Agenda Bell Work

• Pass in Watts it all about

• Review for Quiz

• Circuit and Power Quiz

• Notes: Electric Motors and Generators

• Practice WS

• Building a DC motor

Electric Motors and Generators

May 8, 2013

►Electrical current can be generated by moving a metal wire through a magnetic field

►the wire must be part of an electrical circuit, there is no electrical current produced with a wire with open ends

►This applies both to alternating current (AC) and direct current (DC) electricity

Electrical Generators/Motors

►rotate a coil of wires through a magnetic field

►AC generator uses slip rings to transfer the current to the electrical circuit

►DC generator uses a split-ring commutator

AC vs. DC

Electrical Motors

►Uses an rotating electromagnet to convert electrical energy into mechanical energy

Electric Motor

MElectricalEnergy

MechanicalEnergy

DC MotorDC Motor

How does it work?

►The magnetic field around the wire causes it to be moved by the magnet (pushed or pulled)

►Commutator is attached so when the poles of the electromagnet meet the permanent magnet, the coil keeps turning

Model Electric Motor

Beakman MotorBeakman Motor

What do you need?What do you need?1. Electric Energy2. Coil3. Magnetic Field

1. Electric Energy2. Coil3. Magnetic Field

Electric Generator

►Use electromagnetic induction to convert mechanical energy into electrical energy

Electric Generator

GMechanicalEnergy

ElectricalEnergy

Stationary magnets - rotating magnets - electromagnetsStationary magnets - rotating magnets - electromagnets

How it works

►Mechanical energy turns to coil between a permanent magnet

►Moving wire through a magnetic field creates an electric current