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Unformatted text preview: ECE 430 Exam #1, Fall 2010 Name: 30 LUT 1 0 M S
90 Minutes Section (Check One) MWF 10am MWF 2pm
1. / 25 2. / 25
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with total impedance (0.5 + j1.0)Q . The load has a power factor of 0.85 lag and it draws a current with magnitude 8 Amps (RMS). What is the magnitude of the voltage across the load?
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connected load through a transmission line having a perphase impedance magnitude of 1.5
Ohms and angle 75 degrees. The deltaconnected load consumes a total threephase apparent
power of 450 kVA at 0.8 power factor lag when the generator voltage is set so that the voltage at
the load is 4,160 Volts (line to line).  a) Find the magnitude of the generator line current for this system.
b) Find the magnitude of the lineline voltage of the generator.
0) Find the total threephase complex power supplied by the generator. PCP we... Ezpwdm'l— IA I Lem—c I
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hence the magnetic reluctance of the metal materials can be ignored. The dimensions of the air gaps are summarized in the ﬁgure. Ignore fringing effects. Gap 1: Distance: 5 mm; cross—sectional area: 1 cm2
Gap 2: Distance: 6 mm; crosssectional area: 0.5 cm
Gap 3: Distance: 5 mm; crosssectional area: 1 cm2 2 a) Identify the dot marking of the two coils;
b) Draw the magnetic equivalent circuit;
c) Find the ﬂux density in air gap 1 if i1=10 Amps (DC)and i2=20 Amps (DC) : 3.970] X109 F”: wk More space on next page Blank page for more space (:3 gm“ = ? KVL
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circuited. When a 60Hz sinusoidal voltage of 120 Volts (RMS) is applied to coil #1, the coil #1 current is 6
Amps (RMS) and the voltage measured on the open—circuited coil #2 is 70 Volts (RMS). a) What are the self inductances of coil #1 and #2 in Henries? b) What is the magnitude of the mutual inductance between coil #1 and coil #2 in Henries? c) What are the current magnitudes in coil #1 and #2 if a short circuit is placed across coil
#2 while the given voltage is applied across coil #1? CtB'\//4\ 5133 0)) KV L OV\ RH 1002
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This note was uploaded on 01/24/2012 for the course ECE 330 taught by Professor Petersauer during the Spring '12 term at University of Illinois, Urbana Champaign.
 Spring '12
 PeterSauer

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