Dual Voltage Transformer

A dual voltage transformer is a type of transformer that has two different output voltages. A Dual voltage transformer has two separate winding that may be used as a single winding or can be connected in a series to get different voltage levels. When we connect the transformer winding in the series the number of turns increases and thus we get a higher voltage.

Why do we need two voltage levels? The electrical appliances operated in different regions may have different voltage standards and to meet user’s requirements, equipment manufacturers provide a dual voltage transformer with equipment so that users can select the voltage according to their electrical system requirements.

Construction and Working

A dual voltage transformer has a primary winding, a secondary winding, and an iron core similar to that of a standard transformer. However, a dual voltage transformer has two primary winding and two secondary winding that can be connected in a series connection. When you connect the winding in the series connection, the number of turns increases, and as a result, the voltage across the winding increases.

Let us understand the working of the transformer with an example. The equipment needs to operate in different regions with 120 volts and 240 volts of power supplies. Then, you need two primary winding with each winding rating of 120 volts. If you use any of one winding, you can use it for 120 volts supply system. If the supply system voltage is 240 volts, you need to connect both primary windings in series. By connecting the primary winding in the series, you will get 120 +120 =240 Volts.

There are two secondary winding in the dual voltage transformer. Suppose the voltage rating of each secondary winding is 12 Volts. If you connect both secondary windings in the series, you will get 12 + 12= 24 Volts. The schematic diagram of the series arrangement is shown below.

dual voltage transformer-winding connected in the series

If you want to get 12 volts,4 amperes from the dual voltage transformer, you need to connect the primary and secondary of the transformer in parallel connection. When you connect the primary winding in parallel, the primary winding receives 120 volts. Similarly, when you connect secondary winding in parallel you will get 12 volts. Here, the total current rating of the transformer secondary becomes 2 +2 = 4 Amperes. The circuit diagram of the parallel connection of the transformer winding is shown in the below figure.

dual voltage transformer winding connected in parallel

Identification of a dual Voltage Transformer

You can easily identify whether the transformer is a dual voltage transformer or a normal transformer. The rating of the normal transformer on the nameplate is engraved as 24V @ 2 A., it means the secondary voltage is 24 volts and it can deliver 2 amperes current. The rating of the dual voltage transformer is mentioned as 12 V @ 4 A – 24 V @ 2 A. It means you can get two different voltages 12 volts and 24 volts and, the corresponding current rating is 4 amperes and 2 amperes.

Applications of a Dual Voltage Transformer

The dual voltage transformer is used for the following applications.

1. Conversion of One Voltage Level to Another

When the power source has a different voltage level than that of an existing voltage level of the electrical system. Now, if you want to utilize that power source then we need to install a dual voltage transformer that can function with both voltage levels.

2. Electrical Appliances

The electrical appliances may need different voltage levels to operate in different countries. For example, the voltage level in the USA is 120 Volts, whereas the operating voltage in India is 230 volts for domestic applications. Therefore, the equipment must have voltage selection features to operate in different countries.

Therefore, electrical appliances like hair dryers, electric shavers, and other portable electronic devices are fitted with dual voltage transformers that allow these devices to operate anywhere in the world.

3. Transportation

The transportation applications like electric cars and trains require different voltage levels to operate. A dual voltage transformer can be used to convert the voltage level as per the rated voltage level of the equipment.

4. Renewable Energy Systems

Renewable energy systems like wind turbines and solar panels often generate power at different voltage levels. The dual voltage transformer can be used to convert the renewable voltage level to the appropriate level for use in homes and businesses.

5 Industrial Applications

Different electrical machines may require different voltage levels to operate. The machine can not be operated until you provide the rated voltage to the machine. The dual voltage transformer can be used to get the rated voltage for machine operation.

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