Don’t forget your project is due soon

• Project due on Friday March .

• Individually, students are to make an informational brochure explaining how electricity is produced and transported from the power plant to your house.

The rubric Again

• It clearly and accurately explains how electricity is generated (5pts)

• fully explains the role of transformers (3pts)

• explains the relative voltage and current in steps on the way to your house (3 pts)

• It clearly defines all important terms (4 pts)

• on time (5 pts) and aesthetically pleasing (5pts)

An electric current is not generated unless the magnetic field is moving relative to the copper wire, or the copper wire is moving relative to the magnetic field.

If you place a magnet and a conductor (copper wire), in a room together there will be no electric current generated.

This is because motion, from our equation for electricity, is missing!

So simple electric generators found in power plants contain, magnets and copper wire that when put into motion relative to one another create the electric current that is sent out to homes.

The major problem in electricity generation

Is where does the Motion come from

that keeps the copper wire and

magnets moving relative to one

another.

DC Electric Motors

By the end of this you need to know the 5 parts of any DC electric motor

and their function

The 5 parts

The armature

• The armature is an electromagnet that spins when in the presence of the magnetic field of a permanent magnet

Brushes and Power Source

• The power source creates current when the brushes connect it to the armature. The armature then becomes a temporary magnet and begins to spin.

The Comutator

The commutator changes the direction of the current in the armature. Alternating current electric motors don’t use commutators.

Electric Motors recap

An electric motor uses the sideways push of a magnetic field to turn a current-carrying wire loop. Electric motors use a commutator to change the direction of the current in the loop. Alternating current electric motors do not use commutators.

The stationary windings of a large electric motor. magnetic forces underlie the operation of such motors.

Michael Faraday (1791-1867) built the first electric motor and discovered magnetic induction.