class: center, middle # EE-362 ELECTROMECHANICAL ENERGY CONVERSION-II ## Ozan Keysan [ozan.keysan.me](http://ozan.keysan.me) Office: C-113
•
Tel: 210 7586 --- # Induction in a Coil -- ## How many ways to induce voltage? -- - ## Time variation of flux (e.g. AC excitation) -- - ## Due to conductor movement in a stationary field -- - ## Rotation (\\(\vec{B}.dA\\) changes) --- # Example in an Electric Machine --
--- # Directions -- ## - Axial -- ## - Radial -- ## - Tangential --  --- # Electric Machine Parts -- ## Rotor -- ## Stator -- ## Airgap -- ## Tooth -- ## Slot --- # Electric Machine Parts
--- # Electric Machine Parts
--- # Group Exercise -- ## Warming-up Question ### A fisherman rowing his boat on a very small lake throws his anchor into the water. ### Does the water level of the lake rise, fall, or stay the same? [Feynman Lectures](http://www.feynmanlectures.info/exercises/boat_anchor_lake.html) --- # Group Exercise: ## Design a magnetic coupling. -- ### How many different magnetic coupling designs can you find? ### You have lots of permanent magnet, Iron and Copper, but no electric source. --- # WHY 3 PHASE? (but not 2 or 5?) --
--- # WHY 3-PHASE? - # More power per unit wire length. -- - # Constant Power [Power Graphs](https://docs.google.com/spreadsheets/d/1RP-MsrHwybAG6J3CFTbdLOCTvGdIdkaWUkhRuAHPWd0/edit?usp=sharing) -- - # Rotating MMF (wait until EE362) --- # Rotating Magnetic Field !! ## The most important term for EE362 ## What is it?? -- ### [Coca-Cola Motor](https://www.youtube.com/watch?v=cIf9iPskgJs) ### [Simplest AC Motor](https://www.youtube.com/watch?v=vbh_yR9Ngc0) --- # Single Phase AC: A time varying signal # \\(I=sin(\omega t)\\)
### X-axis: Time --- # MMF created by a single coil
### If excited by DC: ## \\(MMF=F_m cos(\theta)\\) --- ## MMF created by a single coil ## What happens if the coil is excited with AC? -- ### DC excitation waveform multiplied with a time varying sinusoid: \\(sin(\omega t)\\) ## \\(MMF=F_m cos(\theta) sin(\omega t)\\) -- ## Standing wave!
---
--- # Three Phase AC
## Invented by Nicola Tesla in 1880s ### was independently invented by [Galileo Ferraris](https://en.wikipedia.org/wiki/Galileo_Ferraris), [Mikhail Dolivo-Dobrovolsky](https://en.wikipedia.org/wiki/Mikhail_Dolivo-Dobrovolsky), [Jonas Wenström](https://en.wikipedia.org/wiki/Jonas_Wenstr%C3%B6m) --- # Three Phase AC
--- # Three Phase AC: Rotating MMF
--- # Three Phase AC: Rotating MMF
--- # Let's derive it: ## Yes it is boring, but quite important. ### [Simplest AC Motor](https://www.youtube.com/watch?v=vbh_yR9Ngc0) -- #### You have three coils, seperated with \\(2 \pi/3 \\) radians and excited with 3-phase current. ## \\(I\_A (t) = I\_m cos (\omega t )\\) ## \\(I\_B (t) = I\_m cos (\omega t - 2\pi /3 )\\) ## \\(I\_C (t) = I\_m cos (\omega t - 4\pi /3)\\) --- ## \\(F\_A (t) = F\_m cos (\theta) cos (\omega t )\\) ## \\(F\_B (t) = F\_m cos (\theta - 2\pi/3) cos (\omega t )\\) ## \\(F\_C (t) = F\_m cos (\theta- 4\pi/3) cos (\omega t )\\) -- ## \\(F\_{total} (t) = F\_A + F\_B + F\_C \\) -- ## \\(F\_{total} (t) = \dfrac{3}{2}F\_m cos (\theta - \omega t) \\) --- # Rotation MMF ## \\(F\_{total} (t) = \dfrac{3}{2}F\_m cos (\theta - \omega t) \\) ### Generalized solution: -- ## N-phase ## \\(F\_{total} (t) = \dfrac{N\_{phase}}{2}F\_m cos (\theta - \omega t) \\) --- # Fundamental Idea of all AC Machines --
--- # Rotating MMF
---
---
### [Nikola Tesla vs Thomas Edison. Epic Rap Battles of History](https://www.youtube.com/watch?v=gJ1Mz7kGVf0) --- ## You can download this presentation from: [keysan.me/ee362](http://keysan.me/ee362)