Motoring Flashcards
1
Q
How can we find the direction of the magnetic field around a wire?
A
Right-hand grip rule
2
Q
What happens when a wire is placed between the poles of a magnet?
A
The wire moves out of the gap when the current is switched on.
3
Q
What happens when current inside the wire when current is passed through it between two poles of a magnet?
A
- There is a force on each side of the coil
- Using Fleming’s left-hand rule you can see that the forces on either side go in the opposite direction
- This causes the coil to spin
4
Q
What makes a motor spin faster?
A
- Increased number of turns in the coil
- Increased current
- Increased strength of magnetic field
5
Q
What is the job of the commutator?
A
To make the motor continue to spin.
6
Q
Why is the force on the coil always in the same direction?
A
The direction of the current is reserved every half turn.
7
Q
Why do magnets in practical motors have curved poles to give a radical magnetic field?
A
A radical field increases the force on the coil and keeps it constant as the motor turns.
