Question

What is the formula for the area per pole of damper pass provided?

(a) area per pole of damper pass = 0.2 * specific electric loading * pole pitch * current density in damper bars

(b) area per pole of damper pass = 0.2 * specific electric loading * pole pitch / current density in damper bars

(c) area per pole of damper pass = 0.2 * specific electric loading – pole pitch / current density in damper bars

(d) area per pole of damper pass = 0.2 + specific electric loading * pole pitch / current density in damper bars

I have been asked this question during an internship interview.

Query is from Design of Rotor topic in division Design of Synchronous Machines of Design of Electrical Machines

Answer 1

The correct answer is (b) area per pole of damper pass = 0.2 * specific electric loading * pole pitch / current density in damper bars

The explanation is: The specific electric loading and the pole pitch is calculated first. Next the current density in damper bars is next calculated. Substituting in the above formula gives the area per pole of damper pass provided.