What is a rotating coil?
A rotating coil. Page 1. A rotating coil. Consider a rectangular coil positioned in a magnetic field (Figure 20). If the coil is rotated to different orientations relative to the direction of the magnetic field, the magnetic flux linkage through the coil changes.
What causes a coil to rotate?
A coil of wire becomes an electromagnet when current passes through it. The electromagnet interacts with a permanent magnet, causing the coil to spin.
Which way will the coil rotate?
anti-clockwise
Explaining an electric motor the coil rotates anti-clockwise because of the forces described above.
What happens when a coil is rotated in a magnetic field?
As the coil rotates in the magnetic field, the induction flux through the coil changes and a time–varying current is induced in the coil. If an electric current passes through a coil, it generates a magnetic field around the coil. The magnetic flux of this field is proportional to the induced current.
What would happen if the coil was rotated faster?
The faster the coil rotates the faster will it cut the magnetic field and the bigger will be the output voltage.
How do you calculate induced emf on a rotating coil?
Section Summary
- An electric generator rotates a coil in a magnetic field, inducing an emf given as a function of time by. emf=2Bℓvsinωt emf = 2 B ℓ v sin , where A is the area of an N-turn coil rotated at a constant angular velocity ω in a uniform magnetic field B.
- The peak emf emf0 of a generator is. emf0 = NABω
What makes a coil spin faster?
The speed of the motor can be increased by: increasing the strength of the magnetic field. increasing the current flowing through the coil.
Why does the coil spin when the switch is closed?
How does it work? The motor is connected to a battery. When the switch is closed, the current starts to flow and the coil becomes an electromagnet. In this case the current is flowing anticlockwise in the top of the coil.
What are needed to make the coil rotate continuously?
When the coil is vertical, it moves parallel to the magnetic field, producing no force. This would tend to make the motor come to a stop, but two features allow the coil to continue rotating: the momentum of the motor carries it on round a little. a split ring commutator changes the current direction every half turn.
Does the coil continue to rotate when the current is off?
When you give the coil a spin, since one side of the wire is insulated, you break the circuit briefly, so the coil continues to rotate using its momentum. When the circuit is complete again, the magnetic field once again repels the coil, so it keeps spinning. The motor can continue to spin until the battery is dead!
What happens when the coil rotates?
As the magnet spins, the magnetic field around the top and bottom of the coil constantly changes between a north and a south pole. This rotational movement of the magnetic field results in an alternating emf being induced into the coil as defined by Faraday’s law of electromagnetic induction.
Where is the magnetic force the strongest?
the poles
It is strongest at the poles. So, what are magnetic poles? Magnetic poles are opposite ends of a magnet where the magnetic field is strongest.