3rd Six Month Final Exam Flashcards
What is the purpose of auxiliary contacts?
To protect the main contacts from burning by closing first and opening last
When is the breaker trip -free?
When it’s close to a fault
How long does the reactivation process take?
Same amount of time as the compressor has running to recharge the receiver
How is The air breaker operation dried ?
Conducting the air up through an automatic drying system
What is the purpose for the SF6 gas in a air-blast circuit breaker?
Insulate the support column current
3.059
Electrical energy per unit of charge is measured in
Volts
The radar which work is done is called ______ it is measured in ______
Power ; foot-pound pounds per second
The force of gravity on an object is its _____ the measure of how much matter is in an object is its _______
Weight ; mass
Surface roughness is measured in ?
Microinches
Potential difference is the difference in electrical_______ between two places
Potential energy
A temperature at which some physical event occurs is called _____ temperature
Critical
Whenever a circuit, which is current current is open
The current tends to continue to flow across the contacts as they separate
In a HVDC transmission system ?
The quantity and direction of power flow may be controlled with high accuracy and extreme rapidity?
Transformers have only one winding are called ?
Autotransformers
A single phase transformer may have an ?
Air core
Eddie currents are circulating current that cause
A loss of energy
Which of the below statements does not correctly describe a means or method for quenching an arc ?
Reducing the reluctance across the contacts
A power transformer, transfers, energy power from one circuit at a certain frequency and voltage and to a second circuit at
A different voltage and same frequency
Circuit breaker the Arc is normally quenched
By increasing the resistance across the contacts
Suspension type insulators
All three
A transformer developed 120 Volts in its secondary when a 2400 V source was connected across the primary assuming a primary 25 amperes secondary current is
500 amps
Electrostatic and electromagnetic unbalanced between phases in a three phase transmission line is reduced by
Transposing or rotating the conductor
All protective relaying may be classified according to the
Function they perform
Transmission lines losses due to corona may be reduced by all of the below, except ?
Increasing voltages value
The conservator system is used on transformers oil
Preserve the dielectric strength of the transformer oil
A fast realistic circuit breaker opening operation (Art out time ) would be ?
Three to four cycles
A three phase 138 KV circuit breaker can interrupt 12,000 A. What is this interrupting capacity in MVA
1656 MVA
A blowout coil would most likely be found in ?
An air magnetic circuit breaker
The high dialectic strength of gas such as SF6 under static conditions is maintained by ?
Pressurizing
In a energize transformer, iron losses are present, even if there is no load on the secondary
True
Disconnect which are commonly used on 440 or higher vote circuit to ?
Isolate or to ground electrical equipment or circuits not in service
A three phase 138 KV circuit breaker can’t interrupt 12,000 A. What is this interrupting capacity in MVA
1656 MVA
Transformers are classified as static AC machines ?
True
Of the following statements concerning mercury control, switches the one which is most nearly not correct is
They are generally used only where the circuit voltage is 120 or less
The primary reason for not replacing a blown fuse with a piece of copper wire is because ?
The desire circuit protection against overload may loss
The barricaded tape used to keep personnel out of an area where hazardous electrical work is being performed should be
Displayed at a readily visible level
The most important consideration and selecting a mold case circuit breaker is ?
Potential difference
If a person is a victim of electrical shock, your immediate action should be to ?
Ensure that breathing and circulation are maintain
The first step in locking out power to a piece of equipment is to ?
Notify the operator
What tool is intended to be used to verify that a circuit has been de-energize
Voltage tester
The NEC defines a qualified person as someone who ?
Is familiar with the equipment operations and hazards
If a victim of electric shock is unconscious, you should ?
Check for breathing and a pulse
The code on the back of a sanding belt indicates ________ of the sandpaper
Grade of grit
The blade motion of a reciprocating saw is ?
Back-and-forth in line with the motor
When drilling with a diamond - aggregate core bit , you must use a special rotary hammer and a _____
Stand
Examples of template routing include
Hinge - butt mortises
When using an electric hammer always wear ?
Safety glasses
You can prevent electric shock from power cords by ?
Grounding them 
We should never be removed from a three-prong plug ?
Grounding prong
