SLIDE 1
2018 Lecture 10 Electricity Electricity not only transports kine@c - - PowerPoint PPT Presentation
2018 Lecture 10 Electricity Electricity not only transports kine@c - - PowerPoint PPT Presentation
GEOS 24705 / ENST 24705 / ENSC 21100 2018 Lecture 10 Electricity Electricity not only transports kine@c energy It also allows doing work more flexibly: engine and motor characteris@cs can differ Kine@c ------ (generator) ----------->
SLIDE 2
SLIDE 3
1/3 of total primary energy now goes to make electricity
total e ~ 32% transporta@on e ~ 21% turbines e ~ 23% ? (likely underes@mate of thermal efficiency) 61% through heat engine
SLIDE 4
All current use of steam: turbines spin generators to make electricity Steam turbines are choice for external combus5on All reciproca@ng engines are now internal combus5on
(with some minor excep0ons)
SLIDE 5
History of electricity technology
SLIDE 6
Image from: Wikimedia commons
Sta5c electricity discovered in ancient 5mes
Word origin: “electricity” from New La@n “electricus”, constructed (1600, Gilbert, De Magnete) from La@n electrum, “amber”, from Gr. “ilektron”
Kine%c energy à electrical energy: separate charge
Thaleus of Miletus describes 585 BC that amber rubbed with fur could aaract other objects
SLIDE 7
1660, von Guericke, electrosta@c “generator”
Images from: “The History
- f Electrosta0c Generators”
Sta5c electricity discovered in ancient 5mes
Word origin: “electricity” from New La@n “electricus”, constructed from La@n electrum, “amber”, Gilbert De Magnete, 1600
Kine%c energy à electrical energy: separate charge
1730s: Hauksbee shows that rubbing amber in a chamber containing mercury vapor causes light emission
SLIDE 8
1750s, demonstra@on of sta@c electricity discharge: “electric kiss”
Images from: “The History
- f Electrosta0c Generators”
Sta5c electricity discovered in ancient 5mes
Word origin: “electricity” from New La@n “electricus”, constructed from La@n electrum, “amber”, Gilbert De Magnete, 1600
Kine%c energy à electrical energy: separate charge
1795s: experiments with electrosta@c capacitors (store charge on metal)
SLIDE 9
Voltaic pile was stack of different metals (Zn, Cu) soaked in brine (inspired by Galvani’s accidental finding).
Images from: Wikipedia, BaFeryfacts.co.uk
Chemical reac5ons can create electric currents
Allessandro Volta – demonstrated 1791, “Voltaic pile” 1800
Chemical energy à electrical energy: metal oxidizes
SLIDE 10
Mary Shelley, 1818
Electricity enters the popular imagina5on
Allessandro Volta – demonstrated 1791, “Voltaic pile” 1800
Luigi Galvani frog experiment, 1792
SLIDE 11
How do you get useful work from electricity? Intersec@on of electricity and magne@sm allows transforma@on of electrical energy to / from work “dynamic electricity” = flow of steady current
SLIDE 12
Electric currents can create magnetic fields
https://www.youtube.com/ watch?v=V-M07N4a6-Y
Electromagnet, 1824 (Sturgeon)
SLIDE 13
Rota@ng wire in Hg, Faraday, 1830s Rota@ng electromagnet,
- Wm. Ritchie, 1833
Rota@ng electromagnet,
- Wm. Sturgeon, 1838
Revolving armature engine, Daniel Davis 1848 Reciproca@ng engine, Daniel Davis (?) 1840s DC electric fan, Edison 1898 Images from: Sparkmuseum