A shot of the exterior of Corefficient’s facilities with overlayed text “How We Deliver the Best Electrical Transformer Core”

Since our opening in 2016, Corefficient has aimed to develop and deliver high-performance electrical transformer cores with unmatched customer service. Our customers demand the best – and we deliverwith maximized core efficiency based on material selection, geometries, and manufacturing processes.

Our team of experienced professionals work day-in and day-out in our state-of-the-art, ISO-9001 certified facility in Monterrey, Mexico to bring you the best service in North America and beyond.

We’re very proud of the attention to detail that we put into each core – and we know that customer trust paramount in this industry. So, today, we are going to discuss the steps wetake to deliver the best electrical transformer cores in the industry.


Corefficient is, of course, an electrical transformer core manufacturing company, and so we offer a variety of transformer core services. This includes sourcing and testing the highest quality electrical steel available as well as, construction, and testing of the core. The full scope of our manufacturing process makes us a globally competitive transformer core manufacturing company.

When we work with our customers, we follow a simple but effective four-step process:

  • Design
  • Acquire Components
  • Test
  • Deliver


The goal of any transformer design is to optimize efficiency while minimizing losses and costs. Our sales engineers will work with you on a personal basis and take your design and turn it into a reality. Learn more about our design process here!

Additional value-added design services


To ensure the performance of grain-oriented steel materials, Corefficient has invested in a modern rolling heart annealing furnace (continuous) to relieve stresses induced through core manufacturing, and return the material to its original properties.


Cores are delivered in a variety of finishes to promote greater electrical and heat insulation, as well as corrosion protection. To fulfill diverse customer needs, we have an on-site, dedicated paint booth facility to paint and coat cores to our customers’ specifications.


Our goal is to create the most efficient core possible (we’re so dedicated to this aim, it’s in our name!). We incorporate rigorous testing of the core throughout each step of the manufacturing process.

To test our electrical steel, we utilize the following methods. (Click the links below to find out more information on each of the testing methods.

Epstein TestingElectrical steel is measured for core loss and permeability using a Brockhaus MPG 200 automated test system Epstein test frames, multiple Tesla and frequency inputs based on ASTM A717 test method.

Single Sheet Testing (SST)Each coil of electrical steel is measured for NLL (no load losses) and permeability using a modern SST. This equipment is capable of measuring domain refined electrical steel.

Franklin Testing: A unique method of testing single strips of flat rolled electrical steel for surface insulation resistance under predetermined voltage, temperature, and pressure conditions.

Dimensional TestingEach coil of electrical steel is measured for variations in material thickness and width based on ASTM A971 test method.

Once we have ascertained that the material is of exceptional quality, we begin the construction process. As we continue down the line, we employ various testing methods to ensure that each core performs optimally.

Assembled Core Electrical Testing: All assembled SLFM and DG cores are 100% tested on automated Yokogawa precision power analyzers to customer specifications guaranteeing that NLL (no load losses) are met.

Special Electrical Product Testing: Upon request, assembled SLFM and DG core can also be tested for insulation resistance and sound over a wide range of flux densities and frequencies. Detailed test reports and curve graphs may be provided.

More information on our sound testing capabilities can be found here.

First piece and PPAP inspection: Layout inspection and/or functional verification to customer engineered performance specification may be made available upon request.

Each and every core that we create has a special QR code that our customers can scan to see the results of each of these tests.


Corefficient maintains a 98% Ship-on-Time guarantee for our customers. From concept to delivery, we will have your core to you in two weeks or less.

The time is now. Contact Corefficient today and make your design dreams a reality!

Visit Corefficient online @ corefficientsrl.com, contact our North America Sales Engineer: 1(704) 236-2510 or call us directly in Monterrey, México: (81) 2088-4000.