week 1 (chapters 1-4) Flashcards
Voltage can be defined as?
electrical pressure or electromotive force.
the amount of insulation needed for a given power line, (size of the insulator) is determined by ?
The voltage
The separation between the line conductors is affected by the amount of ?
Voltage
safe work practices and the types of tools needed are determined by the amount of ?
Voltage
Voltage is always measured between how many points?
2
7200/12470
7600/13200
12000/20800
19900/34500
these voltage ranges are common in what type of system?
Distribution system
as the _______ increases, so does the conductor separation and the amount of insulation needed.
Voltage
voltage measurements are taken from Line to _____ and Line to _______?
line-to-neutral and line-to-line
69,000…138,000…. and 500,000 are all examples of _________system voltages because they have only one reading?
Transmission
On transmission lines, why is there only one reading given?
because transmission lines do not carry a neutral, only line-to-line is taken
when can a distribution system have only one reading (no neutral)
when it is underground
Amps measure the ____ of electric current.
flow
a quantity of electrons FLOWING past a given point at a given time defines the _______?
Amp
a measurement of the amount of electricity FLOWING through a circuit is ?
Amperage
How does an amp meter give a reading?
by measuring the amount of coulombs per second flowing in a circuit, the meter tells the amperage (number of amps)
if the amperage rating for a wire is exceeded the wire will _____? this is caused by ?
Melt, added friction from the colliding electrons
why is amperage important in regards to wires?
because wires are rated for a given amount of current flow
define the ohm?
the unit of measure for electrical RESISTANCE
the resistance in a circuit is measured in____?
Ohms.
when resistance is high in a conductor, greater ______ is created, which results in _____and ______?
friction. Heat , Light
it is ______ for a current to flow through a larger diameter wire.
easier
one _____ is produced when one amp flows through one volt of potential difference.
watt
the watt is a unit of electrical ________?
power
The ______ is a unit of electrical POWER?
Watt
Volts multiplied by amps will result in?
Watts
If you have a 240 volt circuit with 10 amps of current, what is the wattage?
2,400……..( 240 x 10 )
What is the formula for calculating watts?
Volts x Amps =Watts
how many horsepower is in one watt?
746
E = I X R is the mathematical representation for?
Ohm’s Law
What does the E stand for in Ohm’s law?
Electromotive force (voltage)
What does the I stand for in Ohm’s law?
Intensity of current (amps)
What does the R stand for in Ohm’s law?
Resistance (ohms)
what three electrical properties are directly proportional to one another and what does this relationship represent?
Voltage, amperage, and resistance/ Ohm’s Law
E = I X R and Volts = Amps X Ohms,
are synonymous. True or false?
True.
what is the voltage of an electrical circuit with 5 ohms of resistance and 10 amps of current flow? how is the formula written?
E = 10 X 5 ………. E= 50 Volts
what is the current flow in a circuit energized with 240 volts and has 6 ohms or resistance? how do you write the formula?
I = 240 / 6 ………… 40 amps
what is the resistance of a 120 volt circuit with 5 amps of current flow?
R = 120 / 5 ……….. 24 ohms
what is the voltage of an electrical circuit with 10 ohms of resistance and 15 amps of current flow?
150 volts
what is the current flow in a circuit energized with 600 volts and has 50 ohms of resistance?
12 amps
what is the resistance of a 240 volt circuit with 20 amps of
12 Ohms.
the work performed when voltage and amperage is combined, measured in watts is called?
Power
Power is proportional to what two electrical properties?
voltage and amperage.
what is the formula for calculating POWER?
P = I X E
Watts = Amps X Volts
how many watts of power are being used in a 120 volt circuit drawing 15 amps?
1800 watts
what is the current flow of a 240 volt circuit that is delivering 3600 watts of power?
15 amps
what is the voltage of a circuit delivering 14,400 watts of power if the current is 2 amps?
7,200 volts
what is the voltage of a circuit with a resistance of 8 ohms and 15 amps of current flow?
120 volts
a circuit delivering 11520 watts of power with a resistance of 20 ohms would have how many volts?
480 volts
what is the voltage of a circuit delivering 240,000 watts of power with 20 amps of current?
12000 volts
what is the power delivered in a circuit that has 15 ohms of resistance and 10 amps of current flow?
1500 watts
the entire electrical system is comprised of four main elements. what are they?
Generation, transmission, distribution, substations
what are four abnormal conditions of the electrical system for which there are protections in place?
- excessive current
- abnormal voltage
- frequency deviations
- low power quality
what is the voltage produced at GENERATION?
13.8 KV (13,800 volts) to 24KV (24,000 volts)
the transmission systems are interconnected and called the ____?
Grid
generating facilities share what common purpose?
to generate power as efficiently as possible?
the original voltage produced at generation is too ____ and must be stepped _____ just outside for the purpose of long distance transmitting.
Low/ Up
dispersed micro generation occurs within the ________system?
distribution
power is transformed, metered, and redirected at a _________ ________?
transmission substation
how many reliability councils make up the North American Electric Reliability Corporation?
8 in the US and one in Canada
44 kv, 69kv, 115kv, and 138kv are all common voltages leaving a _______?
sub transmission station
what are the three primary functions of a sub station?
Change voltage from one level to another
connect/dis-connect lines or equipment
adjust voltage and current to control the flow of power
what advantage does AC power have over DC?
Ac can be transformed, DC cannot
voltage stays the same in a parallel circuit. True or false?
True. only amperage changes as the load is added or subtracted
the coils inside of and electric generator that wind around the magnet are negatively or positively charged?
negative
the outer ring of an atom having less than 7-8 electrons, identifies that atom as being what? it is called the what?
a good conductor/Valence
what dictates the size of an insulator?
voltage
what is the difference between phase-to-neutral and phase-to-ground?
nothing, they are the same thing
when two phase readings are given on distribution lines, what does the lower number represent? example (7,200/12,470)
phase-to-neutral
how do you get the second reading of a distribution voltage when only one value is known?
multiply the phase-to-neutral by 1.732 or divide the phase-to-phase by it
what dictates size of the wire/conductor
amperage
voltage is ________ if the strength of a magnet and speed at which it passes a conductor are ________?
increased/increased
what is the square root of 3? why is it important?
1.732/ use it to find unknown value in a distribution voltage system.
138,000 volts and less are _________ voltages?
230,000 and higher are ___________ voltages?
sub transmission/transmission
when a wire is built in _______ it increases the amperage rating?
strands
what is a chain reaction of electrons striking one another/
current
what is the ohm’s law formula?
E=IxR
what is the power formula?
P=IxE
the ______ is equal to that of a conductor in which a current of one amp is produced by a potential of one volt across its terminals?
ohm
