Efficiency

Overview

Engineering reference data for Efficiency in miscellaneous.

Key Formulas

Unit Conversion

$y = x \cdot k$

Multiply by conversion factor.

Linear Interpolation

$y = y_1 + \frac{(x - x_1)(y_2 - y_1)}{x_2 - x_1}$

Estimate between two known points.

Percentage

$p = \frac{\text{part}}{\text{whole}} \times 100\%$

Part as fraction of whole.

Variables

Symbol	Description	Unit
$x$	Input value	—
$y$	Output value	—
$k$	Conversion factor	—

Practical Examples

Electric Motor Efficiency

Consider an electric motor with an input power of 2000 W and an output power of 1800 W delivered to the shaft. The efficiency is calculated as:

$\mu = \frac{W_o}{W_i} = \frac{1800 \, \text{W}}{2000 \, \text{W}} = 0.9 = 90\%$

This indicates that 90% of the electrical input power is converted into useful mechanical work.

Wind Turbine Efficiency

For a wind turbine, the theoretical energy potential under given wind conditions is 300 kWh. If the actual energy produced is 70 kWh, its efficiency is:

$\mu = \frac{70 \, \text{kWh}}{300 \, \text{kWh}} \approx 0.23 = 23\%$

This highlights the practical challenges in capturing energy from variable natural sources.

References

• Original Source