Question

What is the formula in order to check the rigidity?

(a) moment of inertia ≥ (weight of magnetic frame * radius^2 * 10^-6) / 225

(b) moment of inertia ≤ (weight of magnetic frame * radius^2 * 10^-6) / 225

(c) moment of inertia = (weight of magnetic frame * radius^2 * 10^-6) / 225

(d) moment of inertia < (weight of magnetic frame * radius^2 * 10^-6) / 225

I had been asked this question in homework.

This question is from Frames of D.C. & A.C. Machines in portion Aspects of Design of Mechanical Parts of Design of Electrical Machines

Answer 1

Correct answer is (a) moment of inertia ≥ (weight of magnetic frame * radius^2 * 10^-6) / 225

Easy explanation: The moment of inertia, the weight of magnetic frame and the radius is calculated first. The machine is highly rigid if the moment of inertia is greater than or equal to the product of weight of magnetic frame and square of radius divided by 225.