physics lesson 3 Flashcards
(28 cards)
Electromagnetism:
Electric current creates a magnetic field.
Moving a wire through a magnetic field creates (induces) an electric current.
This principle is used in both motors and generators.
Electrical Energy
from moving charges.
Mechanical energy
from motion or position (kinetic + potential).
Motors
turn electrical energy into mechanical energy.
Generators
turn mechanical energy into electrical energy.
Armature:
rotating coil and shaft.
Commutator
reverses current direction every half turn.
Brushes
provide contact for current to flow.
Magnets
create magnetic field
A current in the coil
makes a magnetic field → interacts with magnets → spins the coil → creates motion.
Generator Function:
Same parts as motors but no power source.
Mechanical energy spins the coil → coil moves through magnetic field → current is produced (induced).
Used in wind turbines, water dams, etc.
AC Electron Flow
Back and forth
DC Electron flow
One direction
DC Magnetic Field
Constant
AC Magnetic Field
Changing
AC Commutator Type
Slip ring
DC Commutator Type
Slip ring
AC is Used In
Homes, power grids
DC is Used In
Batteries, small devices
AC pros
Can change voltage, good for long distances
DC pros
Simple, steady current
AC cons
More complex
DC cons
Loses energy over long distances
Increasing Energy Output:
Use more coils, Spin faster, Use stronger magnets, Add an iron core to the coils
