LAB 4 - FAN system Data w. Calculations

# LAB 4 FAN system - Test 3 Tj =[2Qtop(Rj-c Rc-amb Tc Double Qtop and Tj 108.8848 Test 3 Tjunction(Tj Board Temp(Tboard Voltage on Resistor 61.1000

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Date Station No. Heatsink Description Test Run Time Chassis Temp (Tamb) Case Temp(Tcase) Test 1 18.0000 28.0000 56.9000 Test 2 14.0000 25.5000 58.3000 Test 3 10.0000 27.8000 56.0000 Test 4 11.0000 25.3000 55.0000 Test 5 8.0000 23.9000 62.2000 1.0000 Parallel w/ hi imp 2.0000 Parallel w/ lo imp 3.0000 Series w/ hi imp 4.0000 Series w/ lo imp 5.0000 Natural (fans off) CALCULATIONS Part 1. P= V^2 * R R= 2 Ohms Pactual=5^2/1 Voltage on Resistor Vr ^2 (.48) = Test 1 4.8900 Test 2 4.8900 Test 3 4.8900 Test 4 4.8900 Test 5 4.8900 Part3. L = 90mm W = 58mm Lthick = 20mm Kfr4 = .23 W/mK 0.0900 0.0580 0.0200 0.2300 Rair = 1/(hA) 19.1571 Rpcb = Lthick/(KA) RtotPCB = Rair + Rpcb 35.8154 Qpcb = (Tb-Tamb)/(Rto Q = P( R )

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Part4. Qtot-Qpcb = Qtop Test 1 11.1994 Test 2 11.1324 Test 3 11.2106 Test 4 11.1966 Test 5 11.1184 Part5. Qtot=(Tc-Tamb)/Rth Tc = (Qtot * Rc-amb )Tamb Tj = {Qtot*(Rj-c)}+Tc 48.1253 52.3253 Series fans with high impedance Part6. Qtot-Qpcb = Qtop

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Unformatted text preview: Test 3 Tj = [2Qtop*(Rj-c + Rc-amb)]+ Tc Double Qtop and Tj; 108.8848 Test 3 Tjunction (Tj) Board Temp (Tboard) Voltage on Resistor 61.1000 34.0000 4.8900 62.5000 33.0000 4.8900 60.2000 33.5000 4.8900 59.2000 32.0000 4.8900 66.0000 36.0000 4.8900 Power ratio = Pheat / Pactual 2.0833 0.4800 Part2. NO HEAT LOSS at PC Rth= Ti-To / Q (Tj-Tcase)/Q Qtot (W) R-(Junc-Case) 11.9561 0.3513 11.9561 0.3513 11.9561 0.3513 11.9561 0.3513 11.9561 0.3178 A = L*W Heat Coeff. Air = 10 W/[(m^2)*k] K-value FROM GOOGL 0.0052 10.0000 16.6583 otPCB) Test 1 0.7567 Test 2 0.8237 Test 3 0.7455 Test 4 0.7594 Test 5 0.8376 Ramb = 1.7 Assumed no Q at PCB # is off is because I considered Qpcb (12/25) 0.4800 Board (Tcase-Tamb)/Qtop R-(Case-Amb) [W/K] 2.4172 2.7434 2.3586 2.4841 3.2034 LE...
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## This note was uploaded on 09/08/2010 for the course ME 115 at San Jose State University .

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LAB 4 FAN system - Test 3 Tj =[2Qtop(Rj-c Rc-amb Tc Double Qtop and Tj 108.8848 Test 3 Tjunction(Tj Board Temp(Tboard Voltage on Resistor 61.1000

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