Chapter 2 Flashcards
1
Q
Electricity is usually produced at a …..
A
Power station
2
Q
At the power station, electricity is usually generated in the range of ….
A
2.4 to 13.2 kV
3
Q
An industrial facility that house equipment to generate electricity from primary energy
A
Power Station
4
Q
Convert mechanical energy into electrical energy
A
Generators
5
Q
Efficacy rate of converting heat energy to mechanical energy
A
40% fossil-fuel plant, 30% nuclear plant
6
Q
Rotated by the generators, a shaft with conductor windings wrapped around an iron core, through stationary magnetic field, to produce current flow
A
Armature
7
Q
A rotary engine, is connected to the generator and drives the rotation of the armature shaft.
A
Turbine
8
Q
High - pressure steam moves through turbine this rotating the discs attached to turbine shaft.
A
Steam Turbine
9
Q
The most economical power stations typically generate power …..
A
continuously
10
Q
For economical transmission, a step up transformer steps up the voltage to above 39 kV, usually between 115 kV to 756 kV
A
Yes
11
Q
Power transmission at high voltages requires less amperage, there are lower power losses in the transmission lines.
A
True
12
Q
Small facilities in fenced yards that contain transformers, switches and other electrical equipment.
A
Power substations
13
Q
Generally generated transmit, and distribute three-phase AC power.
A
Power utilities
14
Q
It is very economical to carry power at high voltage because it requires smaller conductors.
A
Yuh
15
Q
A passageway where wires are connected to the load side of the meter enters the house or building.
A
Service entrance
16
Q
Service entrance comprises three cables…
A
Two hot and one neutral
17
Q
Extend from a pole-mounted distribution transformer to the building ‘s service entrance.
A
Overhead Service Entrance Conductors (Service Drop)
18
Q
Are direct burial cables and usually has three conductors: two hot wires and a neutral.
A
Underground Service Entrance Conductors (Service Lateral)
19
Q
It receives the service entrance conductors. It includes measuring power through an electric meter, a method of cutting off power, and over current protection devices that protect the service entrance conductors.
A
Service Entrance Equipment
20
Q
Instrument used by the utility company to measure and record electrical energy consumed.
A
Electric meter
21
Q
Used in building services rated up to about 400 A. This meter is a small electric motor with a speed that is proportional to the power consumed.
A
Feed - Through Meter
22
Q
Used in building services rated above about 400 A. Measure amperage through each ungrounded (hot) conductor.
A
Current - Transformer
23
Q
A required part of the service entrance equipment allows electrical service from the utility company to be switched off so that power is disconnected to the building installation. It is a set t of fuses or a circuit breaker that protects the service entrance conductors.
A
Service Disconnect
24
Q
A large cabinet or assembly of metal cabinets with electrical switched and devices connects/disconnected electric circuits, either manual or automatic.
A
Switch Board
25
Wall-mounted, single unit of one or more metal cabinets, including buses, automatic over current protection devices (fuses or circuit breakers).
Panelboard
26
Works as a regulator to change the voltage, current and phase of electrical power transmitted and distributed from the primary power source to a specific substation.
Transformers
27
Has a secondary voltage that is less than it's primary voltage. Typically used in buildings to reduce building system voltages to useable levels.
Step - Down Transformer
28
One with a secondary voltage that is greater than its primary voltage.
Step - up transformer
29
It is caused by internal losses from loading, high ambient air temperature, and solar radiation in exterior locations.
Transformers Heat Hazard
30
Has a single primary winding and single secondary winding.
Single Phase Transformer
31
Has three primary and three secondary windings.
Three Phase Transformers
32
Windings are connected in series, forming a triangle, thus resembling the Greek letter Delta. Only a single voltage level is available: the phase to phase voltage
Delta Connected Transformer
33
Has three independent transformer windings connected at a common point, called a neutral or star point.
Wye Connected Transformer (Y)
34
An electrical device that converts three-phase electric power without a neutral wire into three-phase power with a neutral wire.
Delta - Wye Transformer
35
Voltages that have the 1.732 as a multiplier are wye connections
Yuh
36
Safeguards the circuit component from overheating when the current flowing through the circuit reached an amperage that will cause an excessive or dangerous temperature rise in conductors
Overcurrent Protection (OCP) Device
37
Serve as automatic overcurrent Protection devices that are designed to open a circuit of the amount of current, in amps, that flows through the circuit exceeds the OCP Device rating
Fuses and circuit breakers
38
An OCP that acts as a switch that can be opened and close manually, and it automatically "trips off", which opens the circuit when the current flowing through it exceeds the circuit rating.
Circuit Breaker
39
The maximum voltage the circuit breaker can carry
Voltage rating
40
The voltage of the electrical circuit or system being protected by the circuit breaker must not exceed the circuit breaker voltage rating.
Truth
41
Most popular type of circuit breaker. It consists of the bimetallic strip that bends when heated by power loss.
Thermal - Magnetic Type
42
Protecting a single ungrounded conductor
Single Pose (SP)
43
When protecting two ungrounded conductors such as on a 240 V circuit
Two Pole (2P)
44
Used when protecting three ungrounded conductors on a three phase circuit
Three Pole (3P)
45
An overcurrent protective device with a circuit opening fusible part that is heated and severed by the passage of overcurrent through it.
Fuses
46
The older type fuses have a brass screw thread on the side and a central contact point. The more contemporary style, Edison - based, has a plastic line with a spring-type contact and a centre contact.
Plug Fuses
47
A cylindrical in shape and have the contact points at either end. These fuses are used in fuses panels and disconnect for amperages over 30 amps. It is used to protect electrical appliances such as motors, air - condition, refriherators
Cartridge Fuse
48
A special kind of fuse that allows electrical surge for a short time before it blows. They are desirable on circuits serving electric motors such as air conditioners and machinery.
Time Delay Fuse
49
An OCP device's overcurrent rating is the highest amperage it can carry continuously without exceeding a specific temperature limit.
Hmm
50
The highest current at rated voltage that a device is intended to k interrupt under standard test conditions
Interrupting Rating
51
It is a broad category of electrical or electronic machine or instrument designed to perform a specific mechanical, chemical, heating , or lighting function through the use of electrical energy.
Utilization Equipment
52
End - use pieces of utilization equipment designed to perform a specific function such as cooing, cleaning, cooling or heating.
Appliance
53
Permanently attached installations such as a built in electric cook top of oven
Fixed Appliances
54
Situated and used at a specific location but can be moved to another outlet such as refrigerator, clothes washer, or clothes dryer
Stationary Appliances
55
Appliances that can be easily carried or moved such as a hair dryer or toaster.
Portable Appliances
56
A component in an electrical system that is designed to carry but not use electricity
Electrical Device
57
The location in a branch circuit where electricity is used.
Outlet
58
A male connecting device that has two or more prongs that are inserted into a receptacle to connect to an electrical circuit.
Plug
59
NEMA stands for....
National Electrical Manufacturing Association
60
What colored screws are for connection to the ungrounded conductor
Brass-colored Screws
61
This screws are for the grounded or neutral conductor
Silver-colored screws
62
This screws are for the equipment grounding conductor
Green-colored screws
63
A device placed between two or more electrical conductors in a circuit to safely and intentionally open or close the circuit of to redirect the path of current in a circuit.
Simple Switch
64
Used in building electrical systems. They are designed to reduce the possibility of contact with bare electrical conductors and have current interrupting capability.
Safety switches
65
Designed for heavy industry, commerical, and institutional applications where safety, performance, and continuity of service are required.
Heavy Duty Safety Switches
66
Intended for industrial, general commercial and residential loads where economy is important and requirements are less stringent.
General Duty Safety Switches
67
Refers to the number of conductors the switch is opening and closing.
Pole
68
Refers to the number of operations a switch can perform
Throw
69
A simple on/off switch. It opens or closes a single ungrounded conductor in a circuit.
Single-Pole, Single-Throw Switch
70
Diverts current from one conductor path to another
Single - Pole, Double - Throw Switch
71
Opens or closes two conductors in a circuit
Double - Pole, Single - Throw Switch
72
Switches provide control from one or more points in a circuit.
Switching Configurations
73
Used to provide control from one point by opening or closing the ungrounded conductor in the circuit.
Single - Pole, Single Throw Switch
74
Used when multiple control points are needed.
Three - Way (S3) & Four Way (S4)
75
Can be used to adjust brightness of a lighting installation by adjusting the current flowing through the circuit.
Dimmer switches
76
Require a key to operate the switch
Kay operated switches
77
Deactivated a circuit after a preset time period has lapsed
Automatic Switches
78
Can be used to control the time period that a piece of equipment or a lighting installation operates
Time Clocks
79
Allow greater flexibility as they can easily be set for 7 day cycles
Electronic Timers
80
Sense light and open or close a circuit with the presence of light
Photocell Controls
81
Control a lighting or equipment installation by sensing occupants in a space.
Occupancy Sensors
82
Emit a high frequency sound that is in the range of 25 to 40 kilohertz and well above the capacity of normal human hearing.
Ultrasonic Sensors
83
Both infrared and ultrasonic Sensors work well in interior spaces such as classroom and offices.
Specialty Switches
84
Any materials that conducts electrical current
Conductors
85
Consist of smaller wire strand.
Stranded Conductors
86
Constructed of one single piece of metal. It is tougher than a stranded conductor but rigid and less flexible.
Solid Conductors
87
The best electrical conductor material. It has the least resistance of common materials.
Silver
88
This conductor material is used in building conductor (wiring) installations as a compromise between good conductivity and economy.
Copper
89
This conductor materials has significance weight and cost advantages than copper.
Aluminum
90
Covered with insulation that provides electrical isolation and some physical protection of the conductor material. It prevents loss of power and the danger of short circuits and ground faults.
Conductor Insulation
91
Contains more than one conductor bundled together in a factory assembly of wires.
Cable
92
It encases and protects the conductors, simplifying the installation of multiple wiring.
outer sheating
93
A wiring system composed of very thin cable with three or more conductors and special connectors and terminals. Designed to rest between the topside of a smooth continuous subfloor and carpet squares.
Flat Conductor Cable
94
Used in applications with voltages less than 30 V, such as wiring to doorbells, chimes, and thermostats.
Thermostat Cable
95
Made of stranded conductors within a flexible insulated sheathing material. They are designed for flexibility and bending.
Cord
96
A wiring method used knobs, tunes, and flexible nonmetallic tubing to protect and support single insulated conductors.
Concealed Knob and Tube Wiring
97
Heat generated by current flow through the conductor results in a loss of power
Power loss
98
Power loss formula
I²R = V²/R
99
Power loss is converted directly to heat. Power loss is equivalent to the heat produced.
100
The maximum current that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.
Conductor Ampacity
101
Current is measured in amperes or "amps". You must use the correct size wire for the current (load) requirement of the circuit to prevent nthe wire from overheating.
102
Thicker wires have larger cross sectional areas and can carry more electrical current without overheating. [True or False]
True
103
Voltage drop is directly proportional to power loss
104
Are electrical boxes and cabinets that are made of metal or non metallic materials that protect conductors, connections, controls, and other equipment.
Enclosures
105
Are metal and non - metallic enclosures that hold devices such as switched or outlets and safety permit wiring connections.
Electrical Boxes
106
Special type of electrical box used to enclose conductor connections.
Junction Boxes ( J-Boxes)
107
Kind of junction box that allows access to a raceway for snaking conductors through the raceway.
Pullbox
108
In most boxes and enclosures, it can be easily removed to allow wiring to enter the box.
Knockout
109
Required for various single or combinations of switches, convenience outlets, blank covers, and dimmers; plastic is a common used material attached with screws to the switch or receptacles.
Cover Plates
110
An enclosed channel such as conduit, tube, or gutter used for holding wires, cables, or bus bars.
Raceway
111
A heavy galvanized steel or aluminum tube that looks like the galvanized steel pipe used for plumbing applications, except it is much smoother and is labeled with a UL Listed stamp or label.
Rigid Metal Conduit
112
A galvanized steel or aluminum tube that has a thinner wall than rigid met conduit.
Intermediate Metal Conduit
113
Thin-walled galvanized steel or aluminum tube in nominal diameters up to 4 in. It cannot be threaded.
Electrical metallic tubing
114
A flame-retardant corrugated plastic tube that is semi flexible such that it can be bent by hand.
Electrical Nonmetallic Tubing
115
A thin-walled pipe of PVC joined with fittings that are solvent welded.
Rigid Nonmetallic Conduit
116
Similar to armored cable yet, installed without cables or wiring in it; wiring must be pulled.
Flexible Metal Conduit
117
Similar to flexible metal conduit but covered with plastic, a watertight jacket that is sunlight resistant.
Liquid Tight Flexible Metal Conduit
118
A flexible plastic conduit used similarly to flexible metal conduit
Liquid Tight Flexible Nonmetallic Conduit
119
Are hollow voids in floors made of precast concrete slabs (core slabs) found in certain precast concrete buildings.
Cellular Concrete Floor Raceways
120
Is of a standardized, factory - assembled enclosure consisting of outer duct - like housing, bus bars, and insulators.
Busway
121
A type of busway system that used to deliver a large amount of power with low voltage drop.
Feeder Busway
122
Another type of busway system used to provide power tap-offs at multiple points.
Plug - in Busway
123
Are sheet metal or nonmetallic, flame - resistant plastic through that serve as housing that encloses and protects conductors.
Wire gutters or wireways
124
Drive exhaust/ventilation fans, air-handling unit blowers, refrigeration equipment, air and fluid compressors and pumps, heating system circulators, and manufacturing equipment and machinery.
Electric Motors
125
Electric motors are rated in .....
horsepower (hp)
126
It is a fractional horsepower motor designed to operate on both AC and DC power. It operates at high speeds under light load and low speeds with a heavy load.
Universal Motor
127
The motor windings are configured so that single - phase AC power is split into two phases that are 1/2 put of phase. This type of motor starts slowly with low torque, so it cannot begin to heavy loads.
Split - Phase Motor
128
These motors use electromagnetic induction to cause the motor rotor to turn.
Induction Motors
129
It has a capacitor that stores and discharges energy to help start the motor rotor.
Capacitor - start Motor
130
Have one or more capacitors to help start and run the motor. It is more efficient and has a better starting torque than the split - phase motor.
Capacitor - run motors
131
Large motors operate more efficiently on three - phase motor rated at 71/2 hp draws a large amount of instantaneous current at startup.
Three Phase Motors
132
Motors above 1/4 hp are designed to operate on one of two different line voltages such as 115 V or 230 V. Larger motors operate more efficiently on a higher line voltage because of lower I2R losses. So, if a higher line voltage is available, it is used.
Dual - Voltage Motors
133
A switching device designed to start, stop and protect the motor. Provide functions such as reversing jogging plugging, operating at several speeds, or reduced current and motor torque levels.
Motor Controllers
134
A centrally located, sheet metal, a cabinet - like enclosure that houses starters and controls that control and protect several motors.
Motor Control Centers
135
The ______ panel of an MCC contains operator controls and gauges. The _______ of the MCC contains plug - in units such as starters, controls, and specialized units.
front, interior
136
A solid - state electronic power conversion device used for controlling the rotational speed of an AC electric motor.
Variable - Frequency Drive
137
_____________ occurs when a small amount of electrical current flows through the heart for 1-3 seconds.
Electrocution
138
Resemble regular receptacles, but they're so much more. Provide a permanent solution to childhood shock caused by the tampering with electrical outlets.
Tamper - Resistant Receptacles
139
Unintentional flow of electrical current between a power source, such as ungrounded (hot) wire, and a grounded surface.
Ground Fault Interruption
140
An electrical device that detects an extremely low leak ( 6 mA) of electrical current.
Ground Fault Circuit Interrupter (GFCI)
141
Generally used in place of standard duplex convenience outlets that are commonly found throughout the house.
Receptacle Outlet Type
142
Can be installed in the panelboard I'm buildings equipped with circuit breakers. Gives protection to the entire branch circuit.
Circuit Breaker Type
143
Frequently used in construction and outdoor settings with electric tools, mowers, trimmers, and similar devices.
Portable Type
144
Unintentional electrical discharge characterized by the low and erratic current.
Arc Fault
145
Occur across the break of a single conductor.
Series Arcing Faults
146
Result from direct contact of two wires of opposite polarity.
Parallel Arcing Faults
147
Arcs between a single conductor and ground.
Ground Arcing Faults
148
Provides enhanced protection from fores resulting from arc faults.
Arc Fault Circuit Interrupter ( AFCI)
149
A branch/feeder AFCI breaker with protection provided to branch - circuit wiring in the form of a circuit breaker.
Circuit Breaker Type
150
An outlet AFCI for protecting connected cord sets and power supply cords in the form of an outlet receptacle.
Convenience Outlet Type
151
Portable AFCI for protecting connected cord sets and power - supply cords that can be moved from outlet to outlet.
Portable Type
152
AFCI for protecting the power-supply cord connected to it.
Cord - Mounted Type
153
The tendency of GFCIs and AFCIs to trip frequently because both of them are extremely sensitive.
Nuisance Tripping
154
Silent, invisible magnetic fields produced any time electricity runs through a wire, an appliance, or piece of equipment
Extremely Low - Frequency Electromagnetic Fields
155
It is produced by high levels of EMF. Visible screen jitter in video displays.
Electromagnetic interference (EMI)
156
Instrument used in measuring EMF radiation levels from fans, electrical appliances, wiring, and power lines.
ELF ( extremely low - frequency ) meter
157
By using a conductive sheet material in front of the appliance or equipment
Passive shielding
158
Uses a system that sense the existence of a magnetic fields in the building area to be shielded.
Active shielding
159
Designed to detect and rapidly interrupt low - lev equipment ground faults.
Ground Fault Protection
160
A particular type of sending transformer. It encircles the conductors in the switchboard or panel board and produces a low - current output signal if all current flowing to the load does not return to the source through the phase or neutral conductors.
Current Transformer
161
A sudden increase in electrical current or voltage that is very short in duration.
Power Surge
162
A measure of the level of surge that an SPD can withstand.
Surge Rating
163
An electrical device that prevents power surges from reaching electric and electronic equipment or another device.
Surge Protection Devices (,SPD)
164
A semiconductor device used to mainly on AC power applications with surge ratings rangin from a few hundred to many thousands of amps
Metal Oxide Varistor
