Power transformers are devices that change the mains voltage to ensure efficient and safe operation of equipment. An autotransformer works similarly to a transformer , but it has a completely different design. Learn how an autotransformer works and how to use it in various devices.
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The basic difference between autotransformers and transformers
As mentioned in the introduction, autotransformers differ from transformers in terms of their construction. The operation of both devices is based on the winding, where the magnetic flux is generated. A standard transformer is made of a primary winding and a secondary winding separated by galvanic insulation.
In an autotransformer, the primary and secondary windings are connected together – there is NO galvanic separation between them. It should be emphasized that the role of both devices is similar and consists in changing the value of the mains voltage. Some sources consider an autotransformer to be a special type of transformer.
What is an autotransformer and what is its use?
Autotransformers are a simple device used to change the voltage level. Its characteristic feature is the lack of galvanic isolation between the secondary and primary sides, which in certain conditions translates into significant economic benefits. The primary and secondary windings are located in one place. This design allows energy to be transferred between circuits using both a magnetic field and an electrical connection. Due to the possibility of working with a fixed or variable transmission and a very good ratio of power and efficiency to size, weight and price, autotransformers are widely used in industry.
In what places will an autotransformer be useful?
Autotransformers are installed where voltage change with low ratio is needed in power grids. They are a more economical alternative to regular transformers. Thanks to the possibility of smooth regulation of secondary voltage, they are widely used in the laboratory industry, allowing for conducting tests requiring power supplies of different voltages.
The autotransformer allows you to control any linear receivers, including electric heaters. Another (although increasingly rare in practice) area of application of autotransformers is the soft start of large, induction drive units. Today, inverters are mainly used for this task.
It should be remembered that an autotransformer will not always be suitable for changing the voltage in an electrical circuit. The device is not suitable for applications such as mining and medicine due to the lack of galvanic isolation, and therefore failure to meet safety requirements.
Basic types of autotransformers on the market
Autotransformers available on the market differ in their method of operation and purpose. The basic types are:
- autotransformers with fixed gear ratio,
- adjustable autotransformers - with the possibility of changing the gear ratio step by step or smoothly,
- single-phase autotransformers - designed for circuits with a voltage of 230 V,
- three-phase autotransformers - designed for circuits with a voltage of 400 V.
For an autotransformer to function properly, it must be precisely matched to the installation parameters and device requirements.
It is worth knowing that there are also different types of transformers: pulse transformers, single- and three-phase, without housing and with housing, designed for DIN rail, portable and others.
We invite designers and installers of industrial automation systems, as well as shops and smaller electrical installation wholesalers to familiarize yourself with the offer of the Onninen wholesaler. The assortment includes products from Breve - a Polish manufacturer of high-quality transformers, autotransformers, regulators, power supplies and chokes. Do you have doubts about which autotransformer to choose? Are you interested in another device, e.g. a power transformer, but you did not find it on our website? Contact Onninen technical advisors!