ELECTRICAL MACHINES ASSIGNMENT
Fall 2016 Homework 2 - Electrical Machines
1.1 A magnetic circuit with a single air gap is shown in Fig. 1.27. The core dimensions are:
Cross-sectional Area Ac = 3.5 cm^2
Mean core length le = 25 cm
Gap length g = 2.4 mm
N = 95 turns
Assume that the core is of infinite permeability (-∞) and neglect the effects of fringing fields at the air gap and leakage flux.
a) Calculate the reluctance of the core Re and that of the gap Rg.
b) For a current of i = 1.4 A, calculate the total flux.
c) Calculate the flux linkages of the coil.
d) Calculate the coil inductance L.
Core: mean length l, area A, permeability p
Coil: N turns
Air gap
Figure 1.27: Magnetic circuit for Problem 1.1.
1.2 Repeat Problem 1.1 for a finite core permeability of μ = 2350.
1.3 Consider the magnetic circuit of Fig. 1.27 with the dimensions of Problem 1.1. Assuming infinite core permeability, calculate:
a) The number of turns required to achieve an inductance of 15 mH.
b) The inductor current which will result in a core flux density of 1.15 T.