Generators, Motors and
How We Get Electricity
Topics
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What is electricity?
Energy Conversion
The Faraday Effect
Motor vs. Generator
AC/DC
Energy Trends - the case for Green
What is Electricity?
Electricity is energy transported by
the motion of electrons
**We do not make electricity, we
CONVERT other energy sources into
electrical energy**
Conversion is the name of the game
Energy Conversion Options for Electricity
Non-Thermal Paths
• Source to Electrical
Source
Sun
Chemical
Converter
Photovoltaic (photon to electron)
Fuel Cell
• Source to Potential/Kinetic to Mechanical to Electrical
Source
Dam
Tides
Wind
Converter
Penstocks
Machine
N/A
Kinetic to Mechanical
Turbine (water)
Turbine (air or water)
Turbine (air)
Mech to Electrical
Generator
Generator
Generator
Energy Conversion Options for Electricity
Thermal Paths
• Heat to Mechanical to Electrical
Source
Geothermal
OTEC
Heat to Mechanical
Turbine (vapor)
Turbine (vapor)
Mech to Electrical
Generator
Generator
• Stored Energy to Heat to Mechanical to Electrical
Source Reactor
Fuel
Combustor
U, Pu
Reactor
Sun
Collector*
H, H2, H3Reactor
Heat to Mechanical
Turbine (gas or vapor)
Turbine (gas or vapor)
Turbine (gas or vapor)
Turbine (gas or vapor)
* More a modifier or concentrator than a reactor
Mech to Electrical
Generator
Generator
Generator
Generator
Faraday Effect
• Faraday Effect
• Basic Concepts
• Voltage – V – Potential to Move Charge (volts)
• Current – I – Charge Movement (amperes or amps)
• Resistance – R – V = IxR (R in =ohms)
• Power – P = IxV = I2xR (watts)
Electric Motor
Electrical
Energy
M
Mechanical
Energy
DC Motor
Model Electric Motor
Beakman Motor
What do you need?
1. Electric Energy
2. Coil
3. Magnetic Field
Electric Generator
Mechanical
Energy
G
Electrical
Energy
Stationary magnets - rotating magnets - electromagnets
AC/DC
(not the band)
 Alternating Current  Direct Current
 Large-scale
generators produce
AC
 Follows sine wave
with n cycles per
second
 1, 2, 3-phase?
 US:120 V,60 Hz
 Europe: 240 V,50Hz
 Transforming ability
 Batteries,
Photovoltaics, fuel
cells, small DC
generators
 Charge in ONE
direction
 Negative, Positive
terminals
 Easy conversion AC to
DC, not DC to AC
Generator Phases
1 Phase – 2 Phase – 3 Phase…Smooth Power
110
Force Driving Motor (Red)
150
100
50
V( t )
V 1( t )
V 2( t )
0
155.563
V 3( t )
200
150
50
220
100
250
200
100
V( t )
 110 150
V 1( t )
0
0
0.005
0.01
0.015
0.02
0.025
0.03
t
0.035
50
150
V 2( t )
0.033
V 3( t )
0
V( t )
100
V 1( t )
50
V 2( t )
V 3( t )
100
 110 150
0
0
0.005
0.01
0.015
0.02
0.025
t
0.03
0.035
50
0
50
0.033
100
 110 150
0
0
Single Phase
Polyphase Systems
Two Phase
0.005
0.01
0.015
0.02
0.025
t
0.03
0.035
0.033
Three Phase
3 phases for smoother torque delivery
Where do we get our
Electricity?
• Fossil – Coal, Natural
Gas, Oil – 550 Gigawatts
(GW)
• Nuclear – 200 GW
• Hydro – 75 GW
• Geothermal – 2.3 GW
• Other Renewable –
Wind, Solar, OTEC – 13.6
GW
Energy Usage Per Capita (1999)
9
8
6
5
4
3
2
1
la
de
sh
ca
Ba
ng
Af
ri
In
di
a
na
Ch
i
o
M
ex
ic
U
.K
.
Ja
pa
n
si
a
Ru
s
ay
or
w
N
Ca
n
ad
a
0
U
SA
TOE/person-year
7
*TOE - Tons of Oil Equivalent (~40 Million Btus)
Oil Resources
Have Oil…
Saudi Arabia
Iraq
Kuwait
Iran
UAE
Venezuela
Russia
Libya
Mexico
China
Nigeria
U.S.
26%
11%
10%
9%
8%
6%
5%
3%
3%
3%
2%
2%
Use Oil…
U.S.
Japan
China
Germany
Canada
Russia
Brazil
S. Korea
France
India
Mexico
Italy
26%
7%
6%
4%
4%
3%
3%
3%
3%
3%
3%
2%
The U.S. uses more than the next 5 highest
consuming nations combined.
U.S. Renewable Energy Resource Assessment
Solar
10
12
14
Wind
14
16
16
12
10
12
14
16
18
10
2
Megajoules/m
10
12
20
22 24
14
26
26
24
22 20 18
14
16
<10
10-12
12-14
14-16
16-18
18-20
20-22
22-24
24-26
26-28
>28
Biomass
6.0-6.5 m/s
13.4-14.6 mph
6.5-70 m/s
14.6-15.7 mph
>7.0 m/s
15.7+ mph
Geothermal
Agricultural
resources & residues
Wood resources &
residues
Agricultural & wood
residues
Low inventory
o
Temperature <90C
Temperature >90C
Geopressured resources
o
Barriers to Change
US energy infrastructure is large and deeply entrenched
• 400,000+ miles of gas and oil pipelines
• 160,000+ of high voltage transmission lines
• 176,000 gasoline stations
• 1000’s of oil and gas wells drilled annually in the
US and Canada
Barriers to Change
 oil and gas are readily available as a world
commodity at low cost -- equivalent to $ 4 to 5 /
million Btu
 US coal is even more abundant and cheaper –
approximately $1/million Btu
 US electricity prices remain low relative to
other commodities
The average American family spends only 3
to 4% of their income on energy!!