Xin Feng Classroom | Ventilator Series Fan Parameter Conversion Formulas

The flow conversion formula for fans is as follows: 

m³/h = 101325 (standard atmospheric pressure) × Nm³/h × (273 + T) / 273 / local atmospheric pressure Note that T represents the medium temperature.

Motor power is: Required power = Q × P / 3600 / 1000 / mechanical efficiency / Fan efficiency*K Mechanical efficiency Direct motor connection: 1.0 Direct coupling transmission: 0.98 Reducer transmission: 0.95 V-belt transmission: 0.92 K values: Induced draft fan: 1.2-1.25 Forced draft fan: 1.1-1.15 Variable frequency: 1.05-1.1  Fluid coupling 1.05-1.1  Pulverized coal fan 1.2 Select appropriate motor based on requirements。

Some customers report dust being drawn in during operation. Does this affect the fan's parameter calculations? It definitely has an impact. When dust content is below 100 mg/m³, this minor amount can be disregarded. However, if dust content reaches g/m³, a dust content coefficient must be calculated. Multiply the calculated required power by this coefficient to account for power loss due to dust ingress in the fan. Shaft Power = Q × P / 3600 / 1000 / Mechanical Efficiency / Fan Efficiency Internal Power = Q × P / 3600 / 1000 / Fan Efficiency (Q: Flow rate, unit: m³/h; P: Total pressure, unit: Pa)

Do we also need to calculate the damper torque? Of course. Damper torque calculation: M = Q × P × 2 (safety factor) × 6.4 × 10⁻⁷ Unit: N·m For F-type dampers, the minimum value can be 1.5 (when the damper operates smoothly without any sticking).    

    Who knew regulating dampers involved so many considerations? What if my fan is driven by a coupling? How should I calculate the appropriate value then?

The torque calculation formula for this coupling is as follows:

M = 9550 × motor power / fan rotational speed / 9.8, unit: kg·m

M = 9550 × motor power / fan rotational speed, unit: N·m

Got it, almost forgot. Now that we have the airflow and know the motor power, what about the fan's dynamic pressure? How do we calculate it?

The formula for calculating a fan's dynamic pressure is as follows:

Pd = ρ × C² / 2

ρ = Gas density (kg/m³)

C = Gas velocity

C = Q / 3600 / (Cross-sectional area)

Q = Flow rate (m³/h)

Cross-sectional area = (Area in m²)