Introduction to IEC Motors

March 22, 2023

In today's digitally connected world, online suppliers like eMotors Direct can bring global electric motor markets right to your doorstep. You now have a wider range of options to choose the motor that perfectly suits your application and budget.

When shopping for a new motor, you may come across IEC motors and wonder what they are and whether they can suit your application. Let's clarify what makes IEC motors unique and what they can offer you and your business.

What is an IEC Motor?

Simply put, an IEC motor is a motor manufactured according to European IEC standards, the European counterpart of the NEMA standards with which you may be more familiar. While NEMA standards apply in North America, IEC standards apply almost everywhere else. If you're shopping internationally, you're going to come across IEC motors often. These standards govern how information is presented and some design aspects.

As markets become more globalized and international regulation around energy efficiency increases, IEC standards have become increasingly infused with NEMA standards, making it vitally important to stay up-to-date. Companies that are flexible enough to choose from a wider selection of motors manufactured to a different international standard will have a competitive edge in minimizing costs.

IEC Standards

The IEC standards were created many decades ago to standardize the manufacture of electrical components and equipment throughout Europe, and the majority of countries have since adopted them. With electric motors identified as one of the primary consumers of energy worldwide, IEC's standards for electric motors have recently developed, focusing on energy efficiency. They also cover diverse aspects such as motor voltage, frame size, mounting type, hazardous area classification, and more.

The most common IEC standard you'll come across is IEC 60034, which classifies asynchronous AC squirrel-cage induction motors (the most popular type of motor worldwide) based on their efficiency. This standard is the driver in energy-efficiency legislation during the last decade, with the IE3 'Premium' classification now mandatory in many European countries for new motors up to 1000 kW.

Other key IEC standards include IEC 60038, which standardizes high- and low-voltage classifications for electric motors, and IEC 60072, which standardizes motor dimensions, mounting types, shaft characteristics, and maximum permissible torques based on shaft diameter.

If you need to familiarize yourself with these standards, we recommend consulting the relevant literature published by the IEC. But now you're probably wondering what exactly makes IEC motors different.

IEC Motor Design

IEC and NEMA motors of comparable ratings are typically very similar, but you need to be aware of a few fundamental differences.

One of IEC motors' main characteristics is that they do not include a service factor, unlike NEMA motors, which do have this rating. While the IEC concept of 'duty types' considers some aspects of service factor, you may need to derate an IEC motor if it's likely to experience intermittent spikes in the load and torque requirements.

All the dimensions of an IEC motor are in metric “mm” and are slightly different from NEMA motors which makes them impossible for a direct interchange. You could only look at using a NEMA motor in an IEC application if the critical dimensions could be changed or altered easily.

There are quite a few superficial characteristics that distinguish IEC motors. Still, these are the key differences that directly impact how well it will perform in your application.

When Should I Choose an IEC Motor?

Typically, when equipment comes over from Europe, it will have IEC motors and gear reducers with it. You would need to purchase IEC replacements in these scenarios or retrofit everything to NEMA products.

Finally, if your motor must conform to European standards in aspects such as energy efficiency or hazardous area classification, an IEC motor will make it far simpler to manage. This not only makes it easier for you to comply with regulations but also potentially take advantage of rebates for energy efficiency.


At eMotors Direct, we stock a vast range of both NEMA and IEC motors to bring you the best options for all your electric motor application requirements.

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