AC Power Distribution Systems (Ch.3)⛔️ Flashcards
What is the function of the switchboard bus ties?
To allow power distribution direct from the generator to the load
On small ships, locating distribution panels centrally with respect to the load and feeding them directly from the generators has which of the following advantages?
Simplifies installation
Reduces weight and space requirements
Reduces equipment requirements
What information is contained in circuit information panels located on distribution panels?
The circuit number, the name of circuit controlled, space served
You are troubleshooting a circuit and you want to know the max allowed current. This information is marked on which of the following plates?
Cable identifications plate
For what reason is the phase sequence important to the distribution system aboard ship?
The phase sequence determines the direction of rotation of three phase motors
What is the advantage of using an MBT as an alternate power source to a vital load?
The load can be secured faster in an emergency
What service is provided by bus transfer equipment?
Two sources of power to equipment that is vital to the ship
Aboard ships, switchgear groups are physically separated as much as practical for what reason?
To afford greater protection from damage during battle
Which of the following is NOT a function provided by switchboards aboard ships?
Automatic shifting of power to alternate sources if normal power is lost
What is the purpose of the disconnect links?
They enable repairs to be conducted to one switchboard without affecting the operation of the whole system
If lamp A is out when S is open, what problem is indicated?
Phase A is grounded
What indication is given if lamp acid dim when switch S is closed?
Phase C has a ground
The output of all AC generators is generated in what winding?
The armature winding
Revolving armature generators are seldom used for what reason?
They are subject to arc over at high voltages
When dealing with the load rating of AC generators, what factor must be accounted for?
The internal heat the generator can withstand
Which of the following statements defines the term power factor?
The expression of the losses within the electrical distribution system
AC generator sets may be divided into what two classes?
Low speed, engine driven and high speed, turbine driven
What function is provided by AC generator excites?
DC to the load
The rotary force used to provide the rotating action in generators may be supplied by which of the following prime movers?
Each of the above
What is the magnitude of the voltage across any two phases?
Larger than the voltage across a single phase
When you use vectors to analyze AC circuits, what rotation direction represents (a) positive and (b) negative polarity?
(A)counterclockwise
(B)clockwise
In a purely capacitive circuit, what is the relationship between voltage and current?
Voltage and current are in phase
A generator is operating at 450v AC, 60hertz, supplying a load of 1000amps and 306,000 watts. What is the power factor?
?????
When the phase voltage is 100v in a delta connected AC generator, what is the line or load voltage?
173V
