Energy
Motor Efficiency Calculator
Calculate motor input power, energy losses and annual cost of losses from output power, efficiency and operating hours.
Motor Power Loss
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Estimated electrical input power converted to motor losses at the entered efficiency.
Mechanical output power
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Electrical input power
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Motor power loss
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Power lost
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Annual electrical energy input
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Annual useful mechanical energy
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Annual motor energy loss
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Annual electricity cost
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Annual cost of motor losses
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Method:
Motor efficiency is:
Efficiency =
Output Power ÷ Input Power
Therefore electrical input power is:
Input Power =
Output Power ÷ Efficiency
Motor power loss is:
Power Loss =
Input Power − Output Power
Annual electrical energy input is:
Energy Input =
Input Power × Operating Hours
Annual motor energy loss is:
Energy Loss =
Power Loss × Operating Hours
Annual cost of losses is:
Cost of Losses =
Energy Loss × Electricity Tariff
This calculator assumes the entered motor efficiency represents the efficiency at the actual operating load.
Motor efficiency can vary with load, voltage, motor design, age and operating conditions. Nameplate or rated efficiency may not represent actual part-load efficiency.
For detailed energy audits, use measured electrical input power and actual shaft output where available.