Consulting Electrical Engineering

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Donald Jacobs
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1 Consulting Electrical Engineering How Your Engineering Education Applies to the Real World CalPoly - IEEE, EPI, PES May 27, 2010 Rick Miller, PE, LC, LEED-AP RNM Engineering, Inc. San Luis Obispo, CA

2 Agenda Describe consulting engineer's role in the design of power distribution and lighting systems for buildings (How your engineering education applies to the real world) Demonstrate a digital lighting control system

3 Useful Engineering Stuff Ohm s Law Fourier Analysis Three Phase 3 Boolean Logic Manchester Coding Inverse Square

4 Ohm s Law - Wire Sizing Allowable Ampacity SIZE What is the load current? AWG 60 C 75 C E = I R I = E / R I = E / Z (for AC) Z = Impedance of Load P = E I pf / / I = P / (E pf) 3/ / Lookup wire gauge in National Electrical Code (NEC) Temperature Rating of Conductor 90 C

5 Ohm s Law - Withstand Rating How much current during a short circuit? I = E / Z Z = Impedance of Source

6 Results of Arc Flash

7 Codes and Standards

8 DAPPER EasyPower EDSA ETAP Software

9 Fourier Analysis Total equals the sum of the parts

10 Graph of Fund. & 3 rd Harm.

11 Graph of Fund, 5 th & 7 th Harm.

12 Voltage Configurations Single phase, two wire Single phase, three wire, center tap Three phase, three wire, delta, ungrounded Three phase, three wire, delta, grounded Three phase, four wire, delta, center tap Three phase, four wire, wye

13 Single Phase 2 Wire 120V-1-2W 240V-1-2W N 120V A LOAD

14 Single Phase 3 Wire 240V 240/120V-1-3W 480/240V-1-3W B 120V N 120V A LOAD

15 Three Phase 3 Wire Delta 2400V-3-3W 4160V-3-3W 12470V-3-3W 240V B 240V-3-3W 480V-3-3W 240V C 240V A LOAD

16 Three Phase 3 Wire Delta B 240V-3-3W 480V-3-3W 240V 240V C 240V A LOAD

17 Three Phase 4 Wire Delta B 240 /120V-3-4W 240V 240V C 120V N 120V A LOAD

18 Three Phase 4 Wire Wye B 208Y/120V-3-4W 480Y/277V-3-4W 208V 120V N 208V 600Y/347V-3-4W 120V 120V C 208V A LOAD

19 Single Phase 3 Wire Wye 208Y/120V-3-3W N 120V 120V C 208V A LOAD

20 Three Phase 4 Wire Wye B 208V 120V N 208V 120V 120V C 208V A

21 Three Phase 4 Wire Wye N 120V 120V C 208V A

22 Three Phase 4 Wire Wye N 120V V C A 208V

23 Three Phase 4 Wire Wye N C 120V V A 208V

24 High School Geometry triangle Hypotenuse =1 Short leg = 1/2 Long leg = 3/2

25 High School Geometry triangle Hypotenuse =1 Short leg = 1/2 Long leg = 3/2 C 120V V 3/2 N 120V?V 2x120V 3/2 120V 3 120V x V A

26 3 Three phase wye P = IA VAN + IB VBN + IC VCN = 3 I VLN = I 3 VLN = I 3 VLL P = I 3 * 120v = I 3 * 208v P = I 3 * 277v = I 3 * 480v P = I 3 * 7200v = I 3 * 12470v triangle Hypotenuse to long leg: 1 to ½ 3

27 How to Calculate Power Power = Volts x Amps [DC] Power = Volts x Amps x PF [AC] Power = VA x PF VA = V x A [single phase] VA = 3 x VLL x A [three phase] P = VA/dt

28 Graph of Volts, Amps, Watts

29 Three Phase Power 3 phase = phase A + phase B + phase C VA = VAN x AA + VBN x AB + VCN x AC If VAN=VBN=VCN and AA=AB=AC Then VA = 3 x VLN x A VA = 3 x VLL x A [three phase]

30 How to Calculate Energy Energy = Power X Time WH = W x Hr [for a constant load] WH = Wt/dt [for a time variant load]

31 And Or Nor Xor Not If, then, otherwise Boolean Logic

32 Manchester Coding No DC component Direction of the mid-bit transition Used in Ethernet and DALI

33 Cosine Inverse Square E p and Intensity can be related

34 Let the Computer to it The angles (θ,ψ) are from distances x, y, and z

35 AND DON T FORGET

36 And Don t Forget Communication Skills Law Politics Economics Environment Continuing Education

37 Verbal Written Graphic Communication Skills

38 Law License - PE Codes Standards Insurance - professional E and O

39 History People Objective Point of View Politics

40 Economics Cost of development Cost to manufacture Life cycle Margin, mark up, profit ROI Payback

41 Environment Pollution spill containment, air quality, carbon footprint Energy saving = Power reduction X Time reduction

42 Continuing Education Magazines Journals Seminars Webinars Trade Shows Professional Societies

43 DALI Demonstration DALI: Digital Addressable Lighting Interface a digital lighting control system

44 DALI Demonstration Power Supply 120V Green White Black Purple Purple G N H DA DA DALI Dim Ballast Ground ballast case RED RED YEL YEL BLUE BLUE Dimmer Push button Requires Rapid Start Lampholders

45 DALI Demonstration Class 1 Wiring 120 V Purple Purple DALI Ballast DALI Ballast Class 2 Wiring DALI Bus Power Supply DOSI-120-D Class 1 Wiring DALI Bus DALI Ballast DALI Ballast Group Scene Controller CX Scene Controller Relay Module Occupancy Sensor Photo Sensor Class 2 Wiring 45

46 END

Applied Lighting Controls

Better Buildings By Design 2010 Applied Lighting Controls Steven Mesh, LC, IESNA Senior Lighting Program Coordinator Pacific Energy Center (Pacific Gas & Electric) 851 Howard Street, San Francisco, CA