ADAMSON UNIVERSITYCollege of Engineering

Electronics Engineering DepartmentASSIGNMENT

1. 20 pointsA toroid of rectangular cross section has r1 = 8 cm, r2 = 10 cm, a = 2 mm, N = 200, and = 9000. Assuming a uniform flux density of 0.95Tesla in the core. Calculate the current of the coil.

2. 20 pointsA coil of 400 turns is wound around an iron ring of mean circumference 400mm and cross-

section of 350mm2. If the coil has a resistance of 6 ohms and is connected to a 12 V dc supply, calculate;

a. mmfb. magnetizing forcec. reluctanced. flux

Assume the value of relative permeability as 1100.

3. 20 pointsA simplified rotor and stator for a dc motor is shown in the figure below. The mean path

length of the stator is 50cm, and its cross-sectional area is 12cm2. The mean path length of the rotor is 5cm, and its cross-sectional area also may be assumed to be 12cm2. Each air gap between the rotor and the stator is 0.05cm wide, and the cross-sectional are of each air gap (including fringing) is 14cm2. The iron of the core has a relative permeability of 2000, and there are 200 turns of wire on the core. If the current in the wire is adjusted to be 1 A, what will the resulting flux density in the air gaps be?