The Motor Effect Flashcards
What is the motor effect?
-When a current-carrying wire (or any other conductor) is put between magnetic poles, the magnetic field around the wire interacts with the magnetic field it has been placed in
-This causes the magnet and the conductor to exert a force on each other
-This is called the motor effect and can cause the wire to move.
How does the angle between the wire and the magnetic field affect the force experienced by the wire?
-The wire experiences the full force when it is perpendicular (at 90°) to the magnetic field.
-At angles in between, the force decreases, and if the wire runs parallel to the magnetic field, it experiences no force.
Describe a practical demonstration to illustrate the direction of the force in the motor effect
-To illustrate the force direction, set up a circuit with a horseshoe magnet and a bar placed on the rails inside.
-When current flows through the rails, the bar moves due to the interaction between the magnetic fields, indicating the force direction.
What is magnetic flux density?
How many field (flux) lines there are in a region
What 3 things affect the force acting in a conductor in a magnetic field?
1)Magnetic Flux Density- This shows the strength of the magnetic field
2)The size of the current through the conductor (force increases with magnitude)
3)the length of the conductor that is in the magnetic field
What equation is used to calculate the force acting on a conductor when the current is at a 90° angle to the magnetic field it is in?
How do you use fleming’s left hand rule to find the direction of the force (motion) exerted on any carrying conductor in a magnetic field?
1)Point your First finger in the direction of the magnetic Field.(F for field)
2)Point your seCond finger in the direction of the Current. (C for current)
3)Your thuMb will then point in the direction of the force (M for Motion).
What does Fleming’s left-hand rule demonstrate?
1)If either the current or the magnetic field is reversed, the direction of the force will also be reversed.
2)This rule is applicable in scenarios like motors.
What are the forces acting on the two side arms of a coil in a basic dc motor?
1)The forces are the usual forces acting on any current in a magnetic field.
2)Due to these forces acting in opposite directions, the coil rotates because it’s on a spindle.
How can the direction of a dc motor be reversed?
By swapping the polarity of the dc supply (reversing the current) or swapping the magnetic poles over (reversing the field)
How can the speed of a dc motor be increased?
By increasing the current, adding more turns to the coil, or increasing the magnetic flux density
How do you work out the direction of a dc motor’s rotation?
Using Fleming’s left hand rule
