Generating Power
• Most of our power comes from large power plants that convert mechanical energy into electrical energy
• Remember that question, “why are turbines so important?” We will answer that!
Topic 6 Generators and Motors
Power Plant Turbine -> Generator
• The turbine provides enough force to turn the generator’s coil of wires
Topic 6 Generators and Motors
Electric Generator
• Device that converts mechanical energy into electric energy
Topic 6 Generators and Motors NOTES
How do we know?
• Compass needle turns when near electric field• With more electricity there is a stronger
needle deflection = stronger magnetic field
Topic 6 Generators and Motors NOTES
Topic 6 Generators and Motors NOTES
• Reverse the electric current and you reverse the direction of the magnetic field
• Stop the current = stop the magnetic field
Electromagnet
• When current is passed through a coil of wire wrapped around an iron rod an electromagnet is created
• North and south poles form on either end of the wire
• More coils = stronger magnet
Topic 6 Generators and Motors NOTES
Topic 6 Generators and Motors
Electromagnet from a soft iron core that becomes magnetic when current flows
Magnetized Material
Water has a dipole (North and South)Alignment of “poles” is similar to the alignment of charges.
Topic 6 Generators and Motors
Links
• Using iron filings to observe field of solenoid https://www.youtube.com/watch?v=CZKNl9WBIk4
• melt metal with magnets https://www.youtube.com/watch?v=8i2OVqWo9s0
• Make a Magnetic Field https://www.youtube.com/watch?v=j8XNHlV6Qxg
Topic 6 Generators and Motors
How are electricity and magnetism related?
• Electricity and magnetism related because flowing electrons produce a magnetic field.
• Electricity and magnetism are ALSO related because spinning magnets can produce electricity.
Topic 6 Generators and Motors
Electricity and magnetism are related:flowing electrons produce a magnetic fieldspinning magnets can produce electricity
• https://www.youtube.com/watch?v=d_aTC0iKO68
• Motor: – electricity -> mechanical energy
• Generator: – magnet -> mechanical force -> electricity
Topic 6 Generators and Motors
• Motor: – electricity -> mechanical energy
• Generator: – magnet -> mechanical force -> electricity
AC Generators
- External force rotates the coil- Coil of wire rotates inside of a stationary magnetic field- Most generators use electromagnets instead of permanent magnets- As coil’s wires rotate inside the field, electrons move
Topic 6 Generators and Motors
AC: Alternating Current
• AC generators produce electricity that changes directions
• After one half-rotation of the coil, each side passes near the opposite pole of the magnet, and the electrons move in the opposite direction
Topic 6 Generators and Motors
Benefits of AC current
• Easy to increase/decrease the voltage• This helps set up voltage for power line
transmission (more in Topic 7)
Topic 6 Generators and Motors