What does the table of motor efficiency classes in The Energy and Resources Institute (TERI) Veraval seafood profile, international efficiency class 2 (IE2) to class 3 (IE3), really say about energy saved?

The profile prints a saving of 2.7% for a 2.2 kilowatt motor moving from IE2 to IE3. That number is the gap between the two efficiency figures in points. The energy saved for the same work works out nearer 3.1%, so the printed column slightly understates it.

What the table prints

The profile lists five two-pole motors with an IE2 efficiency, an IE3 efficiency and a column headed "percentage energy saving", and credits a Siemens IE3 motor brochure.

• 2.2 kilowatts (kW): 83.2% to 85.9%, printed saving 2.7
• 3.7 kW: 85.5% to 87.8%, printed saving 2.3
• 5.5 kW: 87% to 89.2%, printed saving 2.2
• 7.5 kW: 88.1% to 90.1%, printed saving 2
• 11 kW: 89.4% to 91.2%, printed saving 1.8

What those numbers are

Subtract the IE2 column from the IE3 column and you get 2.7, 2.3, 2.2, 2.0 and 1.8 on the five rows. The printed column is therefore the efficiency gap in percentage points. It is not the share of electricity saved. This is our reading of the arithmetic; the profile does not say how the column was made.

The saving in energy

For the same shaft output, input power is output divided by efficiency. The saving is 1 minus old efficiency divided by new efficiency. On the five rows that gives about 3.1%, 2.6%, 2.5%, 2.2% and 2.0%. So the printed column slightly understates the saving; it does not overstate it.

What the profile says around the table

• Rewinding a motor drops its efficiency by 3 to 5%, so motors rewound three times or more are better replaced.
• Reciprocating chillers have 50 horsepower and 75 horsepower motors, currently IE2. The table stops at 11 kW, so it gives no saving for those sizes; do not read the percentages across.
• Simple payback is given as 2 to 3 years for replacing old rewound motors with IE3.

An 11 kW motor on a seafood plant pump, financial year (FY) 2025-26 factor (example)

• Input at IE2: 11 / 0.894 = 12.30 kW. Input at IE3: 11 / 0.912 = 12.06 kW. Difference: 0.243 kW
• Saving: 0.243 / 12.30 = 2.0%, against 1.8 printed
• At 6,000 hours a year at full load: 0.243 x 6,000 = about 1,457 kilowatt hours (kWh)
• Carbon dioxide (CO2): 1,457 x 0.675 kg = about 984 kg a year

The 6,000 hours and full load are example values. Use your own metered hours and the motor's real load, which is usually lower.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so motor-driven plants can see their monthly kilowatt hours before and after a swap. Senseible does not read motor nameplates or measure load, so the efficiency figures come from the motor datasheet.

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Sources: Cluster profile of Veraval seafood processing industries, The Energy and Resources Institute (motor table and text), Central Electricity Authority (CEA), CO2 Baseline Database for the Indian Power Sector, version 22.0 (0.675 kg CO2 per kWh, FY 2025-26)

Last reviewed 2026-11-06. Efficiency figures are the profile's own printed values. Replace them with the datasheet values of the motor you are buying.