Karimmohamedselfstudyassig
.pdf
School
Cairo University**We aren't endorsed by this school
Course
ELC 102
Subject
Electrical Engineering
Date
Dec 17, 2024
Pages
3
Uploaded by karimhilal02
Step 1: Select Core Sizes Let's use some standard ferrite core options based on typical EE and EC core sizes that match the requirements. For the EE Core « Assume an EE 42/21/15 core (common size): o A.=136cm? = 1.36 x 10~*m? o A, —18cm? o Effective magnetic path length I, = 10.5 cm = 0.105 m For the EC Core ® Assume an EC 41/20/15 core: e A, =117cm? = 1.17 x 10~ m? o A,—=21cm? o Effective magnetic path length I, = 10cm = 0.1 m Step 2: Calculate Gap Length I, and Number of Turns N' Using the formulas from earlier, we'll plug in these core parameters for both core types. EE Core Calculations 1. Gap Length I: Lxl, 0.0004 x 0.105 [ . = ~0.024m = 2.4mm oA, dmx 107 x 136 x 10 2. Number of Turns N: _[m, [ ooo0ix002% N =\ oa. ~V im w107 x 1.36 < 101~ 22tumms
EC Core Calculations 1. Gap Length l,: _Lxl ___ 00004x01 97 A, Amx 1077 x 117 x 104 2. Number of Turns N: N .| He _ [ 0.0004x0027 45 turns HoAc 47 x 1077 x 1.17 x 1074 Step 3: Wire Size and Resistance 1 ~0.027m = 2.7mm 1. Current Density: Assume a current density of 4.5 A./mm”, which is typical for ferrite cores at room temperature. 2. Wire Size: Using Inax = 5.5 A, we select a wire cross-section that supports this current density: ) 55 ) Cross-sectional area = I 1.22mm’ This corresponds to roughly AWG 17 wire. 3. Winding Resistance: Given that P, < 1 W, Py 1 <z R<p 5w The length of the wire can be approximated from the core window area, and we can check that the chosen AWG 17 wire will maintain a resistance < 0.033 2 over this length.
Results and Comparison Parameter EE Core (EE 42/21/15) Core Area A, 1.36 cm? Window Area A, 1.8 cm? Gap Length [, 2.4 mm Number of Turns N 42 Wire Size AWG 17 Copper Loss <1W Comments EC Core (EC 41/20/15) 1.17 cm? 2.1 cm? 2.7 mm 45 AWG 17 <1W e Both core types meet the design requirements, but the EC core requires a slightly larger gap due to its smaller cross-sectional area, which can lead to slightly higher fringing losses. e The EC core has a slightly larger window area than the EE core, which could allow for easier winding and potentially lower copper losses if additional space is used efficiently. e Either core is suitable, but the EE core might be slightly more efficient for this design due to its slightly lower gap requirement.