AKS 10C Electromagnets, Motors, and Generators

Motors and Generators

Multiple Choice

What is an electromagnet?

• A permanent magnet that retains its magnetism

• A type of magnet that is created by an electric current

• A magnet that is made from natural materials

• A magnet that does not require electricity to function

Multiple Choice

Which of the following is a component of an electromagnet?

• A wooden core

• A copper wire coil

• A plastic casing

• A rubber band

Electromagnets are made of a conductive wire, a conductive metal core, and a battery.

If the core is not a conductive metal, the electromagnet will not create a magnetic field.

The coil creates the magnetic field when attached to the battery. More loops = stronger magnetic field.

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Components of an Electromagnet:

Multiple Choice

Describe the role of the coil in an electromagnet.

• The coil is used to store energy.

• The coil is used to conduct electricity and create a magnetic field.

• The coil is used to insulate the magnet.

• The coil is used to cool down the magnet.

Multiple Choice

Explain how the core material affects the strength of an electromagnet.

• The core material does not affect the strength of an electromagnet.

• A non-magnetic core increases the strength of an electromagnet.

• A magnetic core, like iron, increases the strength of an electromagnet.

• A plastic core is the best for increasing strength.

​When the wire is connected to both the positive and negative ends of the battery, electricity flows through the wire.

This flow of negative particles turns the metal core into a magnet.

When the wire is disconnected, the metal stops acting like a magnet.

How an Electromagnet Works

Multiple Choice

What happens to an electromagnet when the electric current is turned off?

• It becomes a permanent magnet.

• It loses its magnetism.

• It becomes stronger.

• It changes its polarity.

Multiple Choice

How can the strength of an electromagnet be increased?

• By decreasing the number of turns in the coil

• By using a non-magnetic core

• By increasing the electric current

• By using a thinner wire

Multiple Choice

Which factor affects the strength of an electromagnet?

• The color of the wire

• The number of turns in the coil

• The shape of the core

• The type of battery used

Multiple Choice

How does increasing the electric current affect an electromagnet?

• It decreases the strength of the electromagnet.

• It has no effect on the electromagnet.

• It increases the strength of the electromagnet.

• It changes the polarity of the electromagnet.

Motors: Electrical Energy Mechanical Energy

• Electrical energy is used to create a current in an armature (the coil)

• The armature is in a magnetic field and has its own magnetic field due to the current flowing through it

• The armature turns so that its magnetic field lines up with the magnetic field of the magnet

• A moving magnetic field causes a voltage to be created/induced

• If there is a complete circuit, this voltage will result in a current flowing

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Electromagnetic Induction

• N pole into the coil = positive voltage induced

• Magnet at rest in coil = no voltage induced (because magnetic field isn't changing!)

• Move magnet backwards out of coil = negative voltage induced

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Electromagnetic Induction

​Generators typically produce alternating current (AC)

1. Using a stronger/bigger magnet

2. ​Moving the magnetic field faster

3. More windings/loops in the coil

​

Induced voltage can be increased by...

Generators: Mechanical Energy Electrical Energy

• Mechanical energy is used to turn a rotor attached to an armature (coil)

• The armature is in a magnetic field

• As the wire is turned, it experiences a changing magnetic field

• This results in a voltage and current

• Input: Electrical energy (battery)

• Output: Mechanical energy (coil turns)

• Motor parts: battery

Motors only

• ​Input: Mechanical energy (turn the coil)

• Output: Electrical energy (voltage and current)

• Motor parts: device to be powered

​​Generators only

Parts:

Magnet

Armature

Both

Multiple Choice

Generators are devices that convert _____ energy into _____ energy.

• chemical; mechanical

• mechanical; electrical

• electrical; mechanical

• potential; kinetic

Multiple Choice

What device is made of coils of wire with an electrical current passing through it in order to generate a magnetic field?  

• Electromagnet 

• Generator

• Electron Magnet 

• Motor

Multiple Choice

Electric motors are devices that convert _____ energy into  _____ energy.

• electrical; mechanical

• mechanical; electrical

• chemical; potential

• mechanical; kinetic

Multiple Choice

What two forces are required for generators and electric motors to work?

• magnetism and thermal

• electricity and thermal

• electricity and magnetism

• magnetism and radiant

Multiple Choice

The voltmeter is at 0 in this image. How would you manipulate the experiment to create electricity (measured in volts)?

• Flip the magnet around so the North pole is facing out
• Move the magnet back and forth
• Take the magnet out
• Add more coils around the paper cylinder

Multiple Choice

How could the experimenter increase the amount of electricity being induced by this experiment?

• Increase the number of coils

• Decrease the number of coils

• Flip the magnet around

• Nothing, the amount of electricity cannot be increased

Electromagnet

Electromagnet

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil.

electric ------> magnet

Electromagnet is a temporary magnet.

The temporary means the magnet field will appear, if a current flows through the coil.

Multiple Choice

What is an electromagnet?

• a temporary magnet made from current carrying wire around a magnetic metal core.
• a permanent magnet with a north and south pole

Multiple Choice

How are electromagnets different from magnets?

• magnets have a North and South pole

• you can turn an electromagnet on/off

• magnets are more powerful

Electromagnet components

Battery provides the energy or the power source to run the electromagnet.

The wire provides the pathway to carry electricity from component to component.

The magnetic material core becomes a temporary magnet when electricity is flowing through the circuit.

Multiple Choice

Which component provides the energy or the power source to run the electromagnet?

• Iron nail

• wire

• Switch

• Battery

Multiple Choice

What component provides the pathway to carry electricity from component to component?

• battery

• wire

• switch

• iron nail

Multiple Choice

What component becomes a temporary magnet when electricity is flowing through the circuit?

• iron nail

• copper wire

• battery

• switch

Electromagnet

The magnetic field will stronger if:

The electric current increase.

The number of turn of coil increase.

The magnetic field of electromagnet is also depend on the core.

If we put the iron (magnetic material) inside the core the electromagnet will stonger than we left the core with only the air.

Multiple Choice

What would increase the strength of an electromagnet?

• Increasing the amount of current flowing through the wire.
• Inserting a wooden core inside the coil
• Changing the direction of the current
• Decreasing the number of coils of wire

Electric generator

 The electric generator is a device that converts mechanical energy into electrical energy.

magnet ---> electric

First phenomena founded by Micheal Faraday

Multiple Choice

What is the device which converts mechanical energy to electrical energy?

• electric generator

• electric motor