Motors and Generators

Electricity, Magnetism and Motion

Energy and Motion

• What you know:

• 1. Magnetic force can produce motion. For example, magnets move together or apart when they are close.

• 2. An electric current in a wire produces a magnetic field. So, a magnet can move a wire with a current, just as it would move another magnet

Energy and Motion

• The ability to move an object over a distance is called energy.

• 
  

• 
  

Multiple Choice

What do you think is the energy associated with electric currents?

• Thermal energy

• Electrical energy

• Mechanical energy

• Radiant energy

Energy Transformation

• Energy can be transformed from one form into another

• When a wire with a current is placed in a magnetic field, electrical energy is transformed into mechanical energy

Multiple Choice

When a wire with a current is placed in a magnetic field, electrical energy can be transformed into..

• Chemical energy

• Mechanical Energy

• Radiant Energy

• Thermal Energy

Electric Motors

• An electric motor is a device that uses an electric current to turn an axle

• An electric motor transforms electrical energy into mechanical energy that is used to do work

• Examples of electric motors occur in many household items such as washing machines and blenders

Generators

• An electric generator is a device that transforms mechanical energy into electrical energy

• A generator uses motion in a magnetic field to produce current

• Most of the electrical energy we use comes from generators

Multiple Choice

What must happen for an action to be considered work?

• force applied & energy created
• force applied & distance moved
• force applied & matter destroyed
• force applied & mass increased

Multiple Choice

When John plugs in a toy and turns it on, a marble is carried up to the top of a slide. At the top, a marble is released and it goes down a slide. What kind of energy transformation occurs to make this toy work?

• chemical to heat
• electrical to chemical
• sound to electrical
• electrical to mechanical

Multiple Choice

Electric motors are devices that convert _____ energy into  _____ energy.

• electrical; mechanical
• mechanical; electrical
• chemical; potential
• mechanical; kinetic

Multiple Choice

Generators are devices that convert _____ energy into _____ energy.

• chemical; mechanical
• mechanical; electrical
• electrical; mechanical
• potential; kinetic

Multiple Choice

What is the device seen here?

• generator
• electric motor
• electromagnet
• magnet

Multiple Choice

What is formed when a wire in an electric circuit is wrapped around an iron core producing a magnetic field?

• electromagnet
• generator
• magnet
• electric motor