Question

What is the formula for the number of blades?

(a) number of blades = 3.14 * outside diameter * (1.25 – 1.5)* width of fan

(b) number of blades = 3.14 / outside diameter * (1.25 – 1.5)* width of fan

(c) number of blades = 3.14 * outside diameter / (1.25 – 1.5)* width of fan

(d) number of blades = 3.14 * outside diameter * (1.25 – 1.5) / width of fan

The question was asked in my homework.

The query is from Design of Fan in section Aspects of Design of Mechanical Parts of Design of Electrical Machines

Answer 1

The correct answer is (c) number of blades = 3.14 * outside diameter / (1.25 – 1.5)* width of fan

To elaborate: The outside diameter and the width of fan is first calculated. Then the range is fixed according to the diameter and on substitution gives the number of blades.