MIDTERM EXAM (1) Flashcards
A form of energy generated by friction , induction, or chemical change, having magnetic, chemical, and radiant effect.
Electricity
It is the motion of free electrons through a solid conductor.
Electricity
An electric current travels at the speed of light and therefore the rate of conduction of an electric current is considered as ______________.
Instantaneous
An English Physicist and the father of electricity
William Gilbert
William Gilbert is an?
English Physicist and the father of electricity
William Gilbert studies on _________ and ____________
Electric Attraction
The Electric Force
Electricity is a property of the basic particles of matter, which like an atom, consist of the negative charge ________; the positive charge, ______; and the ________, which is not electrically charged.
Electron
Proton
Neutron
Sources of Electricity
Battery Generator
2 types of Battery
Primary Batteries
Secondary Batteries (Storage Batteries)
a combination of two or more electric cells capable of storing and supplying direct current by electro-chemical means
Battery
Delivers electricity as soon as its parts are assembled, or put together, provided that it is connected to a circuit
Primary Batteries
Electricity from some external source must be passed through it before it can deliver an electric current (charging the battery). Main uses are; to supply emergency lighting circuits for hallways, stairways, exits and to energize police and fire alarm systems and certain types of signal systems
Secondary Batteries (Storage Batteries)
A machine that converts mechanical energy into electrical energy
Generator
types of Generators
Alternating Current Generators (Alternators)
Direct Current Generators
Type of generator wherein the bulk of energy utilized today is in the form of alternating current, including energy for power and lighting.
Alternating Current Generators (Alternators)
These furnish electrical energy for elevators, escalators, intercommunicating telephone systems, control of signal systems, and clock systems.
Direct Current Generators
Enumerate the other dynamo electric machines
Motors
Transformers
Rotary Converters
Types of transformers
Outdoor Transformers
Indoor Transformers
Enumerate the Transformer rating
Step-up Transformers
Step down Transformer
Enumerate the outdoor transformers
H-frame transformer bank (capacity as high as 1,000 Kva)
Cluster mounted on a single pole (225 Kva capacity)
Pad Mounted
Enumerate the indoor transformers
Dry type
Askarel Insulated
Oil insulated
Synthetic non-flammable liquid
Askarel
installed in a fire rated transformer vault except when capacity not exceeding 112.5 Kva
Oil Insulated
For converting one voltage to another, from lower to higher (step-up transformer) from higher to lower (step down transformers.)
Transformers
2 major types of transformers
Dry type Transformers
Oil insulated Transformers
converting one voltage to another, from lower to higher
Step-up Transformer
For converting one voltage to another, from higher to lower
Step down Transformers
For changing alternating current to direct current and vice versa
Rotary Converters
Types of Current
Alternating Current
Direct Current
A current which flows at a constant time rate and in the same direction
Direct Current
Direct current flows at a ________ time rate and in the ______________direction.
constant | same direction
A current which is periodically varying in time rate and in direction
Alternating Current
Alternating Current is ______________________ in time rate and in direction
periodically varying
Alternating Current rises from zero to maximum, falls to aero, reverses its direction and again returns to zero. A complete set of these changes is called as________.
Cycle
The number of times the current goes through the above cycles per second is called the __________ of the alternating currents and is referred to as the _______.
Frequency | Hertz
The frequency commonly used for lighting is ______ cycles per second and motors ______ cycles per second
Lighting - 60 cycles per second
Motors - 25 cycles per second
What are the unit of Quantity
Coulomb
Ampere
Unit of Electric Potential
Volt
Unit of Resistance
Ohm
Unit of Electric Power
Watt | Kilowatt
Unit of energy
Watt hours | Kilowatt hours
A coulomb of electricity comprises approximately __________.
6.25x10.18 electrons
An ampere of current represents a rate of flow ________.
one coulomb or 6.25x10.18 electrons/seconds
Ampere is named after?
Andre M. Ampere
is the current carrying capacity of a wire or cable expressed in amperes, without undue heating.
Ampacity
s the electromotive force or potential difference between two points in an electric field which will move a charge of one coulomb between these points.
Volt
Volt is named after ___________________, an Italian Scientist who discovered that electrons flow when two different metals are connected by a wire and then dipped into a liquid that conduct or carry electrons.
Alessandro Volta
The resistance which will allow one ampere of current to flow when one volt is impressed upon it.
Ohm
In direct current circuit (d-c) this unit is called ___________and is abbreviated___________
Resistance (R)
In alternating current circuit (d-c) this unit is called ___________ and is abbreviated___________
Impedance (Z)
The watt is named after _______, a Scottish inventor
James Watt
Enumerate the Electric Load Control
Load Scheduling and Duty-Cycle Control
Demand Metering Alarm
Automatic Instantaneous Demand Control
Ideal Curve Control
Forecasting System
Formula of Ohm’s Law
1 amp = V (Volts) / R (ohms)
The installation’s electric loads are analyze and scheduled to restrict demand by shifting large loads to off-peak hours and controlled to avoid coincident operation.
Load Scheduling and Duty-Cycle Control
a type of Electric Load Control wherein conjunction with a duty cycle controller, demand level is exceeded.
Demand Metering Alarm
a type of Electric Load Control also called rate control
Automatic Instantaneous Demand Control
a type of Electric Load Control that operated by comparing the actual rate of energy usage to the ideal rate, and controls KW demand by controlling the total energy used within a metering interval.
Ideal Curve Control
a type of Electric Load Control that are computerized systems which continuously forecast the amount of energy remaining in the demand interval, the examine the status and priority of each of the connected loads and decide on the proper course of action
Forecasting System
According to OHM’s Law the higher the voltage the _______ current
Larger Current
Types of Circuit
Series Circuit
Parallel Circuit
According to OHM’s Law the higher the resistance the _______ current
Lower Current
Defined as a complete conducting path carrying current from a source of electricity to and through some electrical device or load and back to the source
Electrical Circuit
The most elementary of all wiring system
Two wire circuit
Type of wire circuit which is the return of wire carrying the circuit back to the source of supply.
Neutral or Grounded Wire Circuit
Type of circuit that is one in which the components are connected in tandem. All separate loads of the circuit carry the same equal current and the total resistance, R, is the sum of the resistances around the circuit.
Series Circuit
is one in which the components or loads are so arranged that the current divides between them. Each outlet has a live wire connected to the current carrying wire of the circuit and also a neutral wire or grounded wire connected to the return wire of the circuit. With this system, the total current flowing through the circuit is the sum of the current flowing through each outlet.
Parallel Circuit
What are the Classifications of Branch Circuits
General Purpose Branch Circuit
Appliance Branch Circuit
Individual Branch Circuit
A Classifications of Branch Circuits that supplies outlets intended for feeding appliances. Fixed lighting is not supplied.
Appliance Branch Circuit
A Classifications of Branch Circuits that supplies outlets for lighting and appliances, including convenience receptacles.
General Purpose Branch Circuit
A Classifications of Branch Circuits that is designed to supply a single specific item, such as a motor load or a unit air-conditioner
Individual Branch Circuit
The portion of an electrical system extending from the final overcurrent device protecting a circuit to the outlets served by the circuit.
Branch Circuit
A panel for distributing power to other panels or to motors and other heavy power-consuming loads. Controls, distributes, and protects a number of similar branch circuits in an electrical system.
Distribution Panel
Of or pertaining to a circuit in which alternating current below 50 volts is supplied by a step-down transformer from the normal line voltage used in residential systems to control doorbells, intercoms, heating and cooling systems, and remote lighting fixtures.
Low-Voltage Circuit
The point of delivery of electricity to a building by a public utility company.
Service Entrance
General term including materials, fittings, devices, appliances, fixtures, apparatuses used as part of, or in connection w/ an electrical installation.
Equipment
These are the conductors which extend from the street distribution main or distribution transformer to the service equipment of the building
Service Conductors
an accessory ex: locknut, bushing, or other part of a wiring system w/c is intended to perform a mechanical rather electrical function.
Fittings
current consuming equipment / fixed or portable ex: heating, cooking & small motor operated equipment
Appliance
The device used by the utility company to determine power consumption.
Kilowatt Hour Meter
This affords the means of connecting or disconnecting the entire electrical service and of automatic protection against severe overloads and short circuits.
Service Entrance Switch
The supplying of utilities is usually accomplished by the utility.
Service
The reduction in voltage between
two points in a power line.
Line Drop
Conductor from the point of connection to the service drop or service lateral to the service equipment of a building.
Service Entrance Conductor
A meter for measuring and recording the quantity of electricity that is consumed with respect to.
Watt-Hour Meter
A fireproof room containing a transformer and auxiliary equipment for a large building.
Transformer Vault
For providing emergency power during power outages.
Standby Generator
An emergency system designed to provide power automatically and without noticeable electrical transients.
Uninterruptible Power Supply
An assembly of power station units where electrical current is converted, switched, or changed (stepped-up or down)
Substation
The overhead portion of service conductors between the last relevant utility pole to a building.
Service Drop
The underground portion of service conductors between the utility power line or transformer to a building.
Service Lateral
Equipment necessary for
controlling, metering and
protecting the electric
power supply to a building
Service equipment
A large panel, switchboard, or assembly of switchboards which are mounted switches,
fuses, and busses, usually accessible from the rear as well as from the front.
Switchboard
All of the conductors between the service
equipment and the various distribution points in a building.
Feeder
A freestanding enclosure housing a disconnect
switch, fuses, a power transformer and auxiliary equipment.
Unit Substation
The conductor and equipment for delivering energy from the electricity supply system to the wiring system of the premises served.
Service Entrance
A grounded metal conducting rod installed on the top of a structure and grounded to divert lightning away from the structure. Also called lightning arrester.
Lightning Rod
A device for protecting electric equipment from damage by transient high-voltage currents; using spark gaps to carry the current around the protected device without passing thru the device.
Lightning Arrester
A space between two terminals or electrodes in which a discharge of electricity may pass at a prescribed voltage.
Spark Gap
is used to medium and
large buildings to step down from a
high supply voltage to the service
entrance voltage
transformer
is the main disconnect
for the entire electrical system of a
building, except for any emergency power
systems.
Service Switch
_________ extend from a
main power line or transformer to
the service equipment of a building.
Service Conductors
is a panel on which
are mounted switches, overcurrent devices,
metering instruments and busses for
controlling and protecting a number of
number of electric circuits.
Main Switch Board
Is a firmly embedded in the earth to establish a ground connection
Grounding Rod or Electrode
Components of the Building Electrical System
Service Entrance
Main Switch Board
Feeder Circuits
Sub-feeder Circuits
Branch Circuits
Panel and Sub Panel Boards
Types of Service Entrance
Overhead Service
Underground Service
A type of service entrance wherein a “service drop” is connected from the nearest utility pole to the building service entrance point and enter the building through the weather 1 head or entrance cap down to the 2 electric power meter.
Overhead Service
A type of service entrance that consists of a buried concrete enveloped raceway extending from the building to the property line where it is tapped to the main by a service lateral. The cable recommended is the USE type cables.
Underground Service
Serves as the control, protection and metering of the main feeders
Main Switchboard
is a set of conductors which extends from the main switchboard to a distributing center (panel board) with no taps or connections to other devices at the source and the distributing center.
Feeder Circuit
smaller panel boards are called?
Sub-panel boards
are line extensions of a feeder, fed through a panel board or cut-out, or from one distributing center to another and having no taps or connections to other devices at the two distributing centers
Sub-feeder Circuits
The overhead portion of service conductors extending from the nearest utility pole to a building.
Service Drop
Serves to distribute power from the main feeders to smaller panel boards
Sub-feeder
These are small capacity conductors which deliver energy to lamps, motors and other loads within the circuit
Branch Circuit
are free standing assemblies of switches, fuses and circuit breakers that provide switching and feeder protection to a number of circuits connected to the main service
Switchboard or Switchgear
These serve to control and protect the sub feeders and branch circuits
Panel Board and Sub-panel Boards ( Fuse or Cut-outs)
A switch suitable for use on the entire electrical system of a building except for any emergency power systems.
Service Switch
A board on which are mounted the fuses, switches and circuit breakers for controlling and protecting a number of branch circuits fed from bus bars. It is also called a cabinet and accessible from the front only.
Panel
Bus is also called as?
Busbar
A heavy conductor (usually in the form of a solid copper bar) used for carrying and distributing large electric currents.
Bus
A conductor used to connect the electrical system intentionally connected to a ground connection.
Ground Wire
A conductor or conductors and a grounding conductor that connects the equipment grounding conductor or the grounded conductor of a circuit to a grounding electrode.
Grounding Electrode
A single panel or group panel units designed for assembly in the form of a single panel.
Panel Board
A device containing a strip of wire that melts when excess current melts under the heat produced by the excess current thereby interrupting the circuit.
Fuse
A device that automatically interrupts an electric circuit to prevent excess current from damaging apparatus in the circuit. Unlike a fuse, it may be removed and reset without replacement of any components.
Circuit Breaker
These are the lighting, power, and motor loads and wiring devices which are directly handled and utilized by users
Utilization Equipment
