1. Motors and Generators Magic of Electrons
© 2011 Project Lead The Way, Inc.

2. Motors and Generators Electromagnets Magnet Poles
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Motors and Generators
Electromagnets
Magnet Poles
Parts of a Basic DC Motor
Electric Generators
From the Power Plant to Your Home

3. Motors and Generators Small DC Motor Geothermal Generator
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Motors and Generators
Small DC Motor
Image courtesy of DOE / NREL
Geothermal Generator
The hydro plant generator is an image from the Grand Coulee dam.
This geothermal plant is located in southeastern California.
The electric turbine is the type that might be powered by burning natural gas.
Generator in a Hydro Plant
Electric Turbine Generator

4. Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Electromagnets S N S
Electromagnet ends change between north and south depending on the direction of the current. N

5. This is how motors can turn!
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Magnet Poles
Remember that opposite poles attract and like poles repel.
If you alternate the middle magnet’s poles, it will continue to spin. N N N S N S S S
This is how motors can turn!

6. Parts of a Basic DC Motor
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Parts of a Basic DC Motor
Motor: A device used to convert electric energy into mechanical energy.
Brush
DC Source
Commutator
Armature
Permanent
Magnet
DC Source: Provides electric current.
Permanent Magnets: Also known as field magnets, these magnets provide the magnetic field for the motor.
Brushes: Transfer power from the source to the slip rings.
Commutator: Also known as a slip rings. Transfer the power from the DC source to the armature. The design of the slip rings are what allow the current to reverse direction. The current reversing direction causes the electromagnet to reverse polarity. This can clearly be seen in the animation.
Armature: The electromagnet that spins to create rotary motion. N N S S
Permanent
Magnet
Commutator
Brush

7. Parts of a Small DC Motor
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Parts of a Small DC Motor
Brushes
Wire
Connections
Permanent
Magnets
Armature
Commutator

8. Electric Generators N N S S
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Electric Generators
Generator: A device used to convert mechanical energy into electrical energy.
Mechanical motion turns the armature which creates current.
Many DC motors can function as a generator. N N S S

9. From the Power Plant to Your Home
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Most electricity is produced using turbines. Turbines spin to create electricity. Usually turbines are turned using hot pressurized steam. Turbines are also often turned by wind or water pressure behind dams.
Image courtesy of Sacramento Municipal Utility District
Power plants generate electricity.

10. From the Power Plant to Your Home
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Generally the transformers at a power plant step up the voltage, whereas transformers at substations and on utility poles generally step down voltage. Power may be stepped down two to three times before it reaches buildings and homes.
The higher voltage increases efficiency because there is less heat loss.
Step up transformers increase voltage for transmission across large towers.
Increased voltage increases efficiency.

11. From the Power Plant to Your Home
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Large towers transmit electricity over long distances.
Images courtesy of DOE / NREL

12. From the Power Plant to Your Home
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Step down transformers reduce voltage at substations to acceptable levels for the end user.

13. From the Power Plant to Your Home
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
From the Power Plant to Your Home
Electricity arrives at your home at a junction box.
Usage is measured with a meter.

14. Preparing Your Armature
Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Preparing Your Armature
Step One: Wrap the Coil
Cut a 3ft section of Magnet wire
Start coiling the wire 3” from the end of end of the wire. Wrap the wire around a 1”diameter dowel rod until a 3” length remains.
Carefully hold the coil together and pull it off of the dowel rod. Wrap the coil with the 3” lengths you had left at the beginning and end of your coil.
Step Two: Sand the Contacts
Coil
Contact
Contact
1) Sand the top half of the contact on one side
2) Sand all the way around the contact on the other side

15. Motors and Generators Electromagnets Magnet Poles
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Motors and Generators
Electromagnets
Magnet Poles
Parts of a Basic DC Motor
Electric Generators
From the Power Plant to Your Home

16. Motors and Generators
PLTW Gateway
Unit 6 – Lesson 6.1 – What is Electricity?
Image Resources
Microsoft, Inc. (2008). Clip Art. Retrieved September 10, 2008, from
National Renewable Energy Laboratory (2008). Photographic information eXchange. Retrieved November 5, 2008, from
Sacramento Municipal Utility District (SMUD). (2008). Power plant [Image]. Sacramento: Sacramento Municipal Utility District.