Midwest Current Transformer has been an industry leader in design and production of current transformer products for over 50 years. Our focus is to build quality products designed to meet your needs. You may choose from any of our standard products or we can design and build a custom solution specifically for your application.

Superior Goals and Higher Expectations

It is the goal of Midwest Current Transformer to maintain its position as a worldwide industry leader . . .

Click here to learn more.

Worldwide Leader

American Pride Made  in  the  U.S.A.

CT Series Current Transformer

CT Series Current Transformer

The CT Series offers a wide range of standard ratios to 1 amp and 5 amp secondary outputs.

Standard units are manufactured with 24 inch leads, 600 volt fiberglass insulation wrap and a protective polyurethane coating.

Screw terminals, high voltage insulation, mounting brackets and ratios to 0.1 amp are available. Please specify when placing your order.

RC Series Current Transformer

RC Series Current Transformer

The RC Series offers a wide range of standard ratios to 1 amp and 5 amp secondary outputs.

Standard units are manufactured with 24 inch leads and a round polycarbonate case.

Mounting brackets and ratios to 0.1 amp are available. Please specify when placing your order.

SC Series Current Transformer

SC Series Current Transformer

The SC Series offers a wide range of standard ratios to 1 amp and 5 amp secondary outputs.

Standard units are manufactured with brass screw terminals and a square polycarbonate case.

Lead wires instead of screw terminals and ratios to 0.1 amp are available. Please specify when placing your order.

Custom Current Transformer

Custom Current Transformer

Midwest Current Transformer offers you a wide range of current transformers. Should a standard unit not meet your specific application, our experienced staff will design a custom current transformer for you.

Online Catalog

Search Our Catalog

Find existing products for your current transformer needs.

Quote Cart

View items you have added to your quote cart.

Compare Items

Compare items before adding them to your quote cart.

Premier Current Transformer Manufacturing Company

As a premier leader among current transformer suppliers, Midwest Current Transformer has served customers requiring high quality current transformer products for more than five decades. Our targeted focus is the manufacture of standard and custom design current transformer solutions to meet the requirements of a wide range of applications.

Customized Current Transformer Design

We offer pre-made current transformers to serve the needs of various power applications. Our team is able to customize your order in order to help you achieve the optimum current transformer solution in terms of size, ratio, accuracy, multiple taps, contacts, mounting options, and burden rating.

Our Electrical Current Transformer Construction

At Midwest Current Transformer, we manufacture the majority of our current transformers from cold-rolled grain oriented electrical steel (CRGO). The CRGO steel comprising our current transformers is rolled into your required inner and outer diameter dimensions which permits precise dimensioning and tight construction between layers. As an iron-silicon alloy, CRGO electrical steel provides high permeability and low core loss that enables greater efficiency and cost-effectiveness of the current transformer.

Total Quality Management

Our approach consists of Total Quality Management protocol in which our employees, customers, and suppliers are valued as an integral part of our successful process. Our standard for success is error-free performance with the commitment to error prevention and getting-the-job-done-right-the-first-time mindset.

Through hands-on product inspection as part of an entire quality management system, we strive for perfection at every stage of the manufacturing process before your products leave our hands. We push toward continual quality improvement, adherence to safety standards, and personnel development through high-value training across all levels of our operations.

Contact Us

For more information about the superior current transformer products we offer at Midwest Current Transformer, call us today at 800.893.4047 or email sales@aenpi.com.

2 minutes reading time (300 words)

Removing the Mystery from Current Transformer Classes

Current transformers are an important part of power transmission and control panel applications today. They have many ratings, and some can be customized to your business. However, there are letters and numbers printed on current transformers, and it is important to know what they mean. This brief explanation can help you get a better understanding of the subject.


The difference between secondary (Is) and primary (Ip) currents is the ratio. For instance, when you order your current transformers from Midwest Current Transformer, you have to specify the amps for primary current rating. Secondary current ratings are either 1 or 5 amps. 5 amp CT applications are common. However, when circuit relays are at a distance, 1 amp CT applications are best because of factors like voltage drop.


CTs are rated by accuracy class. It is very important because there is potential for error between the primary and secondary currents. Accuracy is dependent upon: 

  • Saturation – this is the point where a core is completely magnetized and producing the most flux.

  • Burden – load of the secondary side of the transformer

  • Load – equipment connected to circuit and drawing current. It can vary a great deal, but there is a maximum the CT can safely handle.

  • Frequency

  • Temperature


Suppose you have a CT class 5p20 current transformer. The first number represents how accurate it is. Most transformers are between five and ten. The letter “P” stands for protective device. It is meant to prevent overcurrent conditions to protect circuits and equipment. The next number, “20” is the accuracy factor. For example, the 5p20 CT can do its job even when there is 20 times the current flowing in the secondary.

If you are unsure of your CT needs, call Midwest Current Transformer today. Our toll-free number is 1-800-893-4047.

Metering Vs. Protective Current Transformers
Common Applications for Current Transformers