Fan Motors Torque

Overview

Engineering reference data for Fan Motors Torque in electrical engineering.

Key Formulas

Ohm's Law

$V = IR$

Voltage = Current × Resistance.

Power

$P = VI = I^2R = V^2/R$

Electrical power.

Energy

$E = Pt$

Energy = Power × Time.

Variables

Motor Starting Torque Formula

For belt-driven fans, the motor must overcome the combined inertia of the fan wheel and drive system to accelerate to operating speed. The required moment of inertia at the motor shaft is calculated as:

$I_m = 1.1 \cdot I_f \cdot \left( \frac{n_f}{n_m} \right)^2$

Important Note: For direct-drive fans, the motor moment of inertia ($I_m$) will always exceed the fan wheel moment of inertia ($I_f$) because the motor must directly spin the fan wheel without the mechanical advantage of a belt system.

Backward Centrifugal Wheel Inertia Data

The following tables provide typical moment of inertia values for backward-inclined centrifugal fan wheels, a critical parameter for motor sizing calculations.

Interactive Charts

References

• Original Source