uses of the generator effect Flashcards
(5 cards)
1
Q
what is the generator effect used in?
A
- an alternator to generate ac
- a dynamo to generate dc
2
Q
explain how the generator effect is used in an alternator to generate ac
A
- alternators rotate a coil in a magnetic field
- as the coil spins, a current is induced in the coil
- two sides of coil attach to two different rings
- current changes direction every half turn
- slip rings and brushes so contacts don’t swap every half term
- means they produce an alternating pd
3
Q
explain how the generator effect is used in a dynamo to generate dc
A
- coil moves through magnetic field
- as the coil spins, a pd is induced in the coil
- complete circuit so current is induced
- current flows in the same direction
- each half-revolution, (the two halves of) the commutator switch brushess
- so the direction of the current does not reverse every half rotation
4
Q
what do alternators do?
A
rotate a coil in a magnetic field
5
Q
ac graph
A
- maximum pd when coil horizontal
- as wire sweeps directly through magnetic field lines at fastest rate
- pd falls to zero when coil is vertical
- as coil is now moving parallel to field, not cutting
- pd again as coil continues to move round
- but pd reversed direction as two sides of coil now moving in a different direction to before