Belt driven Fans - Fan vs. Motor Speed
Belt driven fans are used in heating, ventilation, air-conditioning and cooling (HVAC) systems.
The speed of a fan wheel versus the speed of the motor with a belt drive can be calculated as
df nf = dm nm (1)
where
df = pulley diameter fan (inch, mm)
nf = speed of fan (rpm - rounds per minute)
dm = pulley diameter motor (inch, mm)
nm = speed of motor (rpm - rounds per minute)
Example - Speed of Fan
A synchronous electrical motor rotates with speed 1000 rpm. The motor pulley diameter is 76.5 mm and the fan pulley diameter is 205.5 mm. The speed of the fan can be calculated by modifying (1) to
nf = dm nm / df
- or with values:
nf = (76.5 mm) (1000 rpm) / (205.5 mm)
= 372 rpm
Related Topics
• Ventilation
Systems for ventilation and air handling - air change rates, ducts and pressure drops, charts and diagrams and more.
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