1. A magnetic circuit containing a ferromagnetic core with an air-gap is shown in Fig. 1.1. The ferromagnetic core has a square cross-section (wxw) and is made from a material with a relative permeability 12000. The core is excited by two coils: Coil 1 (N₁ = 1000 turns, current 1 A) and Coil 2 (N2 = 780 turns, current 12). The required magnetic flux density in the air-gap is B, = 2.2 T. I₁=1 A H-12000 N₁ = 1000 turns Air-gap width 5=2 mm (drawing not to scale) N₂ = 780 turns h=0.125 m w=0.012 m d=0.25 m Figure 1.1. (a) In magnetic circuit analysis, what is meant by the term 'fringing', and how are the effects of fringing usually accounted for in the calculation process? (b) Calculate the mean flux path length l of the magnetic core. (c) Calculate the reluctance Rc (H-1) of the magnetic core. (d) Calculate the reluctance R, (H-1) of the air-gap. (Do not ignore fringing.) (e) Why is it frequently possible to ignore the reluctance of the core in magnetic circuits that contain an air-gap? (f) Calculate the magnetic flux + (Wb). (g) Calculate the magnetic field intensity Hc (A/m) in the core.

1. A magnetic circuit containing a ferromagnetic core with an air-gap is shown in Fig. 1.1. The ferromagnetic core has a square cross-section (wxw) and is made from a material with a relative permeability 12000. The core is excited by two coils: Coil 1 (N₁ = 1000 turns, current 1 A) and Coil 2 (N2 = 780 turns, current 12). The required magnetic flux density in the air-gap is B, = 2.2 T. I₁=1 A H-12000 N₁ = 1000 turns Air-gap width 5=2 mm (drawing not to scale) N₂ = 780 turns h=0.125 m w=0.012 m d=0.25 m Figure 1.1. (a) In magnetic circuit analysis, what is meant by the term 'fringing', and how are the effects of fringing usually accounted for in the calculation process? (b) Calculate the mean flux path length l of the magnetic core. (c) Calculate the reluctance Rc (H-1) of the magnetic core. (d) Calculate the reluctance R, (H-1) of the air-gap. (Do not ignore fringing.) (e) Why is it frequently possible to ignore the reluctance of the core in magnetic circuits that contain an air-gap? (f) Calculate the magnetic flux + (Wb). (g) Calculate the magnetic field intensity Hc (A/m) in the core.

Introductory Circuit Analysis (13th Edition)

13th Edition

ISBN:9780133923605

Author:Robert L. Boylestad

Publisher:Robert L. Boylestad

Chapter1: Introduction

Section: Chapter Questions

Problem 1P: Visit your local library (at school or home) and describe the extent to which it provides literature...

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