barcode reader in asp.net codeproject Magnetic Structure with Air Gaps in Software

Making Quick Response Code in Software Magnetic Structure with Air Gaps

EXAMPLE 163 Magnetic Structure with Air Gaps
Read QR Code In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Print Quick Response Code In None
Using Barcode generator for Software Control to generate, create QR image in Software applications.
Problem
QR Code JIS X 0510 Reader In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
Encode QR-Code In Visual C#
Using Barcode maker for Visual Studio .NET Control to generate, create Denso QR Bar Code image in .NET applications.
Compute the equivalent reluctance of the magnetic circuit of Figure 1618 and the ux density established in the bottom bar of the structure
Quick Response Code Generator In VS .NET
Using Barcode printer for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
QR Code JIS X 0510 Maker In VS .NET
Using Barcode generation for Visual Studio .NET Control to generate, create Denso QR Bar Code image in VS .NET applications.
i=lA 100 turns 001 m 005 m
QR Code JIS X 0510 Generation In VB.NET
Using Barcode generator for VS .NET Control to generate, create Denso QR Bar Code image in .NET applications.
Paint European Article Number 13 In None
Using Barcode creation for Software Control to generate, create EAN-13 image in Software applications.
001 m Bottom plate 0025 m
GTIN - 12 Drawer In None
Using Barcode printer for Software Control to generate, create GS1 - 12 image in Software applications.
Create Barcode In None
Using Barcode creation for Software Control to generate, create barcode image in Software applications.
001 m
Data Matrix ECC200 Generator In None
Using Barcode generation for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
Encode GS1-128 In None
Using Barcode generator for Software Control to generate, create EAN 128 image in Software applications.
01 m
Create Ames Code In None
Using Barcode creation for Software Control to generate, create Ames code image in Software applications.
Code-39 Creator In None
Using Barcode generator for Office Excel Control to generate, create Code39 image in Microsoft Excel applications.
Figure 1618 Electromagnetic structure with air gaps
Printing Barcode In Visual Studio .NET
Using Barcode maker for ASP.NET Control to generate, create bar code image in ASP.NET applications.
UPC Symbol Generator In Java
Using Barcode generation for Java Control to generate, create UPCA image in Java applications.
00 1m
Barcode Generator In None
Using Barcode maker for Online Control to generate, create bar code image in Online applications.
UPC Symbol Maker In Objective-C
Using Barcode creator for iPhone Control to generate, create UPC Code image in iPhone applications.
0005m
EAN-13 Supplement 5 Creation In Java
Using Barcode encoder for Android Control to generate, create EAN 13 image in Android applications.
Code 3/9 Encoder In None
Using Barcode encoder for Microsoft Word Control to generate, create Code 39 Full ASCII image in Office Word applications.
Part III
Electromechanics
Solution
Known Quantities: Relative permeability; number of coil turns; coil current; structure
geometry
Find: Req ; Bbar Schematics, Diagrams, Circuits, and Given Data: r = 10,000; N = 100 turns; i =
1 A
Assumptions: All magnetic ux is linked by the coil; the ux is con ned to the magnetic core; the ux density is uniform Analysis:
Calculation of magnetomotive force From equation 1628, we calculate the magnetomotive force: F = mmf = N i = (100 turns)(1 A) = 100 A t
Calculation of mean path Figure 1619 depicts the geometry The path length is: l c = l1 + l 2 + l 3 + l 4 + l 5 + l 6 + l g + l g However, the path must be broken into three legs: the upside-down U-shaped element, the air gaps, and the bar We cannot treat these three parts as one because the relative permeability of the magnetic material is very different from that of the air gap Thus, we de ne the following three paths, neglecting the very small (half bar thickness) lengths l5 and l6 : l U = l1 + l 2 + l 3 where lU = 018 m lbar = 009 m lgap = 005 m lbar = l4 + l5 + l6 l4 lgap = lg + lg
009 m l1 l2
0045 m
l5 l4
l6 0025 m
Next, we compute the cross-sectional area For the magnetic structure, we calculate the square cross section to be: A = w 2 = (001)2 = 00001 m2 For the air gap, we will make an empirical adjustment to account for the phenomenon of fringing, that is, to account for the tendency of the magnetic ux lines to bow out of the magnetic path, as illustrated in Figure 1620 A rule of thumb used to account for fringing is to add the length of the gap to the actual cross-sectional area Thus: Agap = (001 m + lg )2 = (00125)2 = 015625 10 3 m2 3 Calculation of reluctance Knowing the magnetic path length and cross sectional area we can calculate the reluctance of each of the legs of the circuit: RU = lU 018 lU = = U A r 0 A 10,000 4 10 7 00001
Ferromagnetic material
Air gap
= 143 105 A t/Wb Rbar = lbar lbar 009 = = bar A r 0 A 10,000 4 10 7 00001
Lines of flux
= 0715 105 A t/Wb Rgap = lgap lgap 005 = = = 255 107 A t/Wb gap Agap 0 Agap 4 10 7 00001
Figure 1620 Fringing effects in air gap
Note that the reluctance of the air gap is dominant with respect to that of the magnetic
16
Principles of Electromechanics
structure, in spite of the small dimension of the gap This is because the relative permeability of the air gap is much smaller than that of the magnetic material The equivalent reluctance of the structure is: Req = RU + Rbar + Rgap = 143 105 + 0715 105 + 255 107 = 257 107 Thus, Req Rgap Since the gap reluctance is two orders of magnitude greater than the reluctance of the magnetic structure, it is reasonable to neglect the magnetic structure reluctance and work only with the gap reluctance in calculating the magnetic ux Calculation of magnetic ux and ux density in the bar From the result of the preceding sub-section, we calculate the ux = F F 100 A t = 392 10 6 Wb = Req Rgap 255 107 A t/Wb 392 10 6 Wb = = 392 10 3 Wb/m2 A 00001 m2
and the ux density in the bar: Bbar =
Comments: It is very common to neglect the reluctance of the magnetic material
sections in these approximate calculations We shall make this assumption very frequently in the remainder of the chapter
EXAMPLE 164 Magnetic Structure of Electric Motor
Problem
Figure 1621 depicts the con guration of an electric motor The electric motor consists of a stator and of a rotor Compute the air gap ux and ux density
Copyright © OnBarcode.com . All rights reserved.