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Line Operated AC Motors

1.1    Scope

Line operated AC motors are used to drive plant and machinery throughout industry and commerce, and a wide range of ‘general purpose’ products are available in internationally agreed, standard designs with different rated power outputs, frame sizes, fixed operating speeds, and energy efficiency ratings.

The Energy Technology List (ETL) aims to encourage the purchase of higher efficiency three-phase line operated AC motors ranging between 0.12 kW and 1,000 kW, and single phase line operated AC motors ranging from 0.12 kW upwards.

To be eligible for inclusion on the ETL, products shall meet the requirements as set out below. 

1.2    Definitions

Line operated ac motors covers products that are specifically designed to convert standard single and three phase electrical power into mechanical power, and to rotate a drive shaft at a fixed speed that is directly related to the frequency of the electrical power supply. 

  • Single-phase motors: rotating electrical machines driven by a single phase alternating current, in which all the supplied voltage changes simultaneously. 
  • Three-phase motors: rotating electrical machine driven by three single-phase alternating currents of equal frequency and amplitude, with a 120-degree phase difference.
  • Ex-eb increased safety motors: motors providing a higher level of protection required under the atmosphere explosives (ATEX) Directive 2014/34/EU. These motors ensure reliable prevention of abnormally high temperatures, sparks or electrical arcs, of the motor’s electrical equipment.

1.3    Requirements 

1.3.1    Eligibility requirements  

To be eligible both single and three-phase motors shall:

  • Be a totally enclosed AC motor that has:
      a)    A maximum rated operating voltage above 50 V up to 1,000 V 
      b)    2, 4, 6 or 8 poles.
      c)    A built-in method of cooling that is classified according to BS EN 60034-6:1994, “Rotating electrical machines. Methods of cooling (IC Code) as:
      –    IC 410: (frame surface cooled – free convection),
      –    IC 411: (frame surface cooled – self circulation)
      –    IC 418: (frame surface cooled circulation by relative displacement.)
      d)    Dimensions and a power rating that conform with the requirements of IEC 60072-1: 1991-02 (sixth edition), “Dimensions and output series for rotating electrical machines – Part 1: Frame numbers 56 to 400 and flange numbers 55 to 1080”.
  • Be capable of direct connection to the UK public electricity supply system, or a private alternating current supply of nominally fixed frequency and voltage
  • Be rated at 50 Hz in accordance BS EN 60034-1:2010 (or IEC 60034-1: 2010) “Rotating electrical machines - Part 1: Rating and performance”.
  • Have a ‘Duty type S1 – Continuous running duty’ rated power output that is greater than or equal to 0.12 kW and, in the case of three-phase line operated AC motors, less than or equal to 1000 kW as defined in Section 4.2.1 of BS EN 60034-1: 2010.
  • Be CE Marked. 

1.3.2    Performance requirements 

1.3.2.1    Tier 1 – From September 2020

Products shall have an efficiency when tested in accordance with BS EN 60034-2-1: 2014 at full load (i.e. 100% of their maximum continuous rated power output) that is greater than or equal to the values shown in Table 1.1 below, which vary with the rated power output, safety classification and the number of poles.

If the product’s specific rated power output is not shown in Table 1.1, then the performance threshold is determined by interpolation in accordance with the method set out in Section 5.4.5 of BS EN 60034-30-1: 2014. 

Until further notice results of tests according to BS EN 60034-2-1:2007 for products listed before September 2020 will also be accepted.

Efficiencies at full load for Ex-eb increased safety motors can be found in Table 1.1 (b), which vary with the rated power and the number of poles.  

Table 1.1    Performance thresholds for three-phase line operated AC motors from 0.12 kW to 1000 kW.

Rated Power Output (kW) Efficiency at full load (%)
2 Pole 4 Pole 6 Pole 8 Pole
0.12 ≥ 60.8 ≥ 64.8 ≥ 57.7 ≥ 50.7
0.18 ≥ 65.9 ≥ 69.9 ≥ 63.9 ≥ 58.7
0.2 ≥ 67.2 ≥ 71.1 ≥ 65.4 ≥ 60.6
0.25 ≥ 69.7 ≥ 73.5 ≥ 68.6 ≥ 64.1
0.37 ≥ 73.8 ≥ 77.3 ≥ 73.5 ≥ 69.3
0.4 ≥ 74.6 ≥ 78.0 ≥ 74.4 ≥ 70.1
0.55 ≥ 77.8 ≥ 80.8 ≥ 77.2 ≥ 73.0
0.75 ≥ 83.5 ≥ 85.7 ≥ 82.7 ≥78.4
1.1 ≥ 85.2 ≥ 87.2 ≥ 84.5 ≥80.8
1.5 ≥ 86.5 ≥ 88.2 ≥ 85.9 ≥82.6
2.2 ≥ 88.0 ≥ 89.5 ≥ 87.4 ≥84.5
3 ≥ 89.1 ≥ 90.4 ≥ 88.6 ≥85.9
4 ≥ 90.0 ≥ 91.1 ≥ 89.5 ≥87.1
5.5 ≥ 90.9 ≥ 91.9 ≥ 90.5 ≥88.3
7.5 ≥91.7 ≥92.6 ≥91.3 ≥89.3
11 ≥92.6 ≥93.3 ≥92.3 ≥90.4
15 ≥93.3 ≥93.9 ≥92.9 ≥91.2
18.5 ≥93.7 ≥94.2 ≥93.4 ≥91.7
22 ≥94.0 ≥94.5 ≥93.7 ≥92.1
30 ≥94.5 ≥94.9 ≥94.2 ≥92.7
37 ≥94.8 ≥95.2 ≥94.5 ≥93.1
45 ≥95.0 ≥95.4 ≥94.8 ≥93.4
55 ≥95.3 ≥95.7 ≥95.1 ≥93.7
75 ≥95.6 ≥96.0 ≥95.4 ≥94.2
90 ≥95.8 ≥96.1 ≥95.6 ≥94.4
110 ≥96.0 ≥96.3 ≥95.8 ≥94.7
132 ≥96.2 ≥96.4 ≥96.0 ≥94.9
160 ≥96.3 ≥96.6 ≥96.2 ≥95.1
200 ≥96.5 ≥96.7 ≥96.3 ≥95.4
250 up to 1000 ≥96.5 ≥96.7 ≥96.5 ≥95.4


Table 1.1 (b)    Performance thresholds for three-phase line operated AC motors from 0.12 kW to 1000 kW. Ex-eb increased safety motors only.
 

Rated Power Output (kW) Efficiency at full load (%)
2 Pole 4 Pole 6 Pole 8 Pole
0.12 ≥ 53.6 ≥ 59.1 ≥ 59.1 ≥ 39.8
0.18 ≥ 60.4 ≥ 64.7 ≥ 64.7 ≥ 45.9
0.2 ≥ 61.9 ≥ 65.9 ≥ 65.9 ≥ 47.4
0.25 ≥ 64.8 ≥ 68.5 ≥ 68.5 ≥ 50.6
0.37 ≥ 69.5 ≥ 72.7 ≥ 72.7 ≥ 56.1
0.4 ≥ 70.4 ≥ 73.5 ≥ 73.5 ≥ 57.2
0.55 ≥ 74.1 ≥ 77.1 ≥ 77.1 ≥ 61.7
0.75 ≥ 77.4 ≥ 79.6 ≥ 78.9 ≥ 66.2
1.1 ≥ 79.6 ≥ 81.4 ≥ 81.0 ≥ 70.8
1.5 ≥ 81.3 ≥ 82.8 ≥ 82.5 ≥ 74.1
2.2 ≥ 83.2 ≥ 84.3 ≥ 84.3 ≥ 77.6
3 ≥ 84.6 ≥ 85.5 ≥ 85.5 ≥ 80.0
4 ≥ 85.8 ≥ 86.6 ≥ 86.6 ≥ 81.9
5.5 ≥ 87.0 ≥ 87.7 ≥ 87.7 ≥ 83.8
7.5 ≥ 88.1 ≥ 88.7 ≥ 88.7 ≥ 85.3
11 ≥ 89.4 ≥ 89.8 ≥ 89.8 ≥ 86.9
15 ≥ 90.3 ≥ 90.6 ≥ 90.6 ≥ 88.0
18.5 ≥ 90.9 ≥ 91.2 ≥ 91.2 ≥ 88.6
22 ≥ 91.3 ≥ 91.6 ≥ 91.6 ≥ 89.1
30 ≥ 92.0 ≥ 92.3 ≥ 92.3 ≥ 89.8
37 ≥ 92.5 ≥ 92.7 ≥ 92.7 ≥ 90.3
45 ≥ 92.9 ≥ 93.1 ≥ 93.1 ≥ 90.7
55 ≥ 93.2 ≥ 93.5 ≥ 93.5 ≥ 91.0
75 ≥ 93.8 ≥ 94.0 ≥ 94.0 ≥ 91.6
90 ≥ 94.1 ≥ 94.2 ≥ 94.2 ≥ 91.9
110 ≥ 94.3 ≥ 94.5 ≥ 94.5 ≥ 92.3
132 ≥ 94.6 ≥ 94.7 ≥ 94.7 ≥ 92.6
160 ≥ 94.8 ≥ 94.9 ≥ 94.9 ≥ 93.0
200 ≥ 95.0 ≥ 95.1 ≥ 95.1 ≥ 93.5
250 up to 1000 ≥ 95.0 ≥ 95.1 ≥ 95.1 ≥ 93.5

 

1.3.2.2    Tier 2 – From April 2023

Products shall have an efficiency, when tested in accordance with BS EN 60034-2-1: 2014 at full load (i.e. 100% of their maximum continuous rated power output), that is greater than or equal to the values shown in tables below, which vary with the rated power output, safety classification and the number of poles. If the product’s specific rated power output is not shown in these tables, then the performance threshold is determined by interpolation in accordance with the method set out in Section 5.4.5 of BS EN 60034-30-1: 2014. 

Until further notice results of tests according to BS EN 60034-2-1:2007 for products listed before September 2020 will also be accepted.

The requirements under Tier 1 will remain the same from April 2023 apart from under the following circumstances:

  • Efficiency thresholds for Ex-eb increased safety motors will be increased as indicated in Table 1.2.
  • Efficiency thresholds for power sizes equal to or greater than 75 kW and equal to or lower than 200 kW will be increased as indicated in Table 1.3.
  • Single phase motors ≥0.12 kW will be in scope, with a minimum efficiency at full load that is greater than or equal to the values shown in Table 1.4.

 
Table 1.2    Tier 2 performance thresholds for Ex-eb increased safety motors.

Rated Power Output (kW) Efficiency at full load (%)
2 Pole 4 Pole 6 Pole 8 Pole
0.12 ≥ 60.8 ≥ 64.8 ≥ 57.7 ≥ 50.7
0.18 ≥ 65.9 ≥ 69.9 ≥ 63.9 ≥ 58.7
0.2 ≥ 67.2 ≥ 71.1 ≥ 65.4 ≥ 60.6
0.25 ≥ 69.7 ≥ 73.5 ≥ 68.6 ≥ 64.1
0.37 ≥ 73.8 ≥ 77.3 ≥ 73.5 ≥ 69.3
0.4 ≥ 74.6 ≥ 78.0 ≥ 74.4 ≥ 70.1
0.55 ≥ 77.8 ≥ 80.8 ≥ 77.2 ≥ 73.0
0.75 ≥ 80.7 ≥ 82.5 ≥ 79.6 ≥ 75.0
1.1 ≥ 82.7 ≥ 84.1 ≥ 81.4 ≥ 77.7
1.5 ≥ 84.2 ≥ 85.3 ≥ 82.8 ≥ 79.7
2.2 ≥ 85.9 ≥ 86.7 ≥ 84.3 ≥ 81.9
3 ≥ 87.1 ≥ 87.7 ≥ 85.6 ≥ 83.5
4 ≥ 88.1 ≥ 88.6 ≥ 86.8 ≥ 84.8
5.5 ≥ 89.2 ≥ 89.6 ≥ 88.0 ≥ 86.2
7.5 ≥ 90.1 ≥ 90.4 ≥ 89.1 ≥ 87.3
11 ≥ 91.2 ≥ 91.4 ≥ 90.3 ≥ 88.6
15 ≥ 91.9 ≥ 92.1 ≥ 91.2 ≥ 89.6
18.5 ≥ 92.4 ≥ 92.6 ≥ 91.7 ≥ 90.1
22 ≥ 92.7 ≥ 93.0 ≥ 92.2 ≥ 90.6
30 ≥ 93.3 ≥ 93.6 ≥ 92.9 ≥ 91.3
37 ≥ 93.7 ≥ 93.9 ≥ 93.3 ≥ 91.8
45 ≥ 94.0 ≥ 94.2 ≥ 93.7 ≥ 92.2
55 ≥ 94.3 ≥ 94.6 ≥ 94.1 ≥ 92.5
75 ≥ 94.7 ≥ 95.0 ≥ 94.6 ≥ 93.1
90 ≥ 95.0 ≥ 95.2 ≥ 94.9 ≥ 93.4
110 ≥ 95.2 ≥ 95.4 ≥ 95.1 ≥ 93.7
132 ≥ 95.4 ≥ 95.6 ≥ 95.4 ≥ 94.0
160 ≥ 95.6 ≥ 95.8 ≥ 95.6 ≥ 94.3
200 ≥ 95.8 ≥ 96.0 ≥ 95.8 ≥ 94.6
250 up to 1000 ≥ 95.8 ≥ 96.0 ≥ 95.8 ≥ 94.6


 

Table 1.3    Tier 2 Performance thresholds for three-phase line operated AC motors equal to or greater than 75 kW and equal to or lower than 200 kW.

Rated Power Output (kW) Efficiency at full load (%)
2 Pole 4 Pole 6 Pole 8 Pole
75 ≥96.3 ≥96.8 ≥96.3 ≥95.4
90 ≥96.4 ≥96.9 ≥96.5 ≥95.5
110 ≥96.6 ≥97.0 ≥96.6 ≥95.8
132 ≥96.7 ≥97.1 ≥96.8 ≥95.9
160 ≥96.9 ≥97.3 ≥97.0 ≥96.1
200 ≥97.1 ≥97.4 ≥97.0 ≥96.3


Table 1.4    Tier 2 Performance thresholds for single-phase line operated AC motors

Rated Power Output (kW) Efficiency at full load (%)
2 Pole 4 Pole 6 Pole 8 Pole
0.12 ≥ 60.8 ≥ 64.8 ≥ 57.7 ≥ 50.7
0.18 ≥ 65.9 ≥ 69.9 ≥ 63.9 ≥ 58.7
0.2 ≥ 67.2 ≥ 71.1 ≥ 65.4 ≥ 60.6
0.25 ≥ 69.7 ≥ 73.5 ≥ 68.6 ≥ 64.1
0.37 ≥ 73.8 ≥ 77.3 ≥ 73.5 ≥ 69.3
0.4 ≥ 74.6 ≥ 78.0 ≥ 74.4 ≥ 70.1
0.55 ≥ 77.8 ≥ 80.8 ≥ 77.2 ≥ 73.0
0.75 ≥ 83.5 ≥ 85.7 ≥ 82.7 ≥78.4
1.1 ≥ 85.2 ≥ 87.2 ≥ 84.5 ≥80.8
1.5 ≥ 86.5 ≥ 88.2 ≥ 85.9 ≥82.6
2.2 ≥ 88.0 ≥ 89.5 ≥ 87.4 ≥84.5
3 ≥ 89.1 ≥ 90.4 ≥ 88.6 ≥85.9
4 ≥ 90.0 ≥ 91.1 ≥ 89.5 ≥87.1
5.5 ≥ 90.9 ≥ 91.9 ≥ 90.5 ≥88.3
7.5 ≥91.7 ≥92.6 ≥91.3 ≥89.3
11 ≥92.6 ≥93.3 ≥92.3 ≥90.4
15 ≥93.3 ≥93.9 ≥92.9 ≥91.2
18.5 ≥93.7 ≥94.2 ≥93.4 ≥91.7
≥22 ≥94.0 ≥94.5 ≥93.7 ≥92.1

1.4    Measurement and calculations

1.4.1    Measurement Standards and Test Requirements

Product efficiency at full load (100% of maximum continuous rated power output) shall be determined in accordance with:

  • Method 2-1-1B according to Table 2 (Induction Machines - preferred testing methods) of BS EN 60034-2-1:2014 “Rotating electrical machines – Part 2-1: Standard methods for determining losses and efficiency from tests (excluding machines for traction vehicles)”

Products shall be operated from a 400 V AC, 3 phase, 50 Hz electrical power supply during testing. (If the product is not designed to operate at this voltage, then product testing should be undertaken using a 230 V AC or 690 V AC electrical power supply, or alternatively at all rated operating voltages).

Until further notice, products listed before September 2020 will be accepted with testing performed according to BS EN 60034-2-1:2007.

If a single product is submitted for assessment, one detailed test report should be submitted. For a product range, test results may be submitted in summary form provided:

  • Sufficient data is included to confirm that product performance was determined in accordance with the procedures and test conditions laid down in the relevant standards.
  • Detailed test reports have been prepared for each product tested and are available on request for inspection, where not submitted with the application.

1.4.2    Rounding 

For the avoidance of doubt test data should be presented to 1 decimal place. As an example, a 4 pole, three-phase line operated AC motor with a rated power output of 90.0 kW and an efficiency at full load of 96.8% would be deemed to fail.

1.5    Verification for ETL Listing 

Any of the following testing routes may be used to demonstrate the conformity of products against the requirements:

  • In-house testing – Self-certified
  • In-house testing – Self-tested and verified or cross-checked by an independent body
  • Witnessed testing
  • Independent testing
  • Representative testing (see clause 1.5.1)

Further information regarding the first four routes can be found in Guidance Note 5 on the ETL product testing framework1

1.5.1    Representative testing

Where applications are being made for two or more products that are variants of the same basic design, test data may be submitted for a representative selection of models, provided that:

  • All variants are of the same product range as the representative models and the primary variations between models are rated power and physical dimensions.
  • All variants are constructed from the same materials.
  • A detailed test report is provided for at least one representative product in each range.
  • The representative model is in the bottom quartile of predicted performance within each range.
  • Clear descriptions and formulae describing the relationship between the representative model(s) and the variants are provided.

It should be noted that:

  • If a manufacturer voluntarily removes the representative model from the ETL then other products linked with that representative model may or may not be permitted to remain on the ETL.
  • If any product submitted under these representative model rules is later found not to meet the performance criteria when independently tested, then all products based on the same representative model will be removed from the ETL.  

1.6    Conformity testing

Products listed on the ETL may be subject to the scheme’s conformity testing programme in order to ensure listed models continue to meet the ETL requirements.

1.7    Effective Date

These criteria will take effect from September 2020. Tier 2 requirements will automatically take effect from April 2023.

1.8    Review 

1.8.1    Indicative review date 

The next technical review is scheduled for 2024-25. 

1.8.2    Illustrative future direction of requirements   

Future changes to the specification may include:

  • Updates to efficiency thresholds to precede the implementation of stricter Ecodesign requirements for electric motors. 


[1] https://www.gov.uk/government/publications/energy-technology-list-etl-product-testing-framework