Electrical Theory Final S6

Optical fiber cable is tested in accordance to UL_______.

1651

The minimum bending radius for category 5 cable is _____ times the diameter of the cable.

4

is generally used to examine the fiber optic connection for possible problems.

A microscope

The plans for commercial PV projects usually have to be submitted to the _____ for review and comment prior to issuance of a permit.

AHJ

_____ are susceptible to interference from ac power lines.

X10 modules

Ampacity correction for _____ temperature must be considered for both the dc and ac system conductors.

ambient

One advantage of PLCs is that any input can be assigned ______ contact(s).

any number of

A _____________ converts an Alternating current power source to a Direct current power source.

Inverter

Size 2 ______ empty conduit is used for later home automation wiring

PVC

Common telephone jack is referred to

RJ11

Ethernet plug is referred to

RJ45

PLCs were first used by the __________ industry in the late 1960s.

automotive

Wires are twisted in order to

avoid interference

Zigbee consists of Coordinator Router and __________.

end devices

The installation of utility interactive solar photovoltaic systems has accelerated in recent years due to energy conservation and _____ concerns.

environmental

Factors that have recently made photovoltaic systems very popular include ______ .

environmental concerns with the use of fossil fuels and concern over dependence on foreign sources of energy

The four functions for GFP in utility interactive PV system are detect, interrupt, _____and ,______.

indicate, disconnect

One way to deal with harmonic problems is to install a _____ neutral conductor.

larger

The phasor rotation of a negative harmonic causes an induction motor to produce _____.

less torque

The LED changes electrical signal into a ____________ signal

light

LASER stands for:

light amplification by stimulated emission of radiation

The ______ is used to program the CPU.

loading terminal

The disadvantage of Infra Red is:

must have unobstructed line of sight

To minimize interference, communication cables are run as close to the _____ conductor as possible.

neutral

The PLC recognizes only _____.

open or closed contacts

The _____ is the speed at which light can travel through a material

optical property

NEC® 705.10 requires that a(n) _____ that indicates all interconnected power sources for the premises be installed at the service and the location(s) of the power production source(s).

permanent plaque or directory

The formula to calculate loses in decibels is describe by the logarithm of _________ ratio

powers

Harmonics are produced by loads that draw current in _______.

pulses

The ______ type connector has become very popular for connecting fiber optic cables because it offers excellent alignment and has less back reflection than other types of connectors.

push-pull

The reason that light can travel through an optical fiber is because of _______.

refraction

Control circuits are generally drawn as standard _____.

schematic or ladder diagrams

The hub of the structure wiring system is called

service center

A ______ -line diagram is an electrical schematic diagram for the utility interactive PV system.

single

Highlighting a contact means that there is a _____ through that contact.

complete circuit

The PLC is a special type of designed to perform a special function

computer

The PLC is a special type of designed to perform a special function.

computer

The first generation of Fiber Optic connectors were lacking the _________

straight alignment

If additional grounding electrodes are used, they are connected directly to ______ .

the array frame or structure

There are three basic types of fiber optic connectors: the ________ , the bayonet, and the push-pull.

threaded

The current rating of most outputs can range from 0.5 to about _____ amperes, depending on the make of the controller and the type of output being used.

three

It is necessary to use an ammeter that responds to ______ current when making a check for harmonics.

true RMS

Instead of Harmonic Analyzer we can use the following instruments for AVG and RMS:

two ammeters

The systems Zwave and Zigbee are both operating in

wireless communication

Transformers are typically designed for ______ -hertz operation.

60

are preferred over other types of photo detection devices because of their speed of operation.

Photodiodes

Modal Dispersion in Fiber Optic cable causes ___________ and distortion of the light signal.

attenuation

The two types of fiber optics splicing are

mechanical and fusion

A(n) ______ is connected across the AC input to help eliminate any voltage spikes that may occur.

metal-oxide varistor

The core of a fiber optic cable is composed of either _____ or plastic.

glass

A type of multimode cable called _____ cable has a core made of concentric rings.

graded

Harmonic currents in the neutral conductor induce _______ currents into the communication cable.

high-frequency

Fiber optic lighting systems are composed of three primary sections: the _____, the cable, and the end fixtures.

illuminator

In the example circuit shown in the text, pump 1 terminal of the selector switch is connected to input terminal _____.

3

Before a program can be developed from a ladder diagram, it is first necessary to determine the number of ______.

input and output devices

Which home automation system has dual channels for communication

insteon

The actual logic of the control circuit is performed by ______ .

internal relays

The equipment that converts the direct current produced by modules into an alternating current (ac) output is known as a(n) _____.

inverter

PLCs are designed to be programmed with ____.

ladder diagrams

The simplest way to convert a ladder diagram into a ______ is to make the changes in stages.

logic circuit

A single small inverter connected to each photovoltaic module is known as a _______ -inverter.

micro

The sequence and the frequency of the 11th harmonic are:

negative 660 hz

Electrical noise is such a problem in some installations that several manufacturers are using _______ instead of wires for connection to the I/O rack.

optical cables

The most popular way to isolate the CPU from the external circuit is through _____.

optical isolation

The ____ is used to connect the CPU to the load.

output module

The water pump circuit will cause the pumps to alternate running each time the _______ switch closes its contacts.

pressure

Inverter size is based on the _____ of the array.

capacity

When power is applied to an input, it will cause the contact assigned to that input to ______ .

change state

Fiber optic cables are composed of three sections: the core, the _______, and the sheath

cladding

In a logic diagram, each line of logic must end with a _____.

coil

The process of testing the PV system at the end of installation is called:

commissioning

A(n) _____ occurs when it is possible for one contact to open before another closes or for one contact to close before another opens.

contact race

A ground-mounted photovoltaic module array for a commercial building may be constructed so that it can be used as ______.

covered vehicle parking

The most common material used today for production of photovoltaic cells is _____ .

crystalline silicon

To determine harmonic problem in a single phase system you should first make ______ check

equipment

The minimum bending radius for coaxial cable is ____ times the diameter of the cable.

10

What is the value of THDF for RMS=200A and PEAK=340A?

0.83

A ratio of ____ between measurements made with a true RMS ammeter and an average value ammeter indicates no harmonic distortion.

1

The cable category that was used for phones only is

CAT 1

The ______ is the "brains" of the PLC.

CPU

Mega and Giga are corresponding to

Million and Billion

Which of the followings is NOT an organization for standards and installation requirements

NEC

is a measure of the range of colors that are emitted by the light source.

Spectral width

Harmonics are voltages or currents that operate at a frequency that is ______ the fundamental power frequency.

a multiple of

An inverter or ac module is required to automatically _______ its output when utility power is lost.

de-energize

With fiber optic systems, losses due to poor connection can be substantial. Losses are measured in _______.

decibels

An electronic device that is often used to help overcome the problem of induced noise is the _____.

differential amplifier

Photovoltaic modules in an array produce _____ electricity when exposed to sunlight.

direct current

Milli is the Prefix of a unit that ___________ by (to) thousand

divide

A ______ is used to smooth the pulsations caused by a bridge rectifier.

filter capacitor

A PLC assumes inputs to be ____ when a program is loaded into memory

low

The ZigBee wireless communications system uses which signal?

low-power radio

In the relay method of isolation, the CPU is isolated through the use of a(n) _______.

magnetic field

A dedicated PV system circuit breaker, suitable for backfeed and positioned at the opposite end of the bus from the _____ , is a requirement of NEC 705.12(B).

main circuit breaker

The maximum dc source current is defined by NEC® 690.8(A) as the sum of parallel module rated short circuit currents multiplied by _____ percent.

156

A ratio of ____ between measurements made with a true RMS ammeter and an average value ammeter indicates no harmonic distortion

1.0

Ammeters that respond to the average value convert the alternating current into direct current. This value must be increased by a factor of _____ to change the average reading into the rms value for a sine wave current.

1.111

The instantaneous peak value of current is equal to the rms value multiplied by ______.

1.414

In glass optical fibers, the index of refraction is approximately 1.46 to _____.

1.51

Coaxial cable can carry about _____ mbps of data.

10

Given that the internal clock that controls the operation of timers operates in 0.1-second intervals, what value do you have to program in order to get a one-second delay from the timer?

10

Open circuit voltage correction can be found in table ________ .

690.7

Referring to the information in Table 17-1, what is the maximum number of internal relays for this particular PLC?

75

The operation frequency of the zwave is:

868.42 M Hz

Cables that have passed the ______ testing will bear a "listing" marking.

UL

Exposed single-conductor cable is permitted to be installed for array interconnection, and only types ______ and listed PV wire are permitted.

USE-2

The electrical energy produced by a photovoltaic system can be stored using ______ to supply the building's electrical needs at night or on overcast days.

batteries

fiber optics wiring is less expensive than copper wiring because of the fact(s): a. last longer b. faster c. answers A and B d. immune to EMI

c. answers A and B

Fiber optics wiring is less expensive than copper wiring because of the fact(s) a. last longer b. faster c. both A and B d. immune to EMI

c. both A and B

The advantage of X10 system is: a. No wiring requires b. Affordable c. Easy to install d. All of the above

d. All of the above

Home Automation is also known as: a. wiring for the future b. Smart house c. Internet of things d. all of the above

d. all of the above

Home automation provides the ability to control _____ in a home. a. lighting (on, off, and dimming) b. heating and cooling c. audio/video entertainment d. all of the above

d. all of the above

The Fiber Optic lighting system is common in a. under water lighting b. art galleries c. building entrance d. all of the above

d. all of the above

When installing Audio/Video/Data cables it's important to: a. keep the runs short b. not to have sharp bends c. not to pull so hard d. all of the above

d. all of the above

Cable rated at Category 1 is ______ .

four-pair nontwisted cable and referred to as quad wire

WaveLength becomes shorter when the _________ increases

frequency

In the circuit designed to operate two well pumps, what is the protection mechanism?

fuse

Grounded conductors, whether dc or ac, must be identified with white or _____ insulation in accordance with NEC 200.6.

gray

Using the ______ and module frame grounding location specified in the module installation instructions is the only way to ensure connection integrity for the life of the system.

grounding hardware

The most accurate method for determining whether there is a harmonics problem is to use a(n) ______ .

harmonic analyzer

The speed of light in a vacuum is ________ than in a glass

higher

The selector switch can be set to any of _____ operating modes

three

The selector switch can be set to any of _____ operating modes.

three

In order to get maximum light on the array during of the day light hours, _________

tilting motors are installed underneath

Fiber optic cable is ____ electromagnetic interference.

totally immune to

THDF stands for ______.

transformer harmonic derating factor

Harmonics called _____ have a zero sequence.

triplens

The general procedure for inverter startup is to check _____ and current levels from the source (modules) to inverter closing disconnects and compare with expected values.

voltage