Last updated: August 17, 2021

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Sometimes we have no choice but to use tools and devices imported from other countries, which is not always easy, as many countries work with different voltages which can result in equipment not working when plugged in or worse, being damaged completely.

It is exactly for these occasions that a voltage transformer is so useful, as it allows us to use tools whose electrical requirements are different to those we have in our homes and workplaces, allowing us to make the most of imported equipment without fear of damage.

We bring you this complete shopping guide to identify and buy the best transformers on the market. To make this guide we looked for the qualities that most demanding buyers are looking for in transformers, and researched the best places to buy them, all to help you in your purchase.




Summary

  • A voltage transformer is a device used to convert the current provided by the electrical service, in order to use electronic devices that are incompatible with the current normally provided by the mains. They are widely used in industrial applications and with imported tools.
  • Most current transformers come in two forms, 220 to 110 and 110 to 220. The 220 to 110 transformers are called step-down transformers and their function is to lower the voltage, the 110 to 220 transformers are called step-up transformers and are responsible for raising the voltage. There are also transformers that perform both functions.
  • You should know what type of current the equipment you need to use a transformer with works with, so you will know the type of transformer you will need to use. You should also know the wattage (W) of your equipment, as it is advisable to buy a transformer whose wattage is at least 3 times that of your equipment.

The best Transformer: Our Picks

Buying Guide

It is very important that you know how current transformers work, as they are delicate equipment that can be dangerous if mishandled. In this section we will tell you what transformers are used for, what the different types are and where you can buy them.

If you buy a transformer for use with power tools, make sure it can provide at least 3 times the wattage required by the tool. (Photo: Elnur Amikishiyev / 123rf.com)

What is a transformer and what are its advantages?

A transformer is a tool used to adapt the current level of an electrical network to another level. They serve by connecting to the mains, then transforming the level of that power and finally transmitting that power to another electrical device plugged into the transformer. Most of them work with 220 and 110 currents.

These tools are vital wherever there are tools whose power requirements are different from those provided by the mains, so they are often indispensable in workplaces where a wide variety of tools are used, in homes where imported devices are used, and during emergencies.

Advantages
  • Increase equipment compatibility
  • Easy to install and use
  • Different current levels
  • Useful in emergencies
Disadvantages
  • Incorrect use is dangerous
  • Costly
  • Few opportunities for use

Step-up, step-down and dual transformers - what should you look out for?

Since most electrical networks work with 110 and 220 currents, there are three types of transformers to work in those cases where you need to step up or step down the current. It is important that you are aware of the different types of transformers so that you know which one you need to buy.

  • Boost transformer: They are used to boost the current from 110 to 220 volts. Because they raise the power emitted by an electrical network, they are used to give power to tools that work with 220 volts, such as those used in European countries, Asia and Africa.
  • Step-down transformer: These are used to reduce the current emitted by the power plant, and reduce the voltage from 220 to 110 volts. These transformers are used for tools whose energy requirement is less than that emitted by the mains, and are used in European countries to use American equipment.
  • Dual transformer: Also called universal transformers, they can operate by increasing the voltage from 110 to 220 volts, but also by reducing the voltage from 220 to 110 volts. This is the most versatile type of transformer as they can operate with all types of power grids and tools. Some step-up transformers can operate in this way.
Step-up transformer Step-down transformer Dual transformer
Switching current 110 to 220 220 to 110 220 to 110 and 110 to 2204
Common uses Tools imported from Europe, Africa and Asia In Europe to use American tools All kinds of applications

Buying Criteria: Factors that allow you to compare and rate different Transformers

Although using a transformer is as simple as plugging it in and activating a pair of cigarette lighters, you should not take them too lightly, as incorrect use of these tools can be dangerous for you, the transformer and whatever is connected to it.

To help you choose a transformer that you can use with confidence, this section will tell you all the buying factors you should consider when purchasing transformers. We'll show you both how to identify good transformers and what you need to know to choose the right one.

Current required

The current used in Mexico is 127 or 110 volts, so you will rarely need a step-down transformer, unless you are working in a location whose energy properties are different from those provided by the power plant, or you plan to use American tools on another continent.

It is always good to read what voltage is accepted by the equipment you buy to see if it is compatible with your mains supply - some equipment, such as phone chargers, laptop power adapters and hairdryers can operate on 100 to 240 volts, so do not need a transformer.

High current

Don't worry if you can't find a transformer for 127 volts, as transformers and electronic equipment often work on voltages close to the designated voltage. For example, a 110-volt TV will work on a 127-volt mains and a 110 to 220-volt transformer will boost the current from 127 to 220 volts.

To give a clearer example, let's say you import a TV or a tool from Germany, which is a country where the equipment works on 220 volts, if you try to use it at home it will not work, so you will need a step-up transformer that adapts the 127 volts to be compatible with 220 volt equipment.

Reduced current

In the unlikely event that you need a step-down transformer for use in Mexico, you can buy a 220 to 110 volt transformer without worrying about whether the equipment is 110 or 127 volts. As a reminder, the current in Mexico is either 127 or 110 volts, so you will rarely need a step-down transformer.

Power requirements

Not all step-down and step-up transformers are the same, as they have different wattage levels, which can be found by their numerical designation followed by a W. This is a factor that must be added to the power requirements of the transformer. This is a factor that you must take into account, as the correct operation of your equipment with your transformer will depend on it.

  • If you have a transformer whose wattage is lower than what your equipment needs, it will not work properly. In the event that a transformer has a wattage much higher than your equipment uses, you will not have a problem, as it will provide only what is necessary for the equipment without overloading it.
  • Calculate the wattage: If your tool does not say how much wattage it uses, but it does provide its amperage and the voltage it needs, you can make the following calculation: V (Voltage) x A (Amps) = W (Wattage), e.g. a tool that works on 110 volts and has an amperage of 5 Amps will be 550 W, i.e. 110 V x 5 A = 550 W.
  • Wattage recommendation: It is advisable to buy a transformer whose wattage is 3 times the wattage required by the equipment you will be using on it. This is because some equipment such as televisions and power tools, use three times the power to turn on, thus raising the wattage it will take from a transformer to start working.

For example, if you need to use a 400 W power tool, the transformer you must buy must have a minimum wattage of 1200 W. So if you will be using a power transformer with powerful equipment, you must choose a transformer capable of providing the necessary wattage.

Voltage regulator

In certain places where voltage often varies during emergencies, such as earthquakes or thunderstorms, power dips can occur where equipment operates at low or very low power. This is very dangerous for the equipment as the return of power can be sudden and can damage the equipment.

If you want to take extra precautions to protect the integrity of your electronic equipment, a transformer with a voltage stabiliser will protect your equipment against power surges and dips. If you live in an area prone to constant power swings, it is best to purchase a transformer with a stabiliser.

Additional features

Now that you know everything you need to know to use these tools, it's time to learn about those little things that are sometimes overlooked. You don't need to look for the following features on your transformers, but it's good to keep them in mind to avoid bad surprises.

Type of plug

Let's say you imported a tool from the UK, bought a 220 to 110 power transformer whose wattage is more than enough for it to work properly, but it turns out that when you plug it in, it's not compatible!

The plugs or sockets used in other countries may be different from the one used in Mexico, so it is good to keep this in mind if you will be using imported electronic equipment. Don't worry if the above example happens, as you can fix it with a simple plug adapter or by buying a transformer with a compatible plug.

Number of plugs

If you plan to use different tools on a transformer, it is a good idea to consider how many plugs the transformer has. Keep in mind that the number of plugs will increase both the size and the price of the transformer.

Short-circuit protection

Some transformers have a type of protection called a "circuit breaker", which works by shutting down the equipment when there is a danger of short circuits occurring. This will prevent permanent damage to both your electronic equipment and the transformer by preventing damage to its fuses.

Quiet operation

Don't be surprised if the transformer you are interested in produces noise, as this is normal. If, for example, you will be installing your transformer in a room or studio, and you don't want it to make a lot of noise, look for one that is designed to work quietly.

(Featured image photo: Serhii Datsinko /123rf.com)

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