The Motor Effect Flashcards
What is Fleming’s left hand rule?
Flemings left hand rule is a technique used to figure out the direction of the force experienced by a current carrying wire in a magnetic field
When will a wire carrying a current experience a larger force: when it is parallel to the magnetic field, or perpendicular to the magnetic field?
To experience the full force, a current-carrying wire must be placed perpendicular to the magnetic field.
Give 4 ways to increase the strength of the motor effect.
Increase the current.
Use a coil of wire with multiple turns (or use more turns).
Add a soft iron core if you have a coil.
Use stronger magnets.
What does an electric motor do?
Electric motors use electricity to create rotational motion.
This is because a coil of wire carrying a current, placed in a magnetic field, rotates due to the motor effect.
Give 4 ways to increase the speed of rotation in an electric motor.
Increase the current in the coil.
Add more turns to the coil.
Use stronger magnets.
Add a soft iron core to the coil.
Which device is used to reverse the polarity in an electric motor?
A split ring commutator
How does a split ring commutator ensure the coil rotates in one direction?
The split-ring commutator swaps the positive and negative connections every half turn, meaning the direction of the current through the coil reverses every half turn.
This means that the forces acting on the coil will always be acting in the same direction.
This causes the coil to rotate continuously in one direction.
What is the motor effect?
The motor effect is the phenomenon that when a conductor carrying a current is placed in a magnetic field, the magnet producing the field and the conductor will exert a force on each other.
What is the formula to find the force exerted by the motor effect?
F = BIL
F = force exerted on wire
B = magnetic field strength
I = current in the wire
L = length of wire that crosses the magnetic field
