t7-generators and effects Flashcards
describe flemings left hand rule
-thuMb=Motion
-First finger=magnetic Field
-seCond finger=Current
what is the motor effect
a wire carrying a current in the presence of a magnetic field will experience a force
how should the wire be in relation to the magnetic field
-perpendicular
-it’ll be repelled by the permanent magnet and experience a force so it will move
how to increase speed of rotations in electric motors
-increase magnetic flux density- use more powerful magnets
-increase number of coils
-increase current
what does a split ring commutator do
-swaps positive and negative connections every 180degrees
-direction of current swaps every 180degrees
-forces acting on coil will always be in the same direction
what is the generator effect
when a wire experiences a changing magnetic field, it induces a current which creates a Potential difference
2 ways to generate electricity
-move a wire through a magnetic fields so it cuts through the magnetic flux
-move a magnet inside a coil of wire
3 ways to increase PD
-use a stronger magnet
-increase number of loops in coil
-increase speed at which the magnet is moved
what is induced current
-has a magnetic field which opposes the original change
-eg. induced field repels a magnet out of a coil when it enters a coil
how does an alternator work in a generator
1.coil rotates relative to the magnets, inducing a magnetic field which induces a voltage+current
2.slip rings+brushes stops contacts swapping every half turn
3.produces alternating PD+current
4.as coil rotates faster, peaks of oscillations get larger and more frequent
how does a dynamo work in a gernerator
1.coil rotates relative to the magnets, inducing a magnetic field which induces a voltage+current
2.split ring commutator swaps contacts every half turn
3.produce a direct current
4.as coil rotates faster, peaks of oscillations get larger and more frequent
