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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 1 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu Engineering 43 Prob 5.80 Solution Dual-Source Complex-Power Balance
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 2 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices BackGround EE (§5.5) Consider Sinusoidal Sources of the form Alternatively Recall for a Sinusoid Complex Power Where –S ≡ Complex Power in V∙A –P ≡ Real Power in Watts –Q ≡ ReActive Power in VAR
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 3 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices BackGround EE (§5.5) Each Passive Component (R, C, L, V src, I src ) Generates it’s own Complex Power in an operating Circuit Furthermore Complex Power is Conserved, just a real power was conserved in purely resistive Circuits; i.e.: Equating Real & Imag Parts
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 4 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices R, C, L vs. P&Q Note that the passive sign Convention Applies to Complex Power a well Positive Pwr → ABSORBED or DISSIPATED Negative Pwr → SUPPLIED or GENERATED RESISTORS can only DISSIPATE Real Power per Text Eqns (5.69) & (5.71) I Rrms ≡ Current thru R V Rrms ≡ Voltage across R
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 5 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices R, C, L vs. P&Q INDUCTORS create POSITIVE ReActive (imaginary) Power per Text Eqns (5.70) & (5.72) Where –I Lrms ≡ Current thru L – V Lrms ≡ Voltage across L –X L ≡ Inductive ReActance, ωL
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 6 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices R, C, L vs. P&Q CAPACITORS create NEGATIVE ReActive (imaginary) Power per Text Eqns (5.70) & (5.72) Where –I Crms ≡ Current thru C – V Crms ≡ Voltage across C –X C ≡ Capacitive ReActance, −1/(ωC)
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 7 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices S by ShortHand Calc Alternatively Calculate S for any Component using the COMPLEX CONJUGATE of the CURRENT Thru the device Recall Conjugation for Imaginary of Phasor Values
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 8 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices S by ShortHand Calc If Then Also For Sources the Apparent Power:
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 9 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices Apparent Power Apparent Power Calculations are usually used with SOURCES, but the concept also applies to Impedance Loads Given an Impedance with Current I Z, and Voltage-Drop V Z then
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 10 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices Problem 5.80 Given Circuit Find The Power Condition for each element, the Quantity, Nature, and if the element is Absorbing/Supplying Power Note that this is SINGLE LOOP Circuit which thus has ONE Current
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 11 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 12 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 13 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 14 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 15 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices Confirm: ∑P avg = 0 Note that the Average Powers Add to ZERO as they must by conservation of Energy
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 16 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices Check ReActive Power
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 17 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 18 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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BMayer@ChabotCollege.edu ENGR-43_Prob_5-80_Dual-Src_Complex-Pwr_Solution_.pptx 19 Bruce Mayer, PE Engineering 43: Electrical Circuits & Devices
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