ELECTRICIAN`S MATE Quiz 06

Which of the following trip elements should NOT be used on the AQB-A250 circuit breaker?



• 
150 A

• 
300 A

• 
125 A

• 
275 A

The output of all ac generators is generated in what winding?



• 
The field winding

• 
The armature winding 

• 
The stator winding

• 
The rotor winding

What indication is given if lamp C is dim when switch S is closed?



• 
Phase C has a ground

• 
Phase B is shorted

• 
Phase A is open

• 
Phase C has a partial open

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?



• 
It simplifies the installation

• 
It reduces the weight and space requirements

• 
It reduces equipment requirements

• 
Each of the above

Which of the following conditions is most likely to cause a relay magnet to chatter?



• 
Rusty magnet sealing surfaces
• 
Open coils

• 
Burned contacts

• 
Shorted coils

You are troubleshooting a circuit and you want to know the maximum allowed current. This information is marked on which, if any, of the following plates?



• 
Distribution panel circuit information plate

• 
Distribution panel cabinet information plate

• 
Cable identification plate

• 
None of the above

Aboard ships, switchgear groups are physically separated as much as practical for what reason?



• 
To prevent accidental loss of power

• 
To prevent unnecessary weight during construction

• 
To afford greater protection from damage during battle 

• 
To allow easy access for maintenance

Selective tripping is useful aboard ship for what reason?



• 
It isolates faulty circuits without interrupting other associated circuits 

• 
It systematically opens all circuits when damage occurs

• 
It maintains overcurrents where fuses will not

• 
It allows overcurrents to flow in the circuits

What information is contained on circuit information plates located on distribution panels?



• 
The circuit number, the name of the circuit controlled, and the space served 

• 
The space served and the circuit number only

• 
The circuit number and the name of the circuit controlled only

• 
The space served, the circuit number, and the circuit power used

Which of the following is NOT a function provided by switchboards aboard ships?



• 
Control, monitoring, and protection of the ship’s service generators

• 
Automatic shifting of power to alternate sources if normal power is lost 

• 
Circuit protection

• 
Distribution of three-phase, 450-volt power

If lamp A is out when switch S is open, what problem is indicated?



• 
Lamp A is burned out

• 
Phase A is grounded

• 
Phase A is partially grounded

• 
Phases B and C are shorted

Which of the following circuit breakers must be manually operated to interrupt current flow?



• 
Type NQB

• 
Type NLB

• 
Both 1 and 2 above

• 
Type ACB

For what reason, if any, is the phase sequence important to the distribution system aboard ship?



• 
An improper phase sequence will cause voltage fluctuations

• 
The phase sequence determines the amount of current available

• 
The phase sequence determines the direction of rotation of three-phase motors 

• 
None; the phase sequence has no effect on the distribution system

A magnetic-type overload dashpot relay tends to trip before the overload current becomes excessive. How can you adjust the relay to trip at a greater current?



• 
Raise the indicating plate

• 
Lower the indicating plate

• 
Raise the plunger by turning the dashpot in a forward direction

• 
Lower the plunger by turning the dashpot in a reverse direction

Revolving armature generators are seldom used for what reason?



• 
They are more expensive to operate

• 
They are subject to arc-over at high voltages 

• 
Their output power is conducted through fixed terminals

• 
They are physically larger than other types of generators

Which, if any, of the following systems make(s) up the power distribution system?



• 
The casualty power system

• 
The emergency power system

• 
The ship’s service system

• 
All of the above

At what interval should the connections of new portable electric wiring be tested?



• 
Before being used for the first time

• 
Annually

• 
Semiannually

• 
Before every use

The instantaneous trip setting of the AQB-A250 circuit breaker is adjusted by using what components?



• 
Shunt trips

• 
Thermal studs

• 
Trip coils

• 
Adjusting wheels

While testing the power cord of a portable electric drill, you notice a fluctuation in the resistance reading. The fluctuating resistance reading indicates which of the following problems?



• 
A short

• 
A ground

• 
A faulty cable 

• 
Each of the above

What service is provided by bus transfer equipment?



• 
Prevention of overloading the generator circuit breakers

• 
Prevent paralleling of two switchboards if the voltage and current relationships are improper

• 
Short-circuit protection to the ship’s service generators

• 
Two sources of power to equipment that is vital to the ship

What is the advantage of using an MBT as an alternate power source to a vital load?



• 
The maintaining of 58% of the lighting circuits if one phase is lost

• 
Automatic switching of power supplies

• 
Circuit conditions can be met before energizing

• 
The load can be secured faster in an emergency

What is the function of the switchboard bus ties?



• 
To permit switchboards to be cross connected and to allow paralleling of generators

• 
To allow power distribution direct from the generator to the load

• 
To feed power to the dc generator

• 
To allow the generators to operate in series

What is the closing sequence of the contacts in an ACB circuit breaker?



• 
Arcing contacts and the main contacts close together

• 
The main contacts close; then the arcing contacts close

• 
Main contacts close only

• 
Arcing contacts close; then the main contacts close

When testing a grounded receptacle, what is the maximum acceptable resistance from the ground connection to the ship’s hull?



• 
1.05

• 
0.0001

• 
Less than 1

• 
1.0

What is the purpose of the disconnect links?



• 
They provide a convenient means of load testing ship’s service generators

• 
They are used to provide overcurrent protection to the main bus

• 
They provide a means of securing power to a switchboard during a fire

• 
They enable repairs to be conducted to one switchboard without affecting the operation of the whole system