Show:
AC Gennies
AC Motors
DC Gennies
DC Motors
Trivia
100
The voltage generated in the armature can be connected directly to the load.
Why are high-voltage generators are usually of the rotating field type?
100
A winding that is made up of heavy copper bars connected together at each end by a metal ring made of copper or brass.
What is a squirrel cage rotor?
100
The process by which a DC voltage output is taken from an armature that has an AC voltage induced in it.
Why is Communtation?
100
The energy required to reduce the residual flux of a material to zero. The area enclosed by the Hysteresis Loop is a measure of the energy wasted (converted to heat) in magnetizing and demagnetizing a material.
What is 'coercive force' and 'hysterisis loss'?
100
TINA TURNER Clue: Film
Which singer joined Mel Gibson in the movie Mad Max: Beyond The Thunderdome?
200
Since the voltage applied to the rotating field is low voltage DC, the problem of high voltage arc-over at the slip rings does not exist.
Why is there no problem of voltage arc-over in an rotating field AC generator?
200
Since the auxiliary winding is only a light winding, the motor does not develop sufficient torque to start heavy loads.
Why can't a split-phase induction motor drive heavy loads?
200
The polarity of an electromagnet is found by using the Right Hand Grasp Rule.
How can the polarity of an electromagnet be determined?
200
They are placed between the main field poles of a generator to counteract some of the effects of field distortion.
What are interpoles?
200
TEN Clue: Think Sea
How many tentacles does a squid have?
300
I. Their terminal voltages must be equal II. Equal frequency III. Phase voltages in proper phase relation
What are the three requirements for generator parallel operation?
300
Unlike polyphase induction motors, the stator field it simply alternates polarity between poles as the AC voltage changes polarity.
Describe the stator field in a single phase induction motor.
300
When a generator delivers current to a load, the armature current creates a magnetic force that opposes the rotation of the armature.
What is motor reaction?
300
The tendency of a force to produce rotation.
What is torque.
300
SUGAR Clue: Most common use for Sugar
What is converted into alcohol during brewing?
400
Delta or Star (Y) connection.
What is the 2 methods of connecting an AC Generator to a load?
400
When ac is applied to the stator, a high-speed rotating magnetic field appears immediately which rushes past the rotor poles so quickly that the rotor does not have a chance to get started as it is repelled first in one direction and then the other.
Why can't 3-phase induction motors be started by the application of a 3-phase supply?
400
A decrease in load causes the output voltage to increases accordingly, and a larger current flows in the armature windings and the lR drop in the armature increases. This action is cumulative, so the output voltage continues to rise to a point called field saturation, after which there is no further increase in output voltage.
Explain what would happen to the output voltage of an unregulated DC shunt wound generator if the load current decreases.
400
This type of motor will run at high speed when it has a light load and at low speed with a heavy load. If the load is removed entirely, the motor may operate at such a high speed that the armature will fly apart.
What is a series DC motor?
400
HERMAPHRODITE Clue: Think general
What is the word used to describe an animal/plant that is both male and female?
500
The faster the speed of rotation, the higher the output frequency, and vice-versa. Also the more poles there are on the rotor; the higher the frequency is for a given speed.
How does speed of the rotor affect the AC generator output frequency?
500
The speed of the rotating field.
What is synchronous speed?
500
Current flowing through the armature sets up electromagnetic fields in the windings. These new fields tend to distort or bend the magnetic flux between the poles of the generator from a straight line path. Since armature current increases with load, the distortion becomes greater with an increase in load.
What is armature reaction?
500
Often used in aircraft as engine starters and for raising and lowering landing gear, cowl flaps, and wing flaps.
What is a series DC motor used for on aircraft?
500
LIVE AND LET DIE (1973) Clue: actors first Bond film
In which film did Roger Moore first play James Bond?