USING ELECTRICITY Movement Of Electricity Flashcards
______ exist around a current carrying wire
Magnetic fields
Parts of an electric motor (4)
Commutator, field cool, brushes and rotating coil
Magnetic field uses
electric bells, electromagnets, relays
Advantages of electromagnets
Can be switched off
A current carrying wire experiences ____ when placed in a magnetic field.
Force
What does the force in a current carrying wire depend on?
The direction of the current and the magnetic field.
How would you reverse the direction of force?
Reverse directing of current/magnets
What do field coils do?
Produce a magnetic field
Rotating coils
Carry the magnetic field so that there is a force on the coil
Commutator
To ensure the motor keeps tiring in one direction in changes direction every half turn
What do brushes do?
Provide electric current with good contact
In a commercial motor what differences are there with normal electric motor?
Carbon brushes, field coils, mulstinsection commutator
Why does a commercial motor have carbon brushes
Good contact but reduced wear and withstand high temperatures.
Why does a commercial motor have field coils
Stronger
Why does a commercial motor have multiple section commutator
Smooth turning (hundreds of turns)
What is a permanent magnet?
A magnet who’s magnetic field cannot be switched on and off
_____ poles repel and _____ poles attract.
Like poles repel and unlike poles attract.
If you increase the current through the wire what happens to the strength of the magnetic field?
It increases
How can an electromagnet be made stronger?
Increasing the number of coils of the wire, increasing the current
Why would a relay be used?
When is small current circuit is used to control a switch in a high current circuit.
