Chapter 18 - Motors, Generators, Transformers Flashcards
Which way do the magnetic field lines curve on a magnet?
From the north pole to the South Pole
What is true about a uniform field?
The lines of a magnetic field are parallel to each other
What does increasing the current do to the magnetic field?
Makes it stronger
What does reversing the current do to the magnetic field?
Reverses the magnetic field lines
What is an electromagnet made up of?
A coil of insulated wire wrapped around an iron core
When may electromagnets be used?
Scrapyard cranes, circuit breakers, electric bells, relays
In Fleming’s left hand rule what do the thumb, first and second finger represent?
Thumb - Thrust/movement
First - Field
Second - Current direction
How can you increase the force in the motor effect?
Current, coils, core
When is the force 0 in the motor effect?
If the wire is parallel to the magnetic field
When is the force at right angles in the motor effect?
When the wire and magnetic field are parallel
Describe the generator effect
Inducing a potential difference using a magnetic field
When is a potential difference induced in the generator effect?
When a wire cuts the lines of a magnetic field
How can you increase the potential difference induced in the generator effect?
Make the wire cut the magnetic field lines quicker
What is a simple generator made up of?
A coil that spins in a uniform magnetic field
When is the induced P.D of an AC generator at its peak?
When the sides of the coil cut directly across the magnetic field lines
