Top Questions to Consider When Choosing a Transformer

There are many types of transformers and choosing the right one for your worksite is very important. The cost of your transformer can easily vary 50% for the same size transformer based on the type of transformer, materials used, available accessories selected and required testing. Not only do you need to determine the size of the load and voltage to be transformed but also the type of load, location of the transformer and how it is to be applied within its applied facility.

To make this process easier, we have put together an easy guide of questions to consider when selecting a three phase transformer. Follow these questions to make the best selection.

Is it a liquid filled or dry type?

If you are looking for liquid filled, ask the following.
1. What size kVA?

2. What is the type? Compartmental Padmount or Substation
3. Determine primary voltage: Delta or Wye?
4. Determine secondary voltage: Delta or Wye?

Once you have chosen a type liquid filled transformer, there are several more steps to help finalize your decision. For a Padmount type, these include determining live front or dead front, loop feed or radial feed, which winding material and the temperature rise. Lastly, for a Substation type, decide which enclosure, temperature, if forced air cooling is necessary and lightning arresters are required.

If you are looking for a dry type, ask the following.
1. What size kVA?

2. What is the type? General Purpose, Drive Isolation, Substation or K-Rated
3. Determine primary voltage: Delta or Wye?
4. Determine secondary voltage: Delta or Wye?
5. What is preferred winding material? Aluminum or Copper
6. What temperature rise? 115 degrees Celsius rise or 115 degrees Celsius rise; etc.
7. What is the enclosure type? Nema 1, Nema 3R or Nema 12 (If no enclosure, unit will be core and coil.)

Answering these questions will help you pick the best transformer. And, your service provider can use the results to expedite the process.