week 2 (chapters 5-6) Flashcards
what are some methods of generation?
steam, hydroelectric, wind, distributed generation, combustion engine.
fossil fired, nuclear fired, geothermal, and solar fired generation are all ways of producing __________ for electrical energy?
high pressure steam
what are the sources of fossil fuel generation?
coal, petroleum, natural gas
the process in which gas is harvested and fired in a combustion turbine, and the exhaust from that turbine makes steam to power a second turbine connected to a generator, is called?
combined cycle generation
what percent of todays electrical energy is produced with nuclear generation?
20%
what are the two methods of solar generation?
photovoltaic/parabolic trough
semi conducting solar panels produce power from direct sunlight in the form of DC, which is then converted
photovoltaic
heat energy from the sun heats up salt to a molten state, which passes through a boiler to make steam for electrical energy
parabolic trough
dispersed micro generation or _______________ is small scale and normally located at the point of consumption (solar panels)
distributed generation
synchronized with the electrical grid to help offset high costs of power during times of peak demand?
distributed generation
energy can be converted but in cannot be __________ or ____________
created /destroyed
energy in motion is most often seen in _________
electrical motors
what does the law of magnetic charges say?
like charges repel/opposites attract
in AC circuits, the terms positive and negative refer to _________ in a conductor?
direction of current
voltage flowing away from source is _______ and voltage flowing toward it is _________. this is known as ________
positive, negative/polarity
strength of voltage produced depends on three factors. what are they?
number of turns in the coil of wire
strength of magnet
speed at which magnetic lines of flux passes the coil
a graphical representation of what is happening to voltage in an AC circuit over time is a ?
sine wave
is the voltage of a generator that has rotated 90 deg positive or negative?
positive
what is the voltage of a generator that has rotated 180 deg?
zero
is the voltage of a generator that has rotated 270 deg negative or positive?
negative
what is the voltage of a generator that has rotated 360 deg?
zero
one rotation of a generator at 360 deg is known as one ______?
cycle
_________ is the number of times a generator rotates in one second?
frequency
frequency is measured in cycles per second, and is called ______?
hertz
60 revolutions per second is also _______? this is the standard for ______ and _______.
60 hertz/ United Utates and Canada
how do you calculate instantaneous voltage?
E(inst) = E(max) x Sine
E(inst) is the same as saying?
instantaneous voltage, voltage at any point on the waveform
E(max) is the same as saying?
maximum or peak voltage
Sine < is the?
Sine of the angle of rotation
a sine wave has a peak voltage of 7200 volts, what is the voltage after 45 deg of rotation?
use formula: E(inst) = E(max) x Sine<
E(inst) = 7200 x sine 45 deg
E(inst) = 5091.17 volts
a sine wave has a peak voltage of 7200 volts. what is the voltage after 210 deg of rotation?
use formula: E(inst) = E(max) x Sine<
E(inst) = 7200 x sine 210 deg
E(inst) = 3600 volts
DC voltage is one continuous value. it produces a constant amount of power. true or false?
true
RMS stands for ?
root mean square
the value of AC voltage that will produce the same amount of power as a like value of DC voltage?
RMS (root mean square)
RMS values are always _____ than the ______ value?
lower /peak
what is the formula to find the RMS value of a sine wave?
RMS = 0.707 x peak voltage
how do you find the peak voltage of a sine wave if only the RMS value is known?
Peak = 1.414 x RMS
a sine wave has a max voltage of 10,184 volts. what is the RMS value?
RMS = 0.707 x peak RMS = 0.707 x 10,184 RMS = 7200 volts
direct current has a _______ load?
resistive
AC circuits have three types of load which are
- resistive
- inductive
- capacitive
if the voltage and current rise and fall at the same time they are ______?
in phase
if the voltage and current rise and fall at DIFFERENT times, they are ______?
out of phase
a capacitor is added to a circuit to counter (balance out) _______ load?
inductive
inductive loads come mostly from what common piece of equipment on the line?
transformers
what is the square root of 2? ………used for what?
1.414/used to find peak voltage when RMS is known
what is the square root of .5? ……..used for what?
.707/ used to find RMS when peak voltage is known
how many times does the RMS voltage apear on a sine wave?
4
how many times does zero/no voltage appear on the sine wave?
3
why is peak voltage not used in an AC circuit?
it is the least amount of available current, only appearing 2 times on the sine wave
true power only exists when the load of an AC circuit is purely _______?
restive
