Self tests Flashcards
What three quantities affect the magnitude of an induced emf?
field flux density
active length of the conductor
velocity of the conductor relative to the magnetic field
Define the active length of the conductor?
Is the portion of the conductor that actually cuts through flux lines
Purpose of the field rheostat placed in series with a generators field windings?
rheostat varies the generated voltage by varying the current through the field coils, which in turn varies the flux density of the field
What is meant by the electromagnetic term prime mover?
Device supplying energy to the generator
To increase the field flux density in a generator, would the resistance of the field rheostat have to be increased or decreased?
decreased
Which of the three factors affecting the magnitude of an induced voltage is most commonly used to control the emf?
Flux density
What is the device that supplies mechanical energy to the alternator called?
Prime mover
What is the name given to a current that periodically changes in both magnitude and direction?
Alternating Current
What is the term that represents the distance from one point on a waveform to where it repeats itself?
Cycle
As the speed of the prime mover increases, what happens to the frequency of the alternating current?
It increases
How many electrical degrees are there in each complete cycle?
360 degrees
In fleming’s left-hand rule, what does the thumb represent?
Thrust of the conductor
In fleming’s left-hand rule, what does the first finger represent?
direction of magnetic flux lines
