Simulation things to note… Part A: your arrow tip = red part of needles Part B: you can change battery voltage on the actual battery Part C: circuit = what is on your screen, when you click on “polarity” = “flip polarity” Voltage Current Resistance

Electric Motors and Generators Chapter 17 Electric Motors and Generators

Electric Motors and Generators Electrical energy: energy from moving electrical charge Mechanical energy: energy due to motion or position Motors: transform electrical energy into mechanical energy Generators: transform mechanical energy into electrical energy

More Vocabulary Rotor – a piece that rotates in a motor Commutator – a device that can reverse the flow of electric current

Electric Motors Motors have three parts: A rotor with magnets that alternate. One or more fixed magnets around the rotor. A commutator that switches the direction of current to keep the rotor spinning.

Electric motors Around the edge of a rotor are several magnets, their alternating north and south poles facing out.

The disk is a “rotor” because it rotates. Electric motors To make the rotor spin, bring a permanent magnet close to its edge. The free magnet attracts one of the magnets in the disk and repels the next one. The disk is a “rotor” because it rotates.

Electric motors In a working electric motor, an electromagnet replaces the magnet you reversed with your fingers. As the rotor spins, a commutator reverses the direction of the current in the electromagnet.

Possible videos for motors https://www.youtube.com/watch?v=DsZCW34LktU Electromagnetic induction: https://www.youtube.com/watch?v=tC6E9J925pY

Electromagnetic Induction Electromagnetic induction: a moving magnet produces a current in a coil of wire Generators use electromagnetic induction to create electricity

Battery Run Electric Motors An electric motor that runs from batteries has the same three parts: rotating part, fixed magnets, and a commutator. The permanent magnets are on the outside, and the electromagnets turn in the rotor. Commutator Permanent magnets

Generating Electricity A generator converts mechanical energy into electrical energy using the law of induction. As long as the disk is spinning, there is a changing magnetic field through the coil and electric current is created.

Exit Question! The diagram below represents the rotor of an electric motor. To cause the rotor to turn in a counter-clockwise direction, the north pole of a magnet should be placed at position: