Motors and Generators

Motors and Generators

• Electromagnets

• Magnet Poles

• Parts of a Basic DC Motor

• Electric Generators

• From the Power Plant to Your Home

Motors and Generators

Small DC Motor

Generator in a Hydro Plant

Geothermal GeneratorImage courtesy of DOE / NREL

Electric Turbine Generator

Electromagnets

N

S

Electromagnet ends change between north and south depending on the direction of the current.

S

N

Magnet Poles

N S

Remember that opposite poles attract and like poles repel.

If you alternate the middle magnet’s poles, it will continue to spin.

N SN SN S

This is how motors can turn!

Parts of a Basic DC Motor

N SN S

DC Source

ArmatureCommutator

Brush

Commutator

Brush

Motor: A device used to convert electric energy into mechanical energy.

PermanentMagnet

PermanentMagnet

Parts of a Small DC Motor

Armature

Commutator

PermanentMagnets

Brushes

WireConnections

Electric Generators

N SN S

Mechanical motion turns the armature which creates current.

Many DC motors can function as a generator.

Generator: A device used to convert mechanical energy into electrical energy.

From the Power Plant to Your Home

Power plants generate electricity.

Image courtesy of Sacramento Municipal Utility District

From the Power Plant to Your Home

Step up transformers increase voltage for transmission across large towers.

Increased voltage increases efficiency.

From the Power Plant to Your Home

Large towers transmit electricity over long distances.

Images courtesy of DOE / NREL

From the Power Plant to Your Home

Step down transformers reduce voltage at substations to acceptable levels for the end user.

From the Power Plant to Your Home

Electricity arrives at your home at a junction box.

Usage is measured with a meter.

Step One: Wrap the Coil

1) Sand the top half of the contact on one side

2) Sand all the way around the contact on the other side

Contact

Coil

Contact

1) Cut a 3ft section of Magnet wire

2) 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.

3) 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

Preparing Your Armature

Motors and Generators

• Electromagnets

• Magnet Poles

• Parts of a Basic DC Motor

• Electric Generators

• From the Power Plant to Your Home

Image Resources

Microsoft, Inc. (2008). Clip Art. Retrieved September 10, 2008, from http://office.microsoft.com/en-us/clipart/default.aspx

National Renewable Energy Laboratory (2008). Photographic information eXchange. Retrieved November 5, 2008, from http://www.nrel.gov/data/pix/searchpix.html

Sacramento Municipal Utility District (SMUD). (2008). Power plant [Image]. Sacramento: Sacramento Municipal Utility District.