What are 3 phase auto transformers?

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In principle, transformers are used to increase or decrease the voltage in a circuit according to the principle of electromagnetic induction, when the available mains voltage does not match the input voltage required for the operation of the device. There are a large number of types of transformers that are used for different applications and differ in their design and mode of operation. However, the basic principle of any transformer remains essentially the same: a primary and a secondary winding are wound around a core and are responsible for transmitting electrical energy through a changing magnetic field.

However, there is a special type of transformer that has only one winding instead of two separate primary and secondary windings. This is a three-phase autotransformer in which a single coil acts as both primary and secondary winding. Unlike conventional transformers, the windings of a three-phase autotransformer are not electrically insulated, but induction occurs by self-induction. Since the terminals of the primary and secondary windings are connected both electrically and magnetically, the rest of the operation remains the same as in a conventional transformer.

Application of 3 phase autotransformer

3 phase autotransformer are used in power transmission systems, power distribution systems, audio systems, asynchronous motors, and railway systems. When a voltage drop occurs on distribution lines, these transformers can be used to eliminate this drop. In addition, more current is needed to start an induction motor, so the voltage drops. Therefore, these transformers increase the voltage when the motor is started.

Advantages of using 3 phase autotransformer

Three-phase autotransformers are smaller and cheaper than conventional transformers of the same power rating, so less space is needed to install the transformer and costs are reduced.

Three-phase autotransformers have less flux, which allows for better regulation, and copper losses are also lower, making them more efficient.

Disadvantages of using 3 phase autotransformer

Three-phase autotransformers have a very low impedance compared to other transformers.

Since there is no isolation between the primary and secondary windings, these transformers cannot be used to reduce very high voltages for small loads.

Three-phase autotransformers need special protection because they are very sensitive to environmental influences.

When buying a 3 phase autotransformer

If you compare all the advantages and disadvantages of a three-phase autotransformer, you can decide whether or not it is suitable for your application. However, before you decide to buy this transformer for your appliance, there are a few things to consider, such as.

Primary and secondary voltage: the primary voltage of the transformer should match the available mains voltage and the secondary voltage should match the requirements of the load connected to the transformer.

Winding material: you can choose aluminum because it is cheaper, but copper windings provide durable, robust, and corrosion-resistant coils that require minimal maintenance.

Power rating indicates the maximum load the transformer can withstand and is expressed in kVA. Select a transformer with a power rating that exceeds its maximum rating.

Frequency – Check the operating frequency of the transformer, as you can only increase or decrease the voltage, but not change the frequency of the supply voltage.

Keep all these considerations in mind and discuss your three-phase autotransformer needs with the professionals at Shuogong Power. You can purchase one of the available transformers or get your own custom transformer from this experienced and competent 3 phase autotransformer manufacturer and supplier in China.