Knowing which of the dozens of motors in a facility comply with the current efficiency regulation is a critical question both for legal compliance and for energy cost. The answer to this question is often on the small metal label on the motor. Reading the motor efficiency label correctly and understanding the thresholds of the MEPS (Minimum Energy Performance Standards) regulation lets you clearly answer the question “which of my motors is compliant?”. In this article we address reading the IE class, kW, poles and efficiency information on the label, the MEPS/Ecodesign thresholds and the compliance check steps, and we explain how to make the decision to replace an old motor.

Reading IE class, kW, poles and efficiency on an electric motor efficiency label

What Information Is on the Motor Label?

The rated-values label (nameplate) fixed to the body of the electric motor is the most reliable source of information about the motor. To check efficiency compliance, you need to look at the following fields on this label:

  • Power (kW): the rated output power at the motor shaft. Because MEPS thresholds are defined by power range, this is the most critical value.
  • Speed (rpm) and poles: the speed indicates the number of poles. Approximately 2900 rpm = 2 poles, 1450 rpm = 4 poles, 950 rpm = 6 poles. MEPS defines some thresholds by pole.
  • Efficiency class (IE): IE1, IE2, IE3, IE4 or IE5. The IE class and the nominal efficiency percentage are usually written together on the label.
  • Efficiency percentage (%): the nominal efficiency at full load. Some labels also state the efficiency at 75% and 50% load.
  • Voltage, current and cosφ: the electrical connection and power factor information.

We addressed the topic of label reading generally in our Reading the IE3 Motor Nameplate: kW, Speed, Cosφ and Efficiency article, and pre-order nameplate matching in our Avoid Receiving the Wrong Motor article.

How Is the IE Class Read?

The IE (International Efficiency) class is defined according to the IEC 60034-30-1 standard and shows the motor’s efficiency level. The order from low to high is IE1 (Standard), IE2 (High), IE3 (Premium), IE4 (Super Premium) and IE5 (Ultra Premium). At the same kW and speed, as the IE class rises the motor’s efficiency increases and its losses decrease. You can examine IE5 and the synchronous reluctance structure in our IE5 and Synchronous Reluctance Motors article.

MEPS and Ecodesign Regulation: What Are the Thresholds?

MEPS (Minimum Energy Performance Standards) are regulations that require motors in a certain power and pole range to meet a minimum efficiency class. In the European Union this framework is implemented through the Ecodesign Regulation (2019/1781), and in Türkiye through the relevant communiqués. The general thresholds can be summarised as follows:

  • From 1 July 2021: at least IE3 is mandatory for three-phase single-speed motors in the 0.75–1000 kW range, 2/4/6/8 poles, running directly on line (DOL).
  • In the 0.12–0.75 kW range: at least IE2 is required.
  • From 1 July 2023: at least IE4 became mandatory for 2/4/6 pole motors in the 75–200 kW range.
  • From 1 July 2023: the requirement of at least IE2 was also introduced for single-phase motors above 0.12 kW.

These thresholds form the basis of the question “which of my motors is compliant?”. We detailed the date and power distribution of the efficiency mandate in our IE3 and IE4 Efficiency Mandate article, and which class is required at which power in our IE3 Efficiency Class Mandate article. We addressed the IE4 threshold in pumps, fans and compressors in our The IE4 Threshold in Pumps, Fans and Compressors article.

Motor compliance check steps according to MEPS efficiency thresholds

Compliance Check: Step by Step

To check whether a motor complies with the regulation, follow these steps:

  1. Read the power: note the kW value on the label. Thresholds are defined by power range.
  2. Determine the poles: derive the number of poles from the speed (e.g. 1450 rpm = 4 poles).
  3. Check the phase and operating mode: three-phase or single-phase, direct on line or drive-based?
  4. Read the IE class: find the IE marking on the label.
  5. Compare with the threshold: does it meet the minimum IE class corresponding to its power?

For example, a 4-pole, 11 kW, three-phase, DOL-running motor must be at least IE3; if its label says IE2, this motor is behind the current regulation. To do this check systematically across the facility, the inventory approach in our Preparing for an Energy Efficiency Audit: Motor Inventory article is very useful. You can find prioritisation within the ISO 50001 framework in our ISO 50001 and Motor Efficiency article.

The Difference Between Nameplate and Field Efficiency

The efficiency on the label is the nominal value under standard test conditions; the real efficiency in the field can vary according to the load ratio and operating conditions. To calculate the real savings correctly, see our The Difference Between Nameplate and Field Efficiency article, and for the correct load ratio our At What Load Should a Motor Run? article.

The Old Motor Replacement Decision

When you come across a motor whose label says IE1 or IE2 and which falls behind the current threshold, the replacement decision should be evaluated from two angles:

  • Legal compliance: when buying a new motor, you should choose a class that meets the current MEPS threshold. Sales restrictions on IE2 motors directly affect this decision.
  • Economic justification: for a motor with high running hours, raising the efficiency class can pay for itself through energy savings. We addressed this in our IE3 or IE4? The Right Investment and Move to IE4 or Stay With IE3? articles.

We examined the question of rewinding an old motor versus buying a new one in our Rewind a Motor or Buy New? article, and the question of whether old-stock IE2 makes sense in our The Difference Between IE3 and IE2 Motors article. To verify mechanical compatibility during replacement, our Mechanical Compatibility When Moving to IE4 and Direct Replacement of an Old Brand Motor articles guide you. You can also find the TCO logic in our Total Cost of Ownership (TCO) article.

Deriving the Pole Count From Speed: A Practical Method

Because MEPS thresholds are in some cases defined by the number of poles, it is important to derive the pole count correctly from the speed value on the label. On a 50 Hz grid the synchronous speeds and corresponding pole counts are as follows:

  • 2 poles: 3000 rpm synchronous, usually about 2900-2960 rpm on the label.
  • 4 poles: 1500 rpm synchronous, about 1440-1470 rpm on the label.
  • 6 poles: 1000 rpm synchronous, about 960-980 rpm on the label.
  • 8 poles: 750 rpm synchronous, about 720-740 rpm on the label.

The speed on the label is slightly lower than the synchronous speed; this difference arises from the slip of the asynchronous motor. We explained the slip and actual-speed relationship in our Slip and Actual Speed in Asynchronous Motors article. You can examine the effect of pole selection on the application in our Asynchronous Motor Buying Guide: 2, 4, 6 Poles article.

Other Information on the Label and Its Importance for Ordering

Beyond efficiency compliance, the label carries vital information for ordering and replacement. To avoid receiving the wrong motor and to replace an existing motor exactly, the following fields should also be recorded:

  • Frame size: determines the mounting dimensions in the IEC 56-355 range.
  • Mounting type: B3 foot-mounted, B5/B14 flange, B35 combined. We addressed the connection type in our B5 or B14? article.
  • Protection class (IP): such as IP55, IP65. We examined selection by environment in our IP Protection Class Selection in Electric Motors article.
  • Insulation and duty type: F/H insulation and S1-S6 duty type. We addressed the duty type in our Duty Type (S1-S6) Selection article.
  • Service factor (SF): indicates overload capacity; you can look at our Service Factor in IE3 Motors article.

Providing this information in full when requesting a quote lets you get an accurate and fast price; we compiled this in our 8 Pieces of Information Required When Requesting an Electric Motor Quote article.

Facility-Wide Compliance Audit

Checking a single motor is easy; however, auditing compliance systematically in a facility with hundreds of motors requires planning. First, an inventory containing the nameplate information of all motors is drawn up; then each motor is marked against the relevant threshold with the power-pole-IE class trio. Motors that fall behind the threshold and at the same time have high running hours are prioritised for replacement.

We addressed this inventory work in our Preparing for an Energy Efficiency Audit: Motor Inventory article and investment prioritisation in our ISO 50001 and Motor Efficiency article. You can find motor fleet management in facilities running three shifts in our Motor Fleet Management in Three-Shift Facilities article. You can get support for compliant motor replacement through our HEM Motor product range home page and our contact channels.

Frequently Asked Questions

If the label is unreadable, how do I find the motor’s efficiency class?

If the label is worn or unreadable, an equivalent model is attempted to be determined from the motor’s power, speed, frame size and production information; however, the efficiency class can only be confirmed for certain from the label or the manufacturer’s documentation. In this case, getting expert support to determine the correct class through measurement and equivalent-model work is the safest way. When trying to identify the power without a label, the frame size and speed give important clues.

I have an IE2 motor, do I have to replace it immediately?

It is generally possible to continue using an existing, working motor; the regulations mainly cover motors newly placed on the market. However, when making a new purchase you must choose a class that meets the current MEPS threshold. For an IE2 motor with high running hours, early replacement can also make economic sense because of the energy savings.

Does every motor above 75 kW have to be IE4?

From 1 July 2023, at least IE4 became mandatory for 2/4/6 pole motors in the 75–200 kW range. The threshold can differ for powers outside this range and under different conditions; therefore you should check the motor’s exact kW, poles and operating mode and compare them with the relevant threshold.

Get a Quote

If you want to determine whether the motors in your facility comply with the current efficiency regulation and to plan their replacement with compliant new motors, our team will examine your inventory and determine the right efficiency class together with you. Contact us now at +90 (532) 345 49 86 or request a quote via our contact page.

Efficiency Label and MEPS Compliance Checklist

  • Read the motor’s kW value from the label.
  • Determine the number of poles from the speed (2/4/6/8).
  • Check the phase type (single-phase/three-phase) and operating mode (DOL/drive-based).
  • Note the IE class and efficiency percentage on the label.
  • Determine the minimum MEPS threshold corresponding to its power.
  • Compare the IE class on the label with the threshold.
  • Mark the motors behind the threshold in your inventory.
  • Give replacement priority to motors with high running hours.
  • For new purchases, choose a class that meets the current threshold.
  • During replacement, verify the mechanical (frame/shaft/flange) and electrical compatibility.