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Power Requirements Definitions & Logic

Power Requirements Definitions & Logic. Use voltage range from most stringent (narrowest) customer Intersection of ranges as overall voltage range Sum total current needed for all customers plus margin Union of all max current loads (total current) Power Supply Efficiency is NOT 100%

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Power Requirements Definitions & Logic

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  1. Power Requirements Definitions & Logic • Use voltage range from most stringent (narrowest) customer • Intersection of ranges as overall voltage range • Sum total current needed for all customers plus margin • Union of all max current loads (total current) • Power Supply Efficiency is NOT 100% • Efficiency = Pout / Pin expressed as a percentage • Linear Efficiency Typically Very Low (<50%) • Switching Efficiency Typically Higher (>60%) • AC or DC Regulation Specifications • Line or Supply Regulation (DVout/DVin) expressed as a % • Load Regulation (DVout/DZload) expressed as a %

  2. Power Requirements Definitions & Logic In a student project a DC power supply (Block W) is to be designed to provide two DC power outputs to operate all the Blocks and Loads as shown below. The requirements for the DC power input for all the Blocks are summarized below. DC Power Outputs 1 & 2 Power Block X Block W AC 1KW 12V Nom Indicator Lamp Block Y Block Z • · Block X: Interfaces to 120VAC – 60Hz nominal power • · Block W: Requires 4.75 - 5.25 VDC @ 100mA Max • Block Y: Requires 11.75 – 12.25 VDC @ 50 mA Max • Block Z: Requires 4.90 – 5.10 VDC @ 200mA Max & 11.50 – 12.15 VDC @ 510mA Max What are the two DC Power output requirements that the owner of Block X should design to?

  3. Power Requirements Definitions & Logic DC Power Outputs 1 & 2 Power Block X Block W AC 1KW 12V Nom Indicator Lamp Block Y Block Z • · Block X: Interfaces to 120VAC – 60Hz nominal power • · Block W: Requires 4.75 - 5.25 VDC @ 100mA Max • Block Y: Requires 11.75 – 12.25 VDC @ 50 mA Max • Block Z: Requires 4.90 – 5.10 VDC @ 200mA Max & 11.50 – 12.15 VDC @ 510mA Max Answer: Nominal 5VDC supply: Most stringent (narrowest) voltage range = 4.90 – 5.10 VDC Max Total Current = 100mA + 200mA = 300mA Nominal 12VDC supply: Most stringent (narrowest) voltage range = 11.75 – 12.15 VDC Max Total Current = 50mA + 510mA + 12.15V/1KW = 572.15mA

  4. Introduction to Global AC Power 50 Hz, 220-240 V 50 Hz, 220-240 V 60 Hz, 120 V 50/60 Hz, 100V 50 Hz, 220-240 V 60 Hz, 110/220 V 60 Hz, 110/220 V

  5. Global Power Input Requirements • Know the Market your product is Intended to Serve ! • Min Voltage Variation = Nominal -15% to Nominal +10% • Min Global Voltage Range: 85 – 264 VAC Note: Many products relax to 100 – 240VAC • Min Frequency Variation = Nominal +/- 3 Hz • Min Global Frequency Range: 47-53Hz, 57-63 Hz Note: Many products use 47-63 Hz • Plug versions cover Types A-M • For complete global listing see World Wide Electricity Reference document

  6. COUNTRY VOLTAGE FREQUENCY PLUG COMMENTS Afghanistan 220V 50 Hz C & F * * A UN correspondent reports C and F common in Kabul, but its likely a variety of plugs may be used around the country.  Some sources report Type D also in use. Albania 220V* 50 Hz C & F *Voltage variations common Algeria 230V 50 Hz C* & F *A variation of Type C with a ground post offset about 1/2-inch from center may also be found. American Samoa 120V 60 Hz A, B, F & I Angola 220V 50 Hz C Anguilla 110V 60Hz A(maybe B) Antigua 230V* 60 Hz A & B *Airport area is reportedly Antigua power is 110V. Argentina 220V 50 Hz C & I* *Neutral and line wires are reversed from that used in Australia and elsewhere.  Click here for more. Armenia 220V 50 Hz C & F Aruba 127V* 60 Hz A, B & F *Lago Colony 115V Australia 230V* 50 Hz I *Outlets typically controlled by adjacent switch.Though nominal voltage has been officially changed to 230V, 240V is within tolerances and commonly found.  Austria 230V 50 Hz C, F Azores 220V* 50 Hz B, C, & F *Ponta Delgada 110V; to be converted to 220V For complete global listing see World Wide Electricity Reference document

  7. AC Power Quality – Standards Types A & B No Standardization, Many Types Many countries have multiple plug/receptacle types in service

  8. A typical voltage sag Voltage sags are by far the most common power disturbance AC Power Quality – Standards

  9. ANSI - American National Standards Institute IEEE - Institute of Electrical and Electronics Engineers IEC - International Electrotechnical Commission NEMA - National Electrical Manufacturers Association NFPA - National Fire Protection Association NEC - National Electric Code US Military Organizations that create power standards

  10. IEEE 1433: Power Quality Definitions • IEEE 519: Harmonic Control in Electrical Power Systems • IEEE 1159 :Monitoring Electric Power Quality • IEEE P1564: Voltage Sag Indices (Prelim) • IEEE P1453: Voltage flicker (Prelim) • IEEE P446: Emergency and standby power IEEE Power Quality Standards

  11. IEC SC77A: Low frequency EMC Phenomena • SC 77A/WG 1: Harmonics and other low-frequency disturbances • SC 77A/WG 6: Low frequency immunity tests • SC 77A/WG 2: Voltage fluctuations and other low-frequency disturbances • SC 77A/WG 8: Electromagnetic interference related to the network frequency • SC 77A/WG 9: Power Quality measurement methods • SC 77A/PT 61000-3-1: Electromagnetic Compatibility (EMC) - Part 3-1: Limits - Overview of emission standards and guides. IEC Power Quality Standards

  12. MIL-STD-1399: "Interface Standard for Shipboard Systems" covers the design and testing of electric power systems and user equipment. It applies only to shipboard power. The standard is fairly complete, covering Type I, II, and III shipboard power. It provides specifications on sags, interruptions, impulses, unbalance, and harmonics. Last revision: Notice 1, 11 Mar 1992. • MIL-STD-704E:" Interface Standard for Aircraft Electric Power "specifications for aircraft power quality, including DC, single-phase, and three-phase systems. It provides specifications on sags, interruptions, impulses, unbalance, and harmonics. Last revision: 1 May 1991. • MIL-M-24116B(SH):"Monitors, Voltage and Frequency, 400 Hz Electric Power" covers trip levels and durations of voltage and frequency monitors. It applies only to shipboard installations. • Last revision: Amendment 1, 29 October 1985. Power Quality Stds Also Exist for Military Equipment

  13. ANSI C62: Guides and standards on surge protection • ANSI C84.1: Voltage ratings for equipment & power systems • ANSI C57.110: Transformer derating for supplying non-linear loads ANSI Related Standards

  14. Diameter (mm) NEC Ampacity with60°C insulation Room Temp Amp Limits vs Solid Conductor Wire Gauges (60oC Limit) Stranded wires are calculated by calculating the equivalent cross-sectional area. AWG Diameter (in) 1 7.348 0.2893 110 2 6.543 0.2576 95 3 5.827 0.2294 85 4 5.189 0.2043 70 Wires must be treated as any Resistor in terms of voltage drop, power dissipation and thermal rise 5 4.621 0.1819 6 4.115 0.1620 55 7 3.665 0.1443 8 3.264 0.1285 40 9 2.906 0.1144 10 2.588 0.1019 30 11 2.304 0.0907 12 2.052 0.0808 20 13 1.829 0.0720 14 1.628 0.0641 15 15 1.450 0.0571 16 1.291 0.0508 12

  15. Power Input/Output Safety Devices • Grounded Plugs • Switches • Thermal 1-Time Metallic Fuses • PTC Auto-Reset-Able Fuses • PTC Inrush Current Limiters • Thermal and Magnetic Circuit Breakers • Transient Surge Protectors, Diode/SCR Clamps • EMC Line Filters • Ground Fault Circuit Interrupters – GFCI • Optical or Galvanic Isolation Signal Interfaces

  16. US NEMA 5-15 Plug and Receptacle Note that the receptacle will also accept an ungrounded plug whether polarized or unpolarized. The round earth terminal is not intended to carry current accept in failure conditions. 15 Amp Max NEMA 5-15 / CSA22.2-Nº42 The type B plug has two flat parallel pins with the same geometry as type A, and a round ground or earthing pin (American standard NEMA 5-15/Canadian CSA 22.2, Nº42). It is rated at 15 amperes. The ground pin is longer than the two parallel pins so that the device is grounded before the supply is connected. The neutral jack in the type B socket is wider to accommodate polarized type A plugs, but the type B plugs often have both pins narrow, the ground pin enforcing polarity.

  17. US NEMA 5-20 Plug and Receptacle 20 Amp Max NEMA 5-20 / CSA22.2-Nº42 The type B plug has 2 flat pins at right angels with the same geometry. The NEMA5-20R is designed to accept both ungrounded style as well as grounded 5-15 type plugs in addition to the above 5-20P.

  18. NEMA 5-20 Plug and GFCI Receptacle 20 Amp Max GFCI = Ground Fault Circuit Interrupter Senses current in ground and opens circuit if it exceed the rated value (typically 20-30mA)

  19. AC Power Efficiency – Standards

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