In order to test the properties of a sample of electrical steel, a set of laminations of the form of figure have been stamped out of a sheet of the electrical steel of thickness 3.0 mm. The radii of the laminations are Ri = 75 mm and Ro = 82 mm. They have been assembled in a stack of 10 laminations (separated by appropriate insulation to eliminate eddy currents) for the purposes of testing the magnetic properties at a frequency of 100 Hz.

a. The flux in the lamination stack will be excited from a variable-amplitude, 100-Hz voltage source whose peak amplitude is 30 V (peak-to-peak). Calculate the number of turns N1 for the excitation winding required to insure that the lamination stack can be excited up to a peak flux density of 2.0T.

b. With a secondary winding of N2 = 20 turns and an integrator gain G = 1000, the output of the integrator is observed to be 7.0 V peak-to-peak. Calculate (i) the corresponding peak flux in the lamination stack and (ii) the corresponding amplitude of the voltage applied to the excitationwinding.

1 < < R, R, =Gft; dt Winding 2. Na turns Winding 1. N turns Stack of n laminations, cach of thickness A