8 Questions to Ask Before Choosing a Transformer

Article By : Peter Scully

There are a number of questions to help you choose the right transformer for your industrial application.

Choosing the right transformer for your industrial application really can transform the efficiency of your product and help extend its lifespan. Sometimes your project may require a standard low/high frequency transformer, however depending on you specific requirements, your product may benefit from custom transformers which are custom designed to be fit for purpose.

Before making the decision, there are a number of things to take into consideration and with that in mind, here are eight questions to ask to help you choose the right transformer for your industrial application.

Double-check the number of phases required

Although three phases is the standard for industrial applications, if you’re just using small-scale machines, similar to domestic appliances, then one phase may be sufficient.

Choose the appropriate voltage

As the input and output voltages are dependent on the power supply and equipment you are using (respectively), you ideally want to know both before you make a final choice of transformer, however, in certain situations, there will be standard input and output voltages which are essentially taken as given and if you know what they are, it can be reasonable to work from them. You may, however, want to hold off making an actual purchase until you are 100% sure of what the relevant voltages will be.

Determine the maximum load

You will need to know this to select a suitable kVA rating. In the context of transformers, the kVA size is determined based on the primary or secondary winding voltage and the amperage.

Confirm the purpose of the transformer

Typical uses would include isolation transformers, K-factor or as an auto-transformer

Scope the working environment of the transformer

Even if the transformer is intended for use in the safest of indoor locations, it is still important to know the working ambient temperature of the area in order to ensure that the actual operating temperature can be taken into account during the design process. The key phrase in that sentence is “working temperature”. It is important to remember that buildings in use tend to be warmer than empty buildings and in some cases that difference can be substantial. Sometimes this will be obvious (for example, in a commercial bakery) but even much lighter industrial environments can generate much more heat than you might expect.

In addition to thinking about heat, you will need to think about whether or not the transformer will be exposed to the elements in any way. Why this is most obvious in outdoor environments, it’s not impossible in indoor ones, for example, if the transformer is to be used in an area such as a loading bay, it may be appropriate to use a transformer designed for outdoor use and which is likely to be liquid-filled in order to protect the winding from the elements.

As a final point, if the transformer is to be used in a hazardous environment, it may need to comply with an additional set of regulations, such as being APEX approved.

Check what approvals are required

On that point, industries will often have their own standards and approvals such as Lloyds Register, DNV and Atkins, which will need to be met.

Choose an appropriate physical size of transformer

Although transformers are generally designed around standardized core sizes, it is often possible to create non-standard designs for non-standard situations.

Decide on the wire configuration

Standard three-phased transformers generally use one of three standard configurations: star, delta and interconnected-star, but there is usually some degree of flexibility in the exact implementation.

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