mod 5 Flashcards
are electrical components that convert mechanical energy into electrical energy by electromagnetic induction. It supplies the needed electrical energy for the operation of most electrical equipment on aircrafts.
GENERATORS
might be supplied by a waterfall, steam, wind, gasoline or diesel engine, or an electric motor.
THE MECHANICAL ENERGY
Also known as dynamo, it is an electrical generator that creates direct current, converts the alternating current to a direct current, using a commutator; it allows the current flow in one direction only.
DC GENERATOR
Also known as alternators, it is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. In an alternator, the electrical current periodically reverses its direction.
AC GENERATOR
In 1831, he demonstrated that this, in fact, could be accomplished. This discovery is the basis for the operation of the generator.
MICHAEL FARADAY (an english scientist)
One end of a single armature coil attaches to one commutator segment, while the other end is soldered to the adjacent segment.
LAP WINDING
In a _____ lap winding, the ends of each coil are connected to adjacent commutator segments. In this way all the coils are connected in series.
SIMPLEX
In a _____ lap winding, there are in effect two separate sets of coils, each set connected in series. The two sets of coils are connected to each other only by the brushes.
DUPLEX
A _____ lap winding is in effect three separate sets of series-connected coils.
TRIPLEX
In a _____, the ends of each coil are connected to commutator segments two pole spans apart. Instead of short-circuiting a single coil, a brush will short-circuit a small group of coils in series.
WAVE WINDING
The generator’s field coils are energized or excited from an independent external dc source, such as a battery.
SEPARATELY EXCITED
When a generator supplies its own excitation; field coils are energized from the current produced by the generator itself.
SELF-EXCITED
Where the field winding in series with armature winding.
SERIES-WOUND
Where the field winding in parallel with armature winding.
SHUNT-WOUND
Combination of series and shunt winding. It is used more extensively than other types of generators because it can be designed so that it has a wide variety of characteristics.
COMPOUND-WOUND
When the shunt field is in parallel only with the armature.
SHORT-SHUNT
When the shunt field is in parallel with both the armature and series field.
LONG-SHUNT
consist of copper losses in the electric circuits and mechanical losses due to the rotation of the machine.
THE LOSSES OF GENERATORS AND MOTORS
Used to carry the field winding and poles. It is a hollow cylinder and together with the rotor constitutes the magnetic circuit or core of the machine.
STATOR
Used to carry the armature winding. It is cylindrical in shape. The armature is the load carrying member.
ROTOR
Used as a load carrying member mounted on the rotor. This winding rotates in the magnetic field set up at the stationary winding (Field winding). An _____ is a continuous winding; that is, it has no beginning or end. It is composed of a number of coils in series.
ARMATURE WINDING
An exciting system which may be an electrical winding or a permanent magnet and which is located on the stator.
FIELD WINDING
Rotates with the rotor and serves to rectify the induced voltage and the current in the armature, both of which are alternating current. The coils on the armature are terminated and interconnected through the _____ which comprises a number of bars or _____ segments which are insulated from each other.
COMMUTATOR
Conducting carbon graphite spring loaded to ride on the commutator and act as interface between the external circuit and the armature winding.
BRUSHES
