Electrical & Mechanical Part 1

91問 • 1年前

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is a form of energy generated by friction, induction or chemical change having magnetic chemical, and radiant effect. It is the motion of free electrons through a solid conductor. An electric current travels at the speed of light and therefore at the rate of conduction of an electric current is considered as instantaneous

Electricity

an english physicist is considered as the father of electricity for his studies on electric attraction and the electric force

William Gilbert

what are the basic particles of matter that contribute to electricity

electrons and protons

what are the two general classes of electricity

dynamic electricity (electrodynamic) and static electricity (electrostatic)

a combination of two or more electric cells capable of strong and supplying direct from electrochemical means

Battery

delivers electricity as soon as its parts as assembled, put together, provided that it is connected to a circuit

primary batteries

electricity from external source must be passed through it before it can deliver an electric current (changing the battery. uses art to supply emergency lightings repeats for hallways, stairways, exit to energize police and alarm system and certain types of signal system)

secondary/ storage batteries

a machine that converts mechanical energy to electrical energy

generator

the book of electrical energy utilize a day is in the form of alternating current, including energy for power and lighting

Alternators

this furnish electrical energy for elevators,escalators, intercommunicating telephone systems, control of signal systems, and clock systems

direct current generators

a machine that converts electrical energy to mechanical energy

motors

for converting one voltage to another, from lower to higher (set-up transformer) from higher to lower (step-down transformer).

transformers

what are the two major types of transformers

oil-insulated transformer & dry-type transformer

for changing altering current to direct current and vice versa

rotary converters

what is the maximum capacity of a H-frame transformer bank

1,000 kva

which are cluster-mountain transformer typically located

on a single pole

what type of liquid is used as insulation in Askarel-insulated transformer

A synthetic non-flammable liquid

a type of current which flows a constant time rate and in the same direction

direct current

a current which is periodically varying in time rate and in direction. it rises from zero to maximum, to aero, reverses its direction and again returns to zero.

alternating current

is a name after H.R Hertz

hertz

unit of electricity comprises approximately 6.25 x 10 18 electrons

coulomb

current represent as rate of flow of one coulomb or 6.25 x 10 18 electrons/ second through a given cross section

ampere

is the current carrying capacity of a water or cable expressing amperes, without undue heating

ampacity

is the electromotive force or potential difference between two points in the 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 war and then dripped into a liquid that conduct of carry electrons

Alessandro Volta

the resistance which will allow one ampere of current to flow when one volt is impressed upon it

ohm

what is the unit of electric power

watt or kilowatt

how many watts are equal to 1 kilowatt

1,000 watts

after whom is watt named

James Watt

according to ohm's law, a current in a DC circuit is directly proportional to what

voltage

in the formula I (amp) = V (volts) / R (ohms), what does 'R'

resistance

if the resistance in a circuit increases, what happens to the current, assuming the voltage remain constant

the current decreases

is the effective utilization of available energy by reducing peak loads and lowering demand charge. the control devices and system are referred to as a load shedding control, pick demand control, pick load regulation and power use control

electric load control

the installations electric clothes are analyzed and schedule to restrict demand by shifting large load to pick up r and control to avoid coincident operation

load scheduling and duty-cycle control

in conjunction with a duty cycle controller, the month is continuously mettered and an alarm set on when a bread determine the man level is exceeded

demand metering alarm

also called "rate control", it is an automated version of the demand meeting alarm system, where it automatically disconnects or reconnects loads as required

automatic instantaneous demand control

this controller operates 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

idealcurve control

are computerized system which continuously forecast the amount of energy remaining in the demand interval, then examine the status and priority of each of the connected loads and decide on the proper course of action

forecasting systems

to measure energy, the factor of time is introduce, such that; energy = power x time. A-C electric meters are basically small motors, whose speed is proportional to the power being used. The number of rotations is counted on the dials which are calibrated directly in kilowatt-hours

KWH meters

conducting elements are disconnected as to prevent the flow of electricity

Open circuit

a condition resulting from bridging any part of a circuit with conductor of a very low resistance

short circuit

is one in which the components are in tandem. All seperate loads of the circuit carry the same equal current and the total resistance, R is the sum of the resistance 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 carry wire of the circuit and also a neuture 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

supplies outlets for lighting and appliances including convenience receptacles

general purpose branch circuit

supplies outlets intended for feeding appliances. Fixed lighting is not supplied

appliance branch circuit

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

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 circuits do not require a protective raceway

low-voltage

how many watts per square meter a branch circuits shall be sufficient to supply a loaded in buildings excluding porches, garages and basements

30 watts per square

what is the maximum wattage recommended for a 20-ampere circuit, according to good practice guidelines

1,600 watts

How many 20-ampere applience branch circuts are minimally required to serve small appliances outlest in the kitchen, pantry, dining, and family room, accoting to the National Electrical Code

Why should convenience receptacles in an area be wired to at least two different circuits

to ensure that the entire area won't be without power if one circuit fails

what is the minimum wire gauge required for general- purpose branch cirents related to at 20 amperes

No. 12 AWG

On what amperage circuit loads and overcurrent devices should the circuit load for lighting and small appliances be limited

15 amp and 20 amp respectively

is a triple circuit, the lighting and outlet loads are connected between any phase leg and a neutral line while machineries and other bigger loals are connected to the phase leg only.

three phase electrical

general term including materials, fittings, appliances, fixtures, apparatuses used as part of, or in connection w/ an electrical installation

equipment

current consuming equipment/ fixed or portable ex: heating, cooking & small motor operated equipment

appliance

an accessory ex: locknut, bushing, or other part of a wiring system w/c is intended to perform a mechanical rather electrical function

fitting(s)

the point of delivery of electricity to a building by a public utility company. The service entrance consists of the following

service entrance

these are the conductors which extend from the street distribution main or distribution transformer to the service equipment of the building

service conductors

this affords the means of connecting or disconnecting the entire electrical service and of automatic protect against severe overloads and short circuits

service entrance switch

the device used by the utility company to determine power consumption

kilowatt hour meter

the decrease in voltage between two points on a power line, usually caused by resistance or leakage along the line

Line Drop

the supplying o utilitities required or demanded by the public

service

an auxilliary power station where electrical current is converted on where voltage is stepped up or down

substation

The portion of a service conductor extending from a service drop or service lateral to the service equipment of a building

service entrance conductor

A meter for measuring and recording the quantity of electric power consumed with respect to time

watt-hour meter

a fire-rated room housing a transformer and auxilliary equipment for a large building

transformer vault

contains the services equipment for a large building

switchgear room

equipment necessary for controlling, metering and protecting the electric power supply to a building

service equipment

one or a group of panels on which are mounted switches, overcurrent devices, metering instruments and buses

swithboard

for providing emergency power outage

standby generator

an emergency system designed to provide power automatically and instantaneously

uninterruptible power supply

A freestanding enclosure housing a disconnect switch, a step-down transformer and switchgear

unit substation

arey of the conductors extending from the service equipment to various distribution points in a building

feeder

the overhead portion of service conductors extending from the nearset utility pole to a building

service drop

the conductor and equipment for delivering energy from the electricity supply system to the wiring system of the premises served

service entrance

Any of several conducting rode installed at the top of a stucture and ground to divert lightning away from the structure. Also called air teminal

Lightning Rod

a device for protecting electric equipment from damage by lighting or other high-voltage currents, using spark gaps to carry the current to the ground without passing through the device

lightning arrester

a space between two terminals or electrodes across which a discharge of electricity may pass at a prescribed voltage

spark gap

is used by medium-sized and large buildings to step down from a high supply voltage to the service voltage.

transformer

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 busbars for controlling, distributing and protecting a number of electric circuits

main switchboard

includes a main disconnect switch and secondary switches, fuser and circuit breakers for controlling and protecting the electric power supply to a building. It is located in a switchgear room near the entrance of the service conductors

service equipment

The underground portion of service conductors extending from a main power line or transformer to a building

service lateral

the portion of a service conductor extending from a service drop or service lateral to the service equipment of a building

service entrance conductor

measures and records the quantity of electric power consumed with respect to time. Supplied by the public utility, it is always placed switch so that it cannot be disconnected for multiple-occupancy buildings, banks of meters are installed so that each unit can be metered independently

watt-hour meter

ls firmly embedded in the earth to establish a ground connection

grounding rod electrode

a service drop is connected from the nearest utility pole to the building service entrance point and enter the building through the weather head or entrance cap down to the electric power meter

overhead service

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.

underground service

Building laws Part 1

Mari Alberca · 100問 · 1年前

Building laws Part 1