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Knowledge Center

IEC-standard motors

Questions about technology? Here are the solutions!

What are IEC electric motors?

Version: 01.10.2024

In our knowledge database you will find comprehensive explanations of the technical principles, possible applications and advantages of these standardised motors.

Discover valuable expertise, practical instructions and detailed FAQs about IEC electric motors.

If you have any questions that go beyond the FAQs or require specific support, our team of experts will be happy to help you at any time.

What are IEC electric motors?

IEC standard motors: Standardised electric motors for worldwide use

IEC electric motors, often referred to as standard motors, are electrical drives standardized according to the specifications of the International Electrotechnical Commission (IEC). This international organization sets globally recognized standards for the electrical and electrotechnical industry, aiming to ensure the compatibility, safety, and performance of devices. The IEC standards for electric motors cover a wide range of technical parameters, including performance characteristics, frame sizes, efficiency classes, and mechanical dimensions. Thanks to this standardization, IEC standard motors can be used in various countries and regions without adaptation to local conditions, facilitating the global integration of industrial systems.

FAQs - Frequently asked questions

Questions about standard motors

We know that many questions can arise when using electric motors. Our goal is to provide you with the knowledge and tools you need to implement your projects efficiently and successfully. That’s why we have compiled the most frequently asked questions and answered them in our knowledge base.

General questions

The International Electrotechnical Commission (IEC) has established globally recognized standards for the efficiency classes of electric motors. These standards were introduced in 1999 by the European Commission to reduce energy consumption and raise awareness of sustainable environmental practices across various industries. Originally known as EFF standards, these efficiency classes were later replaced by the current IEC standards to eliminate international inconsistencies. In contrast, the United States developed the NEMA standards, which differ significantly from the European norms. The shift to IEC standards has helped create uniform regulations for electric motors worldwide.

IEC standard motors meet the international standards set by the International Electrotechnical Commission (IEC). These standards define precise requirements for the design, performance, and safety of electric motors. Thanks to this standardization, IEC motors are globally compatible and meet consistent quality standards, greatly simplifying international trade and use in various markets.

They offer high flexibility, whether in selecting the appropriate motor or replacing faulty units. Standardizations such as the IEC standards also contribute to ensuring the energy efficiency and safety of the motors.

Conversion of electrical energy into mechanical energy

IEC electric motors are typically alternating current (AC) motors that convert electrical energy into mechanical energy. The basic operating mechanism is based on the interaction between a rotating magnetic field in the stator and a rotor that is set in motion. The motor converts the electric current flowing through the stator into rotational motion, which is then used to drive machines or devices. Depending on the design and application, they can be constructed as induction or synchronous motors.

IEC standard motors are classified according to protection types, which indicate the degree of protection against the ingress of solids and liquids. These protection types, as per the IEC 60529 standard, are identified by IP codes such as IP55. A motor with an IP55 protection rating is protected against harmful dust deposits and water jets from all directions, which expands its applications in various environments and enhances operational safety.

The selection of the optimal motor depends on various factors: power requirements, load profiles, environmental influences, and specific requirements for efficiency or safety regulations. In our knowledge base, you will find step-by-step guides for choosing the right electric motor, including key criteria such as rated power, torque, speed, and insulation class. Additionally, we provide tips on how to avoid mistakes in selection and improve the efficiency of your systems.

The IEC standards define clear requirements for the electrical and mechanical performance of electric motors. These include protection types (IP protection classes), resistance to environmental influences (such as moisture, dust, or extreme temperatures), insulation classes, efficiency classes, and noise levels. Our knowledge base provides detailed information on these classifications and explains how to correctly interpret and apply the various standards to your applications.

IEC electric motors are known for their high interchangeability and international availability. They are ideal for applications where machines or systems are used in different countries. Thanks to the worldwide availability of spare parts and motors, as well as standardized connection and installation guidelines, they minimize downtime and maintenance costs. Our knowledge base explains the key benefits and provides valuable tips on how to make the right decisions for your projects.

Regular maintenance is key to ensuring a long lifespan and optimal performance of electric motors. In our knowledge base, we provide a detailed overview of the necessary maintenance measures. These include inspecting bearings, checking electrical connections, measuring insulation resistance, and proper lubrication. Additionally, you will find troubleshooting guides for common issues such as overheating, bearing damage, or voltage drop.

Choosing a highly efficient motor can significantly reduce energy consumption and lower operating costs in the long term. In our knowledge base, you will learn about measures that contribute to improving energy efficiency. These include the use of frequency converters, selecting the right motor size, and performing regular inspections and maintenance. We also explain the various efficiency classes, such as IE1, IE2, IE3, and IE4, and provide recommendations on how to optimize their use in your company.

Important standards in comparison

Since 2021, electric motors with a power rating of 0.75 kW or higher must meet the energy efficiency class IE3. The combination of IE2 motors and a VSD (Variable Speed Drive) configuration is no longer allowed. For motors in the power range of 0.12 kW to 0.55 kW, the requirement to achieve at least the energy efficiency class IE2 has been in effect since 2021. Motors with brushes, commutators, slip rings, or other electrical connections to the rotor, often referred to as pole-switchable motors, are exempt from these regulations.

The choice of the right energy efficiency class depends on the specific requirements of your application. Higher efficiency classes generally result in higher initial costs but offer greater long-term savings on operating costs and help reduce environmental impact.

IE1 - Standard Efficiency

IE1 stands for standard efficiency. These motors offer a basic energy standard and are suitable for applications where efficiency is not the highest priority.

  • Power class: Less than or equal to 0.09 kW

IE2 - High Efficiency

IE2 refers to high-performance motors that offer improved energy efficiency compared to IE1. These motors further reduce energy consumption and operating costs.

  • Power class: Motors with a power rating of 0.12 kW to 0.55 kW must meet at least the IE2 efficiency class starting in 2021.
  • Special condition: Electric motors that do not meet the IE2 efficiency class may only be supplied as spare parts, provided the delivery date is before 2021.

IE3 - Premium Efficiency

IE3 stands for premium efficiency. These motors offer even higher efficiency than IE2 and make a significant contribution to reducing energy consumption.

  • Power classes: IE3 includes motors with outputs from 0.75 to 1,000 kW.
  • Area of application: Recommended for modern applications and systems that strive for maximum energy efficiency and cost savings.

IE4 - Super Premium Efficiency

IE4 denotes super-premium efficiency. These motors achieve the highest available efficiency level and are designed to minimise energy consumption and operating costs.

  • Power classes: IE4 includes motors with outputs from 0.75 to 1,000 kW.
  • Area of application: Ideal for applications where maximum energy savings are required and the operating requirements are particularly high.

IE5 - Ultra Premium Efficiency

IE5 is the latest and most advanced energy efficiency class, offering even higher efficiency than IE4. These motors use advanced technologies to optimise energy utilisation.

  • Power classes: IE5 currently mainly comprises motors with outputs from 0.12 to 200 kW.
  • Area of application: Ideally suited for specialised applications that require maximum efficiency and minimum energy consumption.

The Low Voltage Directive (2014/35/EU) specifies safety requirements for electrical equipment operating in the voltage range from 50 to 1000 V (AC voltage). This applies to practically all industrial motors that fall within the power range of the IEC standard.

The Low Voltage Directive (2006/95/EC or, since 2016, 2014/35/EU) serves to protect people, animals and property from electrical hazards that can be caused by electrical devices and systems. It applies to electrical equipment that is operated with a rated voltage of 50 to 1,000 volts alternating current (AC) or 75 to 1,500 volts direct current (DC).

The Low Voltage Directive does not directly affect energy efficiency requirements but ensures that motors are operated safely and reliably. On the other hand, the energy efficiency classes (IE1 to IE5) according to the IEC standard focus on the aspect of energy savings.

Basic Importance: The directive ensures that electrical products sold in the EU meet specific safety requirements to guarantee safe usage. Manufacturers, importers, and retailers must ensure that their products comply with the fundamental safety requirements of the directive and bear the CE marking, which confirms conformity. Compliance with the Low Voltage Directive is essential for the free movement of goods within the European Single Market and protects end consumers as well as operators of electrical installations from hazards caused by faulty or unsafe devices.
IEC standard motors follow the European IEC standards, while NEMA motors comply with the North American standards of the National Electrical Manufacturers Association (NEMA). The main differences lie in the dimensions and technical specifications.

The Ecodesign Directive (2009/125/EC), also known as the ErP Directive (Energy-related Products), is a European regulation that defines minimum requirements for the environmentally friendly design of energy-related products. The aim of this directive is to reduce the energy consumption and environmental impact of products throughout their entire life cycle. This directive is particularly relevant for electric motors, as they are widely used in many industrial applications and account for a significant proportion of global energy consumption.

Scope of the Ecodesign Directive

Regulation (EU) 2019/1781 implementing the Ecodesign Directive came into force on July 1, 2021 and regulates the energy efficiency requirements for electric motors and frequency inverters in the EU. This regulation replaces the former Regulation (EU) No. 640/2009 and sets stricter requirements for the energy efficiency of electric motors.

The requirements mainly concern:

  • Three-phase asynchronous motors (also known as induction motors), which are most commonly used in industry.
  • Frequency inverters used to control and optimise the speed of motors.

The Ecodesign Directive requires different minimum standards in terms of energy efficiency depending on the motor class. The most important requirements are:

1. requirements from 1 July 2021:

  • Motors with an output of 0.75 kW to 1,000 kW must comply with efficiency class IE3 (Premium Efficiency) as a minimum.
  • Motors with an output of between 75 kW and 200 kW that work under certain operating conditions must even achieve IE4 (Super Premium Efficiency).
  • Variable frequency drives (VFDs) must also fulfil certain efficiency requirements, as they play a central role in saving energy in variable drive systems.

2. requirements from 1 July 2023:

  • Motors with a power rating between 75 W and 200 kW, which are used as "invisible energy consumers" in many smaller applications, must meet at least the IE4 efficiency class (Super Premium Efficiency).
  • Explosion-proof motors and motors that operate in extreme environments are now also subject to efficiency requirements and must achieve IE3 in most cases.
  • Embedded motors, such as those found in ventilation systems or pump systems, are also subject to stricter regulations in order to minimise energy losses.

3. specific requirements:

  • Single-phase motors: Single-phase motors with a power rating of 0.12 kW to 0.75 kW must meet at least the IE2 efficiency class starting from July 2021.
  • Electric motors with a power rating above 0.75 kW must meet the IE3 efficiency class. Single-phase motors with a power rating above 0.75 kW are rare, as they are typically used for lower power ratings (under 1 kW), and most motors in higher power classes are three-phase.

Exceptions and special features

The regulation contains some exceptions for certain types of engines or applications:

  • Motors with an integrated brake or motors for special environments, e.g. in potentially explosive atmospheres or extreme temperatures, have special exceptions.
  • Special motors such as high-speed motors or water cooling systems are exempt from the strict efficiency requirements in certain cases.

Exceptions and special features

Ban on less efficient motors

With the entry into force of the Ecodesign Directive, motors below the IE3 efficiency class (with some exceptions) can no longer be sold or placed on the market in the EU. This forces manufacturers of electric motors to shift their production to more efficient models.

Long-term energy savings

The introduction of motors with a higher efficiency class leads to significant energy savings in the industry. This contributes to achieving climate targets and reduces operating costs in the long term.

Market changes

Both the market for high-performance electric motors and frequency inverters have been strongly influenced by the new requirements of the directive. More and more companies are having to switch to more efficient technologies.

Costs and investments

Although motors with higher efficiency classes are more expensive to purchase, the additional costs are amortised over the course of operation due to the energy savings. The higher initial investment is offset by long-term savings in operating costs.

Effects

The Ecodesign Directive is a key instrument for reducing energy consumption in Europe and contributing to climate protection. The new minimum energy efficiency requirements for electric motors promote the use of more energy-efficient devices and reduce operating costs for companies in the long term. In addition, the market will be guided towards a higher standard that promotes the use of modern technologies and solutions in the industry.

The IM code

IM-Code:

The IM code (International Motor Code) is a standardised identification system developed by the International Electrotechnical Commission (IEC) to describe the design and equipment of electric motors. The IM code enables simple identification of the motor design and the associated protection class. It helps to correctly select the motor for the intended place of use and the specific requirements.

The code includes

  • Position of the motor shaft
  • Type of end shields
  • Fastening the machine
  • Installation type
  • Design of the shaft end

The IM code is crucial to ensure that the electric motor fulfils the specific requirements of its application. It simplifies the selection of the right motor for different environmental conditions and applications, minimises the risk of incorrect purchases and contributes to the operational reliability and longevity of the motors.

The IM code consists of a combination of letters and numbers that describe various aspects of the engine, including

  • Motor design/type
  • Shaft configuration
  • Mounting and installation type

Structure of the IM-Code

The IM code consists of a number and one or more letters that specify the following characteristics of the motor:

  • First number: Indicates the motor design and the shaft configuration.
  • Letter(s): Indicate the mounting type of the motor, such as foot mounting or a special arrangement.

Example of an IM code and its meaning:

Marking according to DIN EN 60034-7

Code 1 and Code 2: These are standardized descriptive codes derived from the IM coding system, representing a combination of the shaft position and the mounting type of a motor.

The difference between codes like IMB3 and IM1001 lies in the specific characteristics of the motor, which relate to the shaft configuration and mounting type.

Example according to the standard: Design IMB3 / IM1001

Meaning of Code 1: IMB3

  • I: Refers to the motor design and indicates that it is a standard electric motor.
  • M: Refers to the motor shaft, which in this case is horizontal.
  • B3: Indicates the mounting type – in this case, it is foot mounting (i.e., the motor is mounted on a base or a pedestal).

Meaning of Code 2: IM1001

  • 1: Code 1 refers to the position of the shaft, such as horizontal or vertical.
  • 00: In this case, this code often describes a specific installation type.
  • 1: Additional features (for example, a special motor design or arrangement).

The design of an electric motor, as specified in the IM code, describes the physical construction and the way the motor is built and mounted. This information is crucial for selecting the motor in terms of installation, degree of protection, and operating environment.

Basic designs of IEC electric motors

IM B3

Foot version

IM B35

Flange version with through holes and feet

IM B5

Flange with through holes

IM B14

Flange with threaded holes

IM B34

Flange version with threaded holes and feet

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