Does a motor rewound more than five times use 2.5 times the power, as the Alwar manual says?

Not as it reads. The Bureau of Energy Efficiency (BEE) Alwar manual says motors rewound more than 5 times use "approx 2.5 times more power consumption". Its sum and a linked report show 32 kilowatts against 30 and 37 against 32.81, which is 7% to 13% more. Our reading: "2.5 times more" is loose and may mean less.

What the manual says

• The background to its motor measure says: "the maximum of motors are re-winded more than 5 times which leads to approx 2.5 times more power consumption and lower operating efficiency".
• Beside it: efficient motors run "typically 3 to 4 percentage points higher" in efficiency, and "4-5 % efficiency higher" in the sum, with "higher working efficiency up to 4 %" in the background.

What its own sums show

• The 50 horse power (hp) sum in the manual: a standard or re-wound motor draws 32 kilowatts (kW), an efficient one 30 kW. That is 32 / 30 = 1.07, or 7% more.
• The 50 hp kolhu report from the same programme: 37 kW today, 32.81 kW with the new motor, saving 4.19 kW. 37 / 32.81 = 1.13, or 13% more. It gives the old motor's efficiency as about 83% against 93.6%, and old motors generally as in the range of 70 to 85%.
• Check: 37 x 83 / 93.6 = 32.81 kW, so the report's own numbers tie.

Why 2.5 times cannot be the whole picture

Your motor draws what the machine needs plus what the motor wastes as heat. A worn motor wastes more, but the machine's need is still there. If the old motor drew 2.5 times the new one's power, the old motor would have to be turning most of the bill into heat.

On the report's numbers: 93.6% / 2.5 = 37.4% efficiency. That is far below the 70 to 85% the same report gives for old motors. So read the phrase as loose wording, not a measure. This is our reading; the manual does not explain it.

How to find your own motor's loss

1. With a clamp meter or a meter on the motor's line, note the kilowatts it draws on a normal load.
2. Ask the supplier for the input kilowatts of an efficient motor of the same output at that load.
3. The difference is your saving per hour. Multiply by your running hours.

The claim against the sums

• If 2.5 times were true: 30 kW x 2.5 = 75 kW for the old motor, against the manual's 32 kW
• On the kolhu report: 32.81 kW x 2.5 = 82 kW, against its 37 kW
• Efficiency check: 93.6% / 2.5 = 37.4%, against the report's 83%
• The report's real gap: 4.19 kW x 3,000 hours (10 hours a day, 300 days) = 12,570 kilowatt hours (kWh), printed as 12,571
• Carbon dioxide (CO2) at 0.675 kg a kWh, the financial year 2025-26 grid factor: 12,571 x 0.675 = 8,486 kg, about 8.5 tonnes a year for one motor

kW, efficiencies, hours and the 12,571 kWh are the reports' own; the 2.5 times lines and the CO2 are our arithmetic.

What Senseible does here

Senseible reads fuel invoices and electricity bills into monthly records, so the kWh for each bill you upload is on file by month. The bill shows the whole mill's electricity, not one motor's; for that you need a meter on each line or a few days of readings.

• Alwar efficient motor reports by size
• Alwar motor saving: 14 lakh or 148 lakh units
• Motor horsepower to kWh estimate
• Check your own number

Sources: Bureau of Energy Efficiency (BEE), Manual on energy conservation measures in oil mills, Alwar cluster (SAMEEEKSHA), Bureau of Energy Efficiency (BEE), Detailed project report: energy efficient motor for kolhu, 50 horse power, Alwar oil mill cluster (SAMEEEKSHA), Central Electricity Authority (CEA), CO2 Baseline Database for the Indian Power Sector, version 22.0 (grid factor 0.675 kg CO2 per kWh, FY 2025-26)

Last reviewed 2026-11-07. Quotes are from the BEE Alwar manual (sections 3.4.1.1 to 3.4.1.3) and the 50 hp kolhu report. The kolhu report's table also lists 56 kW as the motor's power consumption while its text and annexure imply 37 kW; we used the 37 kW that ties to its saving. Measure your own motor before you rely on either.