Electrical Systems Flashcards
3 things that determine the amount of current in a circuit resulting from magnetic induction:
1) Strength of the magnetic field.
2) Number of conductors passing through the field.
3) Speed with which the field is crossed.
Type of electricity produced by magnetism:
AC
The armature coils of a DC generator produce _______ electricity.
AC
A device that allows electrons to flow in one direction while preventing their flow in the opposite direction:
Rectifier
A mechanical rectifier mounted on the armature shaft of a DC generator:
Commutator
AC is rectified in a DC generator by ____ and ____.
Commutator and brushes.
In an AC generator, the brushes ride on __________ to carry current in and out of the rotor coil.
Slip rings.
An electrical current flowing through a coil of wire will produce a/an _______.
Electromagnet.
The field frame of a typical aircraft DC generator has 4 ______ wound in _______.
Field poles.
Field coils.
The _______ controls the amount of current flowing into the field coils.
Voltage regulator.
T/F
The voltage regulator determines the voltage produced by the generator.
True.
Via the strength of the magnetic field produced by the electromagnets.
DC generators are said to be _______ because of the field frame’s residual magnetism that is used when starting.
Self-excited
Residual voltage is a result of _______ and should amount to _______.
Residual magnetism.
2 volts or less.
The process to restore residual magnetism to the field frame:
Flashing the field.
How to flash the field:
A pulse of current from the battery is sent through the field coils in the direction in which current normally flows.
Types of generators:
1) Series-field generator
2) Shunt-field generator
3) Compound generator
The _________ arrangement is used for low output aircraft generators.
Shunt-field
The _______ arrangement is used for high output aircraft generators.
Compound
The coils of a practical generator are wound around a core of __________.
Laminated soft iron.
The point in the rotation at which there is no voltage or current from the ends of the coil is the ______ or _______.
Neutral position.
Neutral plane.
Required basic controls or protection devices for DC generators:
1) Current limiter
2) Voltage regulator
3) Reverse-current cutout and switch.
A type of circuit protection device (current limiter) that allows a momentary flow of excess current, but opens the circuit if the excessive flow is continued:
Slow blow fuse.
Automatic current limiters monitor output current and reduce ______ to prevent excessive generator output voltage.
Field current
What is the result of voltage being supplied to the output terminal of a DC generator?
The generator will act as a motor.
The reverse-current cutout/switch does what?
Disconnects generator from electrical system to prevent battery discharge and generator damage when gen voltage is lower than batt voltage.