How to Select a Transformer

The application and load are two of the most important considerations when choosing a Transformer. When making a selection, you should carefully consider all factors to ensure that both primary concerns can be met. In managing electricity infrastructure, all needs must be wise and with quality products. Then MGM Transformers can help to supply varying secondary voltages to externally connected loads. You can find quality electrical and lighting products at the MGM Transformer Company.

To borrow a cliché, smaller transformers are usually easier to find. The unit can be picked up quickly if it has a kVA rating greater than the anticipated load. A large unit that is larger than the expected load can often be picked up quickly. However, large units for electrical utility systems, which are part of large distribution networks, are more costly to buy. Thus, the evaluation process becomes more thorough and complex. Pacific Crest Transformers boasts over 90-years of industry experience. This checklist will help you make an informed decision.

There are three important questions that can impact your choice.

Is the unit able to take the expected load?

Can the unit handle an increased load?

Is the unit designed to last for at least 10 years? What are the initial, operating, and maintenance cost?

Evaluation Factors

A series of evaluation factors will typically determine the cost and capability of the transformer.

1. Application of this Unit

Transformer requirements change based upon the application.

For example, the steel industry requires a lot of power to function. So load losses must be minimized. This is why a particular type transformer construction that minimizes copper loses is better suited. Wind energy applications are subject to high output power fluctuations. The transformers used should be able handle these surges without any problems. Power transformers that are able to supply consistent, correct energy for smelting are crucial. However, in the automotive sector, short-term overload capacities are a must. For textile industries that use motors of different voltage specifications, they will require intermittent or tap-changing transformers. Horticulture requires high-performance units with variable voltage to suit their needs.

These examples are intended to show how important placement and type of load (amplitude of linear loads, duration, and extent of non-linear, linear loads), is. If these parameters don’t work for you, then it will be necessary to find a manufacturer capable of customizing the operating characteristics, sizes, and other attributes according to your specifications. Pacific Crest regularly builds custom transformers for unique applications.

2. Insulation Type (Liquid–Filled Type or Dry Type)

While debate continues about the relative strengths of each type of transformer, there are some performance characteristics which have been accepted.

o Transformers that are liquid-filled have higher efficiency, greater overload capability, and a longer expected life span.

o While liquid-filled units work better to reduce hot-spot temperature, they pose a greater risk for flammability than dry ones.

Unlike dry-type units, liquid-filled transformers often require containment pipes to prevent fluid leakage.

Dry type units are used for lower ratings (the point of changeover being 500kVA or 2.5MVA). You should also consider the location: will it be indoors serving an apartment/office building or outdoor serving an industrial load. Outdoor transformers of higher capacity are almost always filled with liquid. Indoor units have lower capacities and are generally dry. Dry types are often enclosed with louvers or sealed.