Motor Efficiency Calculator
Efficiency, losses and the yearly cost of those losses for a motor.
Results
Efficiency
89.286
%
Power
0.900
kW
Energy
5256
kWh/a
Cost
946.08
What this tool does
The gap between what a motor draws and what it delivers is paid for every hour it runs, and over a year it usually dwarfs the price of the motor itself. That is the whole argument behind efficiency classes: a two-point gain on a machine running two shifts pays back quickly.
Formula
η = P output ÷ P down payment × 100
Variables
| Symbol | Meaning | Unit |
|---|---|---|
po | Output power | kW |
pin | Input power | kW |
h | Hours per day | h |
pr | Price per kWh | — |
EF | Efficiency | % |
LO | Power | kW |
EY | Energy | kWh/a |
CY | Cost | — |
Worked example
- Output power7.5 kW
- Input power8.4 kW
- Hours per day16 h
- Price per kWh0.18
- Efficiency89.286 %
- Power0.900 kW
- Energy5256 kWh/a
- Cost946.08
Limitations
- The result is an estimate based only on the values you type. Real situations often include factors this calculator does not know about.
- Electrical installations are governed by national wiring rules. Cable sizing also depends on installation method, grouping, ambient temperature and protection devices, which this calculator does not evaluate.