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    The basics of electrical transformers.

    A transformer takes electricity of a certain voltage and transforms it into electricity of another voltage. All transformers function on an alternating current, and the only thing that changes is the voltage while frequency and amperage remain the same. They can be installed either indoors or outdoors depending on the application, though some may need to be installed in a vault for safety reasons. Different types of transformers are used across commercial, industrial, institutional, and residential applications, so it’s definitely not one size fits all.

    Depending on your needs and specifications, you may need a dry-type transformer or a liquid filled transformer, a low voltage or a medium voltage transformer, or maybe you need a custom solution. That being said, always make sure you get the unit that’s right for you. Below you’ll find some helpful specs that will guide you when you’re buying your transformer with Bay Power.

    What do I need to know about my transformer?

    Transformers come in a wide variety of shapes, sizes, and specifications, so getting the right unit may seem a little bit intimidating. However, knowing some of the following information will help you get started on the right foot when looking for your transformer.

    • kVA (kilovolt amps)
    • Single-phase or three-phase
    • Primary voltage
    • Secondary voltage
    • Indoor or outdoor
    • Desired amps at secondary side
    Same-day shipping available
    24-hour emergency support
    Global supplier network
    1-year Warranty

    A Bay Power transformer is a quality transformer.

    Bay Power offers an extensive selection of all types of transformers, including buck boost, dry type, liquid filled, low voltage, medium voltage, single phase, three phase and more. Take advantage of our vast selection of transformers from top transformer manufacturers. You can always count on Bay Power for the best in performance, efficiency, and quality.

    Low Voltage Transformers

    Low voltage transformers are used in low voltage applications under 1kV (or 1000V). They are most commonly found in residential and commercial applications, though they can be used in low voltage industrial applications as well. Low voltage transformers can either be magnetic or electronic, with electronic transformers being more compact and a good fit for smaller applications, while magnetic transformers are better for heavier electrical loads.

    Medium Voltage Transformers

    Commonly used in industrial and commercial applications, medium voltage transformers are rated for 600V applications and up. MV transformers are available in dry-type, liquid-filled, vacuum pressure encapsulated (VPE), or vacuum pressure impregnated (VPI).

    Buck Boost Transformers

    Buck-boost transformers are dry-type transformers, and are used to raise or lower the supply voltage in small increments. They come in a wide variety of voltage ratings and are commonly used to power low voltage circuits or in any application with a secondary voltage between 12-48 volts. They are compact, lightweight, and can be used indoors or outdoors, depending on the model. All of our buck boost transformers comply with NEC standards.

    Dry-Type Transformers

    A dry type transformer is a static device that uses a specialized insulation system to keep cool. Dry-type transformers are a safe and reliable option for indoor installation across both commercial and industrial sectors, although they can also be used outdoor as well. They serve a wide variety of applications including motors, heaters, air conditioners, as well as larger distribution systems.

    Oil & Liquid-Filled Transformers

    Oil and liquid filled transformers are commonly used in industrial applications, built to withstand harsh conditions and heavier electrical loads. They can be filled with a selection of different liquids including mineral oil, silicone, hydrocarbon fluid and more. Compared to dry-type transformers, they are advantageous if you need to handle higher loads at high voltages.

    Drive Isolation & SCR Transformers

    Drive isolation transformers (or DIT’s for short) are designed to specifically handle the heavy demands and common short circuits associated with silicon controlled rectifier applications (or SCR for short). Common sizes for drive isolation transformers range from 5 to 600 horsepower.

    Custom Transformers

    Custom transformers are specially designed, custom-built products that meet a specific set of requirements. Custom transformers are often built for industrial and commercial sectors but can also be built for residential establishments as well. Buck boost transformers, low voltage, medium voltage, 3 phase transformers and single phase transformers can all be custom built with custom designed wiring configurations.

    Single Phase Transformers

    Single Phase Transformers

    A single phase transformer consists of two sides: a primary side and a secondary side. The primary voltage “accepts” or takes in power, while the secondary side delivers the power at the preferred voltage. A single phase transformer operates only on the voltage applied to the primary side. Single phase transformers are used throughout a variety of applications, and come in low voltage, medium voltage, buck boost, and industrial models.

    3-Phase Transformers

    3-Phase Transformers

    3 phase transformers are commonly used for heavier industrial applications and they are able to handle 3 different AC voltages and currents. A 3 phase transformer essentially functions the same as a 3 single phase transformers, if you connect the primary and secondary windings of 3 single phase transformers to each other. Common ratings of 3 phase transformers include 30 kVA, 45 kVA and 75 kVA

    Distribution Transformers

    Used to step down voltages, distribution transformers deliver electricity and provide safe and practical voltage levels. Unlike isolation transformers, distribution transformers are meant to deliver electricity while protecting circuits, while the former is used to protect electrical equipment, sometimes in cases of emergency.

    General Purpose Transformers

    Common uses for general purpose transformers include alarm systems, motor control, industrial lighting, and HVAC systems. They are best used for single phase, general purpose industrial applications, and other lighter duty loads.

    Industrial Transformers

    Industrial Transformers

    Industrial transformers work the same as any other transformer, but are built to withstand the heavy stresses, voltages, and demands of industrial applications. Buck boost transformers, single phase, three phase, K-Factor, and oil or liquid filled transformers are all used across a variety of industries.

    K-Factor Transformers

    K-Factor transformers are a specialized type of transformer that are used to withstand non-linear loads, as well as the heavy harmonics associated with industrial applications. Harmonics can not only increase your energy costs while decreasing your efficiency, but can also potentially damage your electrical equipment. The higher the K-Factor, the higher the harmonic load the transformer is able to withstand.

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    Why Bay Power

    Sell to Us

    Sell to Us

    Fill your wallet, not the landfill.

    Have any old or unused Transformers lying around? Don’t get rid of them just yet. While we stock a wide range of quality electrical products and solutions, both new and reconditioned, we also buy back your unwanted equipment. So, before deciding what to do with your old Transformers and components, have one of our expert technicians take a look to see if we can save a few parts, save the environment, and save you some cash.

    Sell to Us



    Great service shouldn’t end after the purchase. We pride ourselves on the relationships we build with our customer-first mentality and the quality of our Transformers and components. That’s why we offer a 1-year replacement warranty on all of our electrical products and solutions from the top manufacturers. Because when you buy with Bay Power, you buy with confidence.

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    Buying Options

    Product Condition FAQ

    We are proud to stock a variety of competitively priced, new and reconditioned components from the leading manufacturers of Transformers.


    Thanks to our extensive inventory of Transformers and components, our resourceful and expertly trained staff will always be able to get the products that you need. Through our extensive network of suppliers, we are able to carry and acquire a huge variety of electrical products and solutions, so chances are if you need it, we can get it.


    Bay Power’s priority is providing you with reliable, high quality electrical hardware. That’s why our mission is to make sure our reconditioned electrical products and solutions function as perfectly as the day they were built. Because while the quality is high, the cost of Transformers shouldn’t be.

    New Surplus

    Our selection of new surplus Transformers may not arrive brand new in a box, but they function just as well, and have never had electricity run through them. All of the quality, none of the packaging, always with our 1-year replacement warranty.