Test 8 Flashcards
DC power may be constant or variable but always maintains one direction.
True
In terms of power quality, a square wave is a substantial improvement over a modified square wave.
False
Three-phase AC power is commonly used for motors because they can be more efficient and smaller than single-phase motors of the same power output.
True
Total harmonic distortion (THD) is the ratio of the sum of all harmonic components in a waveform to the fundamental frequency component.
True
A reactive load is a load that keeps voltage and current waveforms in phase.
False
An inverter is a device that converts DC power to AC power.
True
Thyristors can only be completely ON or completely OFF.
True
Pulse-width modulation (PWM) is a method of simulating waveforms by switching series device ON and OFF at high frequency and for variable lengths of time.
True
At high temperatures, an inverter may force the array from maximum power to a higher operating voltage, reducing power and current levels.
True
Interconnection standards require interactive inverters to maintain an output power factor between 0.95 leading and 0.95 lagging.
True
____ is the shape of an electrical signal that varies over time.
waveform
A(n) ____ wave is an alternating current waveform current waveform that switches between maximum positive and negative values every half period.
square
____ is the number of waveform cycles in one second.
Frequency
____ is the measure of how closely the power on an electrical circuit matches the nominal values for parameters such as voltage, current, harmonics, and power factor.
Power quality
____ are temporary undesirable voltages in an electrical circuit, ranging from a few volts to several thousand volts and lasting from a few microseconds up to a few milliseconds.
Transient voltages
Phase unbalance is the unbalance that occurs when three-phase power lines are more or less than ____° out of phase.
120
A(n) ____ module is a PV module that outputs AC power through an inverter attached in place of the normal DC junction box.
AC
A(n) _____-commutated inverter is an inverter that can internally control the activation and duration of its switching.
self
A(n) ____ is a device that transfers energy from one circuit to another through magnetic coupling.
transformer
____ are the power required to operate inverter electronics and keep the inverter in a powered state
Stand-by losses
A(n) ____ is the interval of time between the beginnings of each waveform pattern.
cycle
The ____ value is a statistical parameter representing the effective value of a waveform
root-mean-square RMS
____ perform one or more power processing and control functions in addition to inverting.
Power conditioning units PCU’s
A(n) ____ is a waveform component at an integer multiple of the fundamental waveform frequency.
harmonic
____ power is a combination of true and reactive power and is given in units of volt-amperes (VA).
Apparent
A(n) ____ inverter is an inverter whose switching devices are triggered by an external source.
line-commutated
A(n) _____ inverter circuit is a circuit that switches DC input into square wave AC output by using two pairs of switching devices.
H-bridge
A(n) ____ inverters circuit is a circuit that switches DC input into AC output by using one pair of switching devices and a center-tapped transformer.
push-pull
A(n) ____ is a device that converts AC power to DC power.
rectifier
A(n) ____ is a device that changes DC power form one voltage to another.
DC-DC converter
