to create a wye connection between two or more units, allowing for inputs up to 480V. This application is called ganging, and it may be implemented only if the system contains a ground between the source and the ground, or if the loads can be balanced on either side to prevent a damaging current. Under normal operating conditions, the input voltage may increase or decrease by up to 10%, which is within the tolerable range for most applications. However, if a component requires a more narrow voltage window, a buck-boost device may be added to the system to help regulate input. These elements may also be installed if the application requires a less-than-standard input voltage.

Regardless of the application, it is necessary to create an adequate cooling system to accompany the transformer. Most low-power models cool naturally by means of convection and heat dissipation from radiation. However, high voltage transformers commonly require forced-air cooling, forced-oil cooling, or direct-water cooling. If a system does not achieve proper cooling during operations, the effect is dramatic, with over 30% of transformer failures directly caused by overheating. When using oil-based cooling techniques, it is important to choose a medium that is compatible with the facility safety regulations, which usually mandate the oil to have flame-resistant properties.

Variable transformers are used around the world to safely regulate electrical current before it reaches consumers. They are also commonly employed in home appliances, such as heaters and refrigerators. Additionally, variable transformers are the only dimming mechanism that may be used for incandescent light bulbs since these devices depend upon AC voltage. Electric motors are also controlled through a similar mechanism to the lightbulb. Finally, variable transformers are implemented in circuit testing, allowing the operator to adjust the voltage to any level within the operating range of the transformer.

When you are in need of reliable variable transformer components or any other electrical devices, choose Infinite Industrials to meet your requirements with ease. Owned and operated by ASAP Semiconductor, we offer customers an end-to-end purchasing solution for over 2 billion new, used, and obsolete items. We are an AS9120B, ISO 9001:2015, and FAA AC 00-56B accredited enterprise with a NO CHINA Sourcing policy, meaning you can shop with confidence knowing that you are receiving the highest quality components possible. Contact our team with any questions or begin the purchasing process immediately by using our Instant RFQ service to experience the future of parts purchasing.