rmse lecture

8/12/2019 RMsE Lecture

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Ulysses B. PaguioBSEE 79/ BSECE 80 MIT1stEDITION


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1. Definition of Electrical Terms and Units 1.2 VOLTAGEis the electrical pressure that causes the

positively charged atoms to move through a conductor

material. This is also referred to as electromotive force.

1.3 VOLTunit of voltage named after Alessandro Volta.

1.4AMPEREunit of electric current named after Andre

Ampere.


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1.5 WATTunit of electrical power energy named after

James Watt.

1.6 RESISTANCEis the opposition to the flow ofcurrent.

1.7 OHMSunit of resistance named after Gerry Ohms.

1.8 CONDUCTANCEallows the flow of current.


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1.9 MHOunit of conductance.

2.0 CONDUCTORmaterial that allows the flow of

electric current.

2.1 INSULATORmaterial that resists the flow of

electric current.

2.2 CURRENTrate of flow of electric force in the

conductor.


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2.3 VAvolt-ampere, unit of apparent power.

2.4 PROTONSpositively charged atoms.

2.5 ELECTONSnegatively charged atoms.

2.6 DIRECT CURRENT flow of electricity in one direction.Sources are dry cell or storage battery.

2.7ALTERNATING CURRENT flow of electricity thatchanges in strength. Its strength according to active wavewhich is sinusoidal in nature =. It reverses its direction oneach alternation.


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2.12 CAPACITORalso named condenser-any device thatstores electric charges so as to possess electrical charges.

2.13 CAPACITANCEis a measure of how a capacitor stores

an electrical charge.

2.14 FARADunit of capacitance.

Q= CE

2.15 ELASTANCE reciprocal of capacitance.

2.16 DARAF unit of elastance, reciprocal farad.


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2.17 INDUCTANCEa measure of how much counter

electromotive force is generated in a circuit for a changein current through the circuit.

2.18 HENRYunit of inductance named after Joseph

Henry.


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2.5 - resistor

2.6 - capacitor

2.7 inductor or choke coil

2.8 - Direct CurrentDC


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2.9 - Alternating Current

2.10 - battery cell or storage cell

2.11 - generator

2.12 - relay

2.13 - normally open contact (NO)

AC

G

R


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2.13 - normally closed contact (NC)

2.14 - varmeter

2.15 - power factor meter

2.16 - frequency meter

2.17 - ground detector

PF

FM

VM

GD


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2.18 - main switch board

2.19 - auxilliary switch board

2.20 - energy switch board

2.21 - motor control center

2.22 - semiconductor diode

MCC

ESB

ASB

MSB


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2.23 - transistor

2.24 - photoelectric cell

2.25 - synchroscope

2.26 - switch

2.27 - 3 way switch

SYN


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2.28 - water light type switch

2.29 - flush type switch

2.30 - 2 pole receptacle

2.31 - 2 pole receptacle w/ grounding

contact

2.32 - flush type 2 pole receptacle


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2.33 - Nm waterlight type bell

2.34 - waterlight type bell

2.35 - engine control console

2.36 - boiler control panel

2.37 - data logger


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2.38 lighting arrester

2.39 surge arrester

2.40 ground (earth)

2.41 ground (frame)

2.42 service entrace


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2.43 - safety switch

2.44 circuit breaker

2.45 - fuse

2.46 main distribution panel

2.47 S single pole switch


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2.48 S2duplex switch 2.49 S2Pdouble pole switch

2.50 S3Pthree pole switch 2.51 S3Wthree way switch

2.52 S4Wfour way switch 2.53 S

4Wfour way switch

2.54 SAD - automatic door switch

2.55 SKkey operated switch 2.56 SMmaster selector switch


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2.57 SRM remote control switch

2.58 junction box switch

2.59 pull box switch

2.60 power panel board

2.61 lighting panel board


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2.62 - ceiling incandescent lamp

2.63 - wall incandescent lamp

2.64 - ceiling fan

2.65 - wall clock

2.66 - single convenience


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2.67 - duplex convenient outlet

2.68 - waterproof convenience outlet

2.69 - cooking range outlet

2.70 - telephone outlet

2.71 - intercom outlet


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2.72

2.73 - push button

2.74 - buzzer

2.75 - bell

2.76 - horn


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2.78 - amplifier

2.79 - annunciator

2.80 - loudspeaker

2.81 - heat detector

2.82 - conduit wiring


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2.83 - open wiring

2.84 - underground wiring

2.85 E E - emergency wiring

2.86 FA FA - fire alarm wiring

2.87 T T - telephone wiring


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2.89 IC IC - intercom wiring

2.90 CCTV CCTV - closed circuit TV wiring

2.91 - ac generator

2.92 -dc generator

2.93 - ac motor


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2.94 -dc motor

2.95 -- converter, transmitter


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Electric Circuits a closed path for electric current toflow.

Ohms Law states that the current flowing in an electriccircuit is directly proportional to impressed electromotive

force applied to the circuit and inversely proportional tothe resistance of the circuit.

E= IR

Where: E= impressed voltageI= drawn current in ampere

R = resistance in ohms


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Electric Power rate of using or consuming a substantialamount of electrical energy.

P= EI P=E2/R

P=I2RWhere: P=electrical power in watts

V =voltage in volts

I = current in ampere

R = resistance in ohmsother units of Electrical Power:1 horsepower (1HP) = 746 watts

1 kilowatt (1KW) = 1000 watts

1 megawatt (1MW) = 1,000,000 watts


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Kilowatt-Hour (KW-HR) a unit in w/c electricalenergy is sold to customer.

KW-HR = Pt

Where: P electrical energy in wattst time in hours

Ohms Law states that the current flowing in an electriccircuit is directly proportional to impressed electromotive

force applied to the circuit and inversely proportional tothe resistance of the circuit.

E= IR

Where: E= impressed voltage

I= drawn current in ampere


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R =L/A where: R= resistance in ohmsL= length in meter

A= conductor cross sectional area in mil, CM (circular mil)

= resistivitythe above equation states that the resistance of a specific

conductor is directly proportional to its length and

inversely proportional to its cross sectional area

depending on the element of its conductor whethercopper, zinc.


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Example Problem No. 1What amount of current in a circuit having a resistance of

10 ohms on a 100 volts circuit.

Solution: I=E/R ; I= 100V/10= 10 amperes

What is the voltage impressed across a resistance of 3

ohms if a 20A current is flowing to the electric circuitE= IR ; E= 20A x 3= 60 volts


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i. Generator a machine that convertsmechanical energy to electrical energy.

ii. Prime Mover a machine that drives thegeneratoriii. Parts of A DC Generator

a. Yoke another term is frame w/c iscylindrical in form in w/c an even no. ofpoles are bolted, either made in cast iron orcast steel.


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b. Armature Core and Winding the core iscylindrical in form made from sheet laminations w/ slots

that carry the armature windings.

c. Poles and Field Windings used to generate themagnetic lines of flux.

d. Commutator cylindrical in shape and consists ofhard drawn copper conductor insulated from each other

and is sometimes called as mechanical rectifier. e. Brushes used to connect the external load circuit

to the armature. It is made from carbon particles that

are held in position by spring pressures.


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iv. Exciteran external equipment used to supply voltage to the fieldwindings of a generator.

v.Separately-excited Generator field winding is excited from itsown generated in the armature.

vi. Empirical Formula of DC GeneratorE= PNZ/60a

Where:E= generated emf volts

P= no. of poles

N= speed of prime mover in rpmZ= no. of armature conductors

=flux per pole in webera= no. of armature current paths

1 weber = 1 x 108maxwells


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viii. Short Generator the field and armature

windings are connected across each other.

E= V + Ia

Ra

Ia

= ISH

+ I

ISH= V/RSH I=P/V


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x. Long Shunt Compound Generator the series

field winding is connected in series w/ the

armature winding while the short field winding is

connected across the series combination.

Ia= ISH+ I ISH= V/RSH I=P/V

E= V + Ia(Ra+ RSH)


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Ia = I + Ish I =Ise

E = V + IaRa + IseRse I=P/V

Ish =V + IseRse/Rsh

Where:

E = generated emf voltsV = terminal or load voltage in volt

Ra = armature winding resistance in ohms

Rsh = shunt field winding resistance in ohms

Rse = series field winding resistance in ohms

Ia = armature current in ampereIsh = shunt field current in ampere

I = load current in ampere

P = power drawn by the load in watts


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xii. Power Generated (Pg) in the armature of aDC Generator

P = EIgxiii. Voltage Regulation (VR) percentage usein voltage at the terminals of a generatorwhen the load is removed.

% VR= (VNLVFLX 100%)/ VFLWhere: VNL= no. load terminal voltage in volts

VFL= full load terminal voltage in volts


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xiv. Requirements of operating DC generatorsin parallel:

a. Same external load characteristics orbehaviors are loadedb. Terminal voltage of each machine must

be equal

c. Terminal polarity must be the same


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The basic parts of a DC generator are the same basic parts of a DCmotor.

Counter or back emf voltage included into the armature conductors of

a DC motor when the armature rotates.

Torque characteristics of a DC motor

The speed (N) of a DC motor is directly proportional to the back emf(Eb) and inversely proportional as the flux () generated per pole.

The Torque (T) exerted by the DC motor is directly proportional toboth the armature current drawn and the flux () generated per pole

T=K1Ia

Where K0& K1proportionality constant


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Horsepower rating of a DC motor- maximum safest mechanical power it candeliver to the load.

Where HP= mechanical power in horsepower

N= speed of the motor in Rpm

T=torque exerted by the motor (N-m/J)

K=proportionality constant= 44,760 if T is in newton-meter

= 33,000 if T is in pound-foot

Reversion of Rotation

The direction of rotation of a DC motor is reversed be any of the followingmethods

Interchange the terminals of the armature windings

Interchange the terminals of the field windings


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Speed ControlsThe speed of a DC motor can be controlled by varying

the resistance of a rheostat connected in series in any of the

following: A rheostat in series with the armature windings

A rheostat in series with the field windings (most commonmethod)

A rheostat in series with the supply terminals


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It is an alternating current generator. The working principle isthe same as that of a DC generator, however, in alternators itis the field which is made to rotate while the armature is kept

stationary. Basic parts of an alternator

Rotor (armature)- moving parts

Stator (field poles and winding)- Stationary parts

Relation between speed, poles and frequency of thegenerated emfwhere N=speed in rpm

P=no. of polesf=frequency in hertz


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Purpose of the open and short circuit tests: To evaluate the synchronous impedance and asynchronous

reactance of the alternator per phase.Where Zs-synchronous impedance per phase

Xs-reactance per phase

Requirements for parallel operation ofalternators;

Operating frequency must be equal.

Line to line voltage must be equal.

Phase sequence must be equal.


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Transformers- a static device used to transform electrical energy fromone voltage to another without a change in wave shape andfrequency:

Classifications according to care used:

Core type transformer Shell type transformer

According to method of cooling the windings:

Self cooled transformer

Oil self cooled transformer

Force oil cooled transformer

Source air cooled transformer


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According to purpose or applications

Distribution type transformer

Instrument type transformer like current and voltagetransformers

Power transformer

Welding transformer

Rectifier transformer

Regulating transformer

Lighting transformer

According to voltage transformation

Step-up transformer (low to high)

Step-down transformer (high to low)


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A. Electrical Tools

Classifications:

Hand tools- tools operated by hands without the need ofelectricity to operate it.

Examples: screwdrivers, electrical pliers, hacksaw, etc.

Machine tools- tools operated by our hands with

electricity to operate it.Examples: Soldering gun, electric pipe cutter etc.


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Basic type of electrical tools: C-clamp- used in holding objects together while they are being

assembled.

Center punch-used for marking metal parts

Electrician knife- used by electricians to remove insulation oflarge wires or being cables

File-used to remove rough edges

Gimlet-used to make an initial hole for wood screws

Hacksaw-used for cutting metals

Hammer-used for striking hard objects like nails etc.

Claw hammer- used for pulling nails

Ball pen hammer- used to flatten metal surfaces

Soft-laced hammer-used in rewinding jobs


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Hand drill and bitt used for boring holes

Hickey-used in bending small size pipes

Micrometer-used to measure the diameter of small wires in mills

Pipe cutter- used to cut small pipes

Pipe threader- used in threading pipes like RSC

Pipe vise- used to hold down the pipes while being cut

Pliers-used for cutting, twisting or gripping electrical components

Lineman pliers- side cutting pliers

Long nose pliers- used for twisting, cutting and gripping orholding wires

Diagonal pliers-simply called cutter

Mechanical pliers


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Wrenches- used to tighten or loosen objects

Adjustable wrench- size is adjustable

Open-end wrench- used to grip the nut only in twosides

Box wrench- used to grip the nut in all sides

Allen wrench- used for hexagonally shaped nuts

Vise-grip wrench- used to lock on objects and grip it

Pipe wrench- used for gripping pipes only


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Types of indicating instruments according toconstruction:

Permanent magnet moving coil meter- also known asdarsonval meter, a coil wound on soft iron core placedbetween the poles of a permanent magnet. The needleof the meter is attached to a core and will deflect inproportion to the current in the coil. This was invented

by Arsen d Arsonval and named in honor of Galvani


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ADVANTAGES:

*Very accurate

*Requires small operatingcurrent*Energy consumption islow*Scale is linear

DISADVANTAGES:

*Only used in DC

measurements*Cost is high

*Error due to aging ofsprings and magnets


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Moving Iron Meter- also called iron vane meter, twopieces of triangular pieces of soft iron called vanes are

placed inside a coil of wire. One iron vane is free to movewhile the other is fixed. Pointer of the meter isconnected to the moving vane. Once current flowsthrough the coil, moving vane will repel with the fixedbar and move causing the pointer to deflect inproportion to the current flowing through the coil.


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ADVANTAGES:

*Cheapest

*Used in both AC & DCmeasurements

*Can stand for

momentary loads

DISADVANTAGES:

*It consumes more

energy*Error is high

*Scale is non linear


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Dynamometer-basically consists of fixed coil

(current coil) & a moving coil (potential coil). This is

based on the principle that a mechanical force exists

between two current carrying conductors. Movingcoil is attached to the moving parts under the action

of deflecting torque, pointer moves over the scale.


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ADVANTAGES:

*Used both in AC & DC

measurements*Not affected by

external fields

DISADVANTAGES:

*Not uniform scale

*More expensive thanthe 2 meters

*Resistivity is low


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VII-ELECTRICAL CIRCUITS IN BUILDING

7.1 Service Entrance:-defined as that portion of the supply conductor which extends from the

street main duct or transformer to the service or switchboard of the building

supply. The National Electrical Code (NEC) defined it as the conductor and

equipment for delivering energy from the electrical supply system of the

premises served. It is categorized as overhead or underground service.

a) Overhead service entrance- is the common type of service wire installed by

electrical power supply companies (Like MERALCO and Electric Cooperatives)

for industrial, commercial and residential consumer users. A service drop is

connected from the nearest utility pole to the building service entrance point and

enter the building through the weather head down to the electric power meter.


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b) Underground service entrance- consists of a conduit raceway extending from

the property line where it is tapped to the main. The cable recommended for

such purpose is the USE type (Underground Service Entrance) cable. Most

buildings service entrances are connected to the secondary line voltage below

600 volts. Service entrance can be 2, 3 or 4 wires including a grounded neutral

wire. Service entrance may be 2 wires of 120/240 volts or 4 wires with 120/208

or 277/400 volts for larger installations. Size of wires series from 60, 100 or 200

Amperes depending on the demand load but generally 2 wires service entrance

does not exceed 60 Amperes.

c) Electric meter- is generally installed outside the building at the property line

wall or electric posts ready access to the utility meter reader, making it difficult to

tamper or to install jumpers.


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d) Feeder- as per National Electric Code (NEC) it is defined as all circuit

conductors between the service equipment or the generator switchboard of an

insulated plant and the final branch circuit over current device.

e) Main- is a feeder interior wiring extending from the service switch, generator

bus or inverter bus to the main distribution center or electric servcie equipments.


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f) Phase conductor wires are color coded:

a) neutral- white or grey color

b) First Hot Line A- black color

c) Second Hot Line B0 red color

-neutral conductor wire carries no current when the load on line A and line B are

equal, since neutral line is grounded, it is neutral zero potential being ahlf way in

voltage between line A & B.

g) Various electrical diagram representations;

I. Block diagram- type of representation wherein major equipments are

represented by rectangles or blocks.

II. Riser diagram- type of representation showing the spatial relations

between components.III. One line or single line diagram- used electrical symbols instead of

blocks.


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h) System voltageis the power supply by a utility company like MERALCO and

Electric Cooperative or what the transformer produces.

i) Utilization voltageis the current being utilized after some normal voltage drop.

Electric motors are rated at utilization voltage. Transformer is rated at 240/480

volt while an electric motor is 230/460 volts. To indicate that a motor is rated at

480 volts is not correct. Motors for 208 and 240 volt system are rated at 200 and

230 volts and so on. They cannot be changed interchangeably without seriouseffect on the motor performance. Thus, when specifying transformer, use the

system voltage for electric motors use utilization voltage, a 4% utilization voltage

drop is within the internal motor tolerance.


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j) Grounding and Ground fault

i. Ground- NEC defines it as zero voltage. The purpose of grounding the

circuit should not be broken or fused to maintain a solid and uninterrupted

connection to the ground. An established ground automatically becomes the

reference for all voltage in the system.

ii. Grounding could be accomplished by;

1. Connecting to a buried cold water main.

2. Connecting to a ground rod.

3. Connecting to a buried ground plate.iii. Code requires that all new installations shall use grounded outlets

such as GFI &GFCI devices on all appliances circuits particularly on

outdoor and bathroom locations of outlets.


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k) Reasons for Grounding the Circuit System:

1. To prevent a sustained contact between the low voltage secondary

line and the high voltage primary line in case of insulation fire.

2. To prevent single grounds from being noticed or detected while

second ground occurs that could totally disable the secondary line.

3. To facilitate in locating the ground faults.

4. To protect against a short sudden rush of electric current in the

circuit.

5. To establish a neutral at zero potential not to be interrupted byswitches or protective devices.

6. To connect the service entrance to ground only at one point and to

use colored wires for easy identification.


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l) Circuit Safe Load

i. Brach Circuit- is the technical term for house wiring installation that

varies in sizes depending upon the load it is to serve. Load refers to the

electricity drawn or consumed by lighting fixtures, appliances, equipments etc.

ii. The code provides that wirings for electrical circuitry shall be of the

types RHW , T, THW, TW, THWN, XNHW in a raceway or cables.

iii. That on a 20 Ampere circuit, a single appliance shall not draw a

current in excess of 16 Amperes.

v. That if, a branch circuit, a single appliance draw shall not exceed 24amperes.

vi. That on a 20 Amperes circuit, a single appliance draw shall not

exceed 24 amperes.

vii. That a heavy lamp holders shall be rated not less than750 watts.

viii. That a 30, 40 Amperes circuit shall not be used for fixed lighting

residence.

ix. When loads are connected for a long period of time, actual load shall


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g p ,

be computed not too exceed 80% of the fuse rating, long period of time refers to

electric motors, air conditioner and other similar units with a continuous rating.

x. That a continuous type load shall be considered 125% of the actual

load in all load calculations.

xi. A single receptacle on individual branch circuit shall have a rating of

not less than a circuit.

xii. Receptacles leading portable and or steady appliance shall be

limited to loads of 80% of their rating that is;

a) 12A for 15A receptacle

b) 16A for 20A receptaclec) 24A for 30A receptacle

xiii. The no. of outlets in a circuit shall be limited to:

6 outlets on a 15A circuit

8 outlets on a 20A circuit

xiv. All receptacle outlets of 20 Amperes or less rating in one family and

multifamily dwelling and in guest rooms of hotels and motels except thoseconnected to the receptacle circuits specified in Section 3.3.13 of the code shall

be considered as outlets for general illumination and no additional load

calculations shall be required for such outlets.


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VIII-ILLUMINATION AND ELECTRICAL BILLING

OF MATERIALS

8-1 Illumination- defined as the intensity of light per unit per unit area. This is

simply lighting and we are referring to man made lighting. Daylight being

excellent is not included indeed, we assure a night time condition.

8-2 Electric Illumination- is the production of light by means of electricity and its

applications to provide efficient, comfortable and safe vision. When we speak of

lighting design, we refer to only two things;(a) quantity of light &

(b) quality of light


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8-3 Quantity of Light- refers to the amount of illumination or luminous flux per unit

area. It can be measured and handled because it deals with the no. of light

fixtures required for a certain area.

8-4 Quality of Light- refers to the distribution of brightness in the lighting

installation. It deals with essential nature or characteristics of light. It is the

mixture of all items related to the illumination that the quantity of light which

includes several elements such as:

1. Brightness 5. Brightness ration or contrast2. Glare 6. Diffusions

3. Color 7. Aesthetics

4. Psychological reaction & fixtures 8. Economics


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There are four factors that affect illumination:

1. Brightness- is the light that seems to radiate from an object being viewed.

Brightness or luminance is the luminous flux light emitted, transmitted or

reflected from a surface.

2. Contrast- is the difference in brightness or the brightness ratio between and

object to its background. The recommended ratio between an object and the

object being viewed is normally seen 3:1

3. Glare- is a strong, steady, dazzling light or reflection. The quality of lighting

must also include the visual comfort of the system which is the absence of

glare. The excessive luminance and or excessive luminance ratio in the field

of vision is referred as glare.


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There are two (2) types of glare:

1. Direct glare- is an annoying brightness of light in persons normal

field of vision.

2. Indirect or reflected glare- is serious and difficult to control & is

technically glossy object.

i. When the discomfort glare is caused by the light source in the field of vision,

it is known as direct discomfort glare

ii. When the glare is caused by reflection of light source in a viewed surface, it

is called reflected or veiling reflections.


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4. Diffuseness- refers to the control of shadows cast by light. It is the degree to

which light is shadowless and is a function of the no. of directions to which light

collides with a particular point and the comparative intensities.

i. Perfect Diffusion- is an equal intensity of light dashing from all

directions producing shadows

ii. There are three (3) characteristics that defined a particular coloration:

(a) Hue- is the quality attributed by which we recognize and describe

colors as red, yellow, green, violet, and so on.

(b) Brilliance or Value- is the difference between the resultant colors of

the same hue such as white which is most brilliant of the neutral colors whileblack is the least.

(c) Saturation or Chromate- is the difference from the purity of colors,

colors of high saturation must be used in a well lit spaces.

8-5 Estimating Illumination and Brightness


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8 5 Estimating Illumination and Brightness

1-Three types of luminance meter available:

(a) Comparator type- requires the operator to make a brightness

equivalence judgment between the target and the background(b) Direct Reading Type- basically an illumination meter equipped with a

hooded cell arranged to block oblique light.

(c) Accurate laboratory Instrument- this is suitable for fieldwork.

2- Foot Candle (FC)- is the amount of light flux density. It is the unit of measureused when describing the amount of light in a room expressed in lumens per

square foot

(a) Foot candle meter- measured the quantity of light and the degree of

illumination.

(b) Foot Lambert (FL)- defined as the luminance of a surface reflecting,

transmitting or emitting the lumen (lm) of illumination per square foot of area inthe direction of being viewed or the conventional unit of brightness or luminance.

The quantity called Light Flux Density is the common term footcandle (fc)

represented by the formula:


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(b) Foot Lambert (FL)- defined as the luminance of a surface reflecting,

transmitting or emitting the lumen (lm) of illumination per square foot of area in

the direction of being viewed or the conventional unit of brightness or luminance.

The quantity called Light Flux Density is the common term footcandle (fc)

represented by the formula:

Foot candle=Lumens

Area

i. EXAMPLE 1: A 20 watt fluorescent lamp, 120 cm (48 in.) long produces

3,200 lumens of light in a room having a dimension of 10x20 ft. Find the

illumination on the floor.

SOLUTION: Foot candle (fc) = Lumens

Area= 3,200 / m

10x20 ft.

= 16 foot candle


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ii. Rule of thumb 10-30-30 illumination level is here presented:

10 foot candle is adequate for halls and corridors

30 foot candle is sufficient for areas between work stations such as in

offices than desk areas

50 foot candle is satisfactory on spaces where office work is being done

iii. Luminance or brightness of a diffusely reflecting surface is equal to the

product of the illumination and the reflectance.

LUMINANCE = ILLUMINATION x REFLECTANCE FACTOR OR

FOOTLAMBERT = FOOT CANDLE x REFLECTANCE FACTOR

EXAMPLE: Find the luminance if the reflectance factor of the wall is

40% having a foot candle illumination.

Foot lambert = foot candle x Refelectance factor

= 16 x 40%

= 6.4


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3- Lighting Units in Metric Measures

i. In the metric system of measure, the distance is expressed in feet and

the area in square feet. Under the metric system, the distance and the area are

expressed in meters and square meters respectively, thus:

Lumens flux remains in Lux hot

Illumination or light flux expressed in Lux, thus;

Lux = Lumens

Area (sq. m.)

ii. In metric system, luminance or brightness is expressed in Lambert

which is defined as the luminance or brightness of a surface reflecting,

transmitting or emitting one lumen per square centimeter. Millilambert is

conveniently used than the lambert because the value of lambert because the

value of the lambert is greater than that is usually encountered.


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EXAMPLE: A 40 watts x 120 cm. Long fluorescent lamp produces 3,200 lumens

of light in a room having a general dimension of 10 ft x 20 ft. Compute the

illumination on the floor comparing the English and Metric Units.

SOLUTION: BY COMPARISON


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EXAMPLE: Compute the brightness of a fixture with a 1 x 4 plastic diffuser

having a transmittance of 0.6 & illuminated by 2 pieces 3,200 lumens lamp

assuming 100% use of light flux.

SOLUTION:

LUMINANCE = TOTAL LUMENS x TRANSMISSION FACTOR

AREA OF DIFFUSER

= 2 pcs x 3200 x 0.6

1 x 4

= 960 foot lambert


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To obtain metric equivalent

Millilambert = Foot lambert x 1.076

= 960 x 1.076

= 1, 032.96 millilambert

4-Terms, units and conversion factors;

(a) Illumination (E)- intensity of light per unit area.

(b) Light- the energy radiated in the form of luminous flux taht produces

sensation to the eyes .

(c) Lumen 9lm)- unit of luminous flux

(d) Candlepower (l)- the light radiating capability of a light source.

I = - total lumens produced by the lamp

4X(e) Candle or Candela- unit of candle power


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(j) Lux (Lx)- unit of illumination when meter is taken as the unit of length.

lux = lumens 1 foot candle = 10.76 lux

m2

4- Laws of Illumination

a) the illumination on a surface is directly proportional to the luminous

intensity of the illuminating source.

b) the illumination on a surface is inversely proportional to the square of

the distance between the illuminating source and the surface.


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4- Laws of Illumination

a) the illumination on a surface is directly proportional to the luminous intensity

of the illuminating source.b) the illumination on a surface is inversely proportional to the square of the

distance between the illuminating source and the surface

c) the illumination on a surface is directly proportional to the cosine of the angle

made by the normal to the illuminated surface with the direction of the

incident flux.


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c) the illumination on a surface is directly proportional to the cosine of the angle

made by the normal to the illuminated surface with the direction of the incident

flux.

Where Eillumination at point P

lluminous intensity of the light sourceddistance of the light source to point P

hmounting height or distance of the light source from the surface

xhorizontal distance of the light source to point P

angle of incidence

E l A li ht h i dl f 100 d l i h i 10 ft di tl


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Example: A light having a candle power of 100 candela is having 10 ft. directly

above the working table. What is intensity of illumination of a point on the table?

Solution: Since the point of interest is directly above the lamp O = is zero

degree.


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8.6Electrical Lighting Materials:

1. Incandescent Lampmost commonly used lamp. Characteristics are as

follows:a) Cost is cheaper

b) Fast starting and small in size

c) Only 70% of output power is connected to light

d) Sensitive to voltage fluctuations

e) Life span is short

2. Fluorescent Lampone of the commonly used lamp, second to

incandescent lamp.

Characteristics are as follows:

a) For same light output, it consumes lesser energy output

b) Pleasant light output and high efficiencyc) Life span is longer

d) Not sensitive to voltage fluctuations

e) Noisy due to ballast hum


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IXNOTE ON RA 7920


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RA 7920 REPUBLIC ACT # 7920 known as New Electrical Engineering Law

1. Composite of the Board

Board of Electrical Engineering shall be created as a collegial body under thegeneral supervision and administrative control of the Professional Regulation

Commission, hereinafter called the Commission composed of a Chairman

and 2 members to be appointed by the President of the Philippines from

among the nominees of the Commissioner , who were chosen from the

nominees of the Commissioner of the PRC, hereinafter called the

Commissioner, who were chosen from the nominees of the integrated andaccredited association of electrical engineers and allied fields.

2. Power and Duties of the Board:

a) Supervise and regulate the practice of electrical engineering in the Phil.

b) Determine and evaluate the qualifications of the applicants for

registration with or without licensure examination and for special permit.c) Prepare the examination questions and prescribe the syllabi of the

subject and their relative weights for the licensure examinations.

d) Prescribe, amend or revise the requirements for PEE and the subjects

for the licensure examinations for REE & RME and their relative weight

subject for the approval of the Commission.

e) Register successful applicants for PEE and applicants who have passed

the licensure examination for REE and RME and their relative weight


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subject to the approval of the Commission.

f) Look into the conditions affecting the practice of electrical engineering

profession and conduct ocular inspection to places where registrants

practice their profession.g) Promulgate duties and regulations including the code of ethics,

administrative duties, orders and issuances to carry out the provisions of

this act.

h) Investigate violations of the Act and the rules and regulations, Code of

Ethics administrative duties, orders and issuances promulgated by the

Board.i) Issues subpoena to secure the attendance of the respondents or

witnesses or the production of documents relative to the investigation

conducted.

j) Delegate the investigation of the case to the Chairman, a member of the

board or a PRC Attorney.

k) Render decision, order or resolution on preliminary investigation orinquiry and shall become final and executory unless appealed with the

Commission within 15 days from the receipt of the copy.

l) After due notice and hearing, cancel exam results & or bar an examinee

from future examination, refuse or deter his registration; reprimand the

applicant with stern warning, suspend the practice of his profession,

revoke his cert. of registration, to detest his name from the roll of PEEs,

m) To administer oath in connection with the administration, implementation


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of the enforcement of the Act.

n) Submit annual report on the proceedings and accomplishments during

the year and recommendations of the Board to the Commission after the

close of each year.o) Prosecute or institute criminal action against any violation of the Act and

or the rules and regulations of the Board.

p) Adopt an official seal.

q) Coordinate with the DECS in prescribing, amending and or revising the

courses.

r) Prescribe guidelines and criteria on the CPE (Continuing ProfessionalEducation) program for PEEs, REEs, & RMEs and renew their

professional licenses after compliance with the CPE requirements.

s) Perform such other functions and duties as may be necessary to

implement effectively the Act.

3. Qualifications of Board Membersa) Be a natural born Filipino citizen and a resident in the Phil. for at least

five (5) consecutive years.

b) Be at least thirty-five (35) years of age proven integrity with high moral

values in this personal as well as in his professional conduct.


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4. Terms of Service

The members of the Board shall hold office for a term of three (3) years


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from the date of appointment until their successors shall have been

appointed and qualified. Vacancies in the Board shall be filled up by the

President from the list of recommended selected by the Commissioner who

were chosen from the list of nominees submitted by the integrated andaccredited association for the unexpired term only.

5. Removal of Board Member

Any member of the Board may be removed by the President of the Phil.

upon the recommendation of the Commissioner for neglect of duty,

incompetence, malpractice, commission or tolerance of irregularities in the

examination or for unprofessional, unethical or dishonorable misconductafter having been given the opportunity to defend himself to a proper

administrative investigation.

6. Executive of the Board

The Commissioner of the PRC shall be the executive officer of the board

and shall conduct the examination given by the board.

7. Holding of ExaminationsExaminations for the practice of electrical engineering in the Phil. Should be

given twice a year in the City of Manila and other places on dates the Board

may recommend for determination of scheduling. The qualified applicants

for examination, notice of examination shall be issued not later than ten

(10) days prior to the first day of examination.

8. Qualifications of Applicants for Registered Master Electrician


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Examination

Any person applying for admission to the registered master electrician

examination as here in provided shall establish the satisfaction of the

Board that on or before the date of the date of examination, he possessesthe following qualifications;

a) He is a citizen of the Philippines

b) He is at least eighteen (18) years of age.

c) He is of good reputation with high moral values.

d) He is not been convicted by the court of an offense involving moral

turpitude.e) He has any of the following technical backgrounds.

1. He has completed at least three (3) years of a five year Bachelor

of Science in Electrical Engineering (BSEE) program or three-year

course in Electrical Engineering technology from an engineering

school recognized by the Phil. Government and in addition has a

subsequent specific record of one (1) year practice in electricalwiring & installation, operation & maintenance of utilization

devices & equipment or

2 Has graduated from a two year electrician course of instruction from


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2. Has graduated from a two year electrician course of instruction from

a vocational or trade school recognized by the Phil. Govt & in

addition has at least two (2) years of apprenticeship after the

completion of the course of instruction on electrical wiring &

installation , operation & maintenance of utilization devices and

equipment, or

3. Has completed a one (1) year electrician course of instruction from

a vocational or trade school recognized by the Phil. Govt & in

addition has at least three (3) years of apprenticeship record of at

least five (5) years of apprenticeship in electrical wiring &

installation, operation & maintenance of utilization devices and

equipment.

9 Report of ratings:


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9. Report of ratings:

The board of Electrical Engineering shall within one hundred fifty (150) days

after the date of completion of the examinations, report the ratings obtained

by each candidate to the Commission.

10. Re-examination of Failed Subjects:

An applicant shall be allowed to re-take any number of times only on the

subjects in which he has obtained a grade below fifty percent (50%). When

he obtains an average of 70% percent in the subjects repeated, he shall be

considered to ahve passed his licensure examination.

11. Oath

All successful candidates in the examination shall be required to take

professional oath before the board or any government official authorized to

administer oaths prior to the practice of REEs, PEEs, RMEs.


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XPREVIOUS RME EXAMINATIONS

MULTIPLE CHOICE TYPE TESTS

A. APRIL 1994 RME

1. A 6 volt lead-acid battery has an internal resistance of 0.01 ohm. How much

current flow if the battery has a short circuit?

A. 60 A

B. 600 A

C. INFINITYD. ZERO

ANSWER AND SOLUTION

B. 600 A


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2. An AC series circuit has a resistance of 6 , an inductive reactance of 10

and a capacitive reactance of 18 . What is the circuit power factor?

A. 0.6 leadingB. 0.8 lagging

C. 0.6 lagging

D. 0.8 leading

ANSWER AND SOLUTION

A. 0.6 Leading

Given:

R = 6

= 10

= 18 Pf = ?


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3. A binary alloy of copper and zinc.

A. Bronze

B. BrassC. Alnico

D. Steel

ANSWER AND SOLUTION

B. Brass


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2. A meter whose needle is initially at the center.

A. Dynamometer

B. Iron Vane Meter

C. GalvanometerD. Voltmeter

ANSWER: C. Galvanometer


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C. October 1996 RME / October 1995 RME

1. Automatic device that operates at present values is known as

A. RelayB. Mercury switch

C. Contactor

D. Fuse

ANSWER: A. Relay


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3 At starting the motor current is high due to


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ANSWER: B. Counter emf is zero

3. At starting the motor current is high due to

A. Counter emf is high

B. Counter emf is zero

C. Supply voltage is highD. Armature circuit resistance is open

D RME April 1996


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ANSWER: C. 125 watts

D. RME April 1996

1. Two resistors of resistances of 5 and 7 are connected in series

across a 60 volt source. What is the power absorbed by the 5 resistor?

A. 50 watts

B. 25 watts

C. 125 watts

D. 100 watts


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2. Shunt generators are most suitable for parallel operation due to their

________

A. Constant voltage characteristics

B. Dropping voltage characteristicC. Increasing voltage characteristics

D. Variable voltage characteristics

ANSWER: B. Drooping voltage characteristics


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E. April 1995 RME

1. In concealed knob and tube wiring, the clearance to be maintained between

conductors is:A. 66 mm

B. 45 mm

C. 76 mm

D. 800 mm

ANSWER: C. 76 mm


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2. A run of type 1 GS cable between pull boxes or terminations shall not contain

more than the equivalent of ______________ quarter trends.\

A. One

B. TwoC. Three

D. Four

ANSWER: D. four


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3. For optional in dwelling units, the first 10 kw shall be computed at 100% while

the remainder is at _______.

A. 65%

B. 60%C. 50%

D. 40%

ANSWER: D. 40%

F RME O t b 1996


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F. RME October 1996

1. In resistance color coding, red color is assigned to a value?

A. 3B. 0

C. 2

D. 1

ANSWER: C. 2


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G RME O t b 1995


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G. RME October 1995

1. An electric iron takes 3 Amps. If the heating element has a resistance of 40

, what is the power consumption?A. 0.45 KW

B. 0.49 KW

C. 0.35 KW

D. 0.51KW

ANSWER: B. 0.49 KW

2 A th f d ll


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2. Another name for secondary cell.

A. Wet cell

B. Storage cell

C. Dry cellD. Disposable cell

ANSWER: B. Storage cell

3 T i t f 8 d 10 h ti l t d i ll l &


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3. Two resistance of 8 and 10 ohms respectively are connected in parallel &

make a total current of 9A. What is the current flowing in the 8 resistance?

A. 5A

B. 4AC. 6A

D. 3A

ANSWER: A. 5A

4 A 50 F capacitor has a reactance of 53 05 at a frequency of


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4. A 50 F capacitor has a reactance of 53.05 at a frequency of

A. 80 Hz

B. 50 Hz

C. 70 HzD. 60 Hz

ANSWER: D. 60 Hz

5 What resistance must be connected across a 4 resistor in order to give an


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5. What resistance must be connected across a 4 resistor in order to give an

equivalent resistance must be connected across 4 resistor in order to give

an equivalent resistance of 3 ?

A. 10 ohmsB. 9 ohms

C. 12 ohms

D. None of these

ANSWER: A. 12 ohms

6 A high resistance connected in parallel with a potential relay across 120 V


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6. A high resistance connected in parallel with a potential relay across 120 V

battery will:

A. Increase in the current through the relay

B. Increase the voltage through the relayC. Have no effect on the relay

D. Make the relay inoperative

ANSWER: C. Have no effect on the relay

7 Three capacitors of 5 10 and 15 F respectively are connected end to end


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7. Three capacitors of 5, 10 and 15 F respectively are connected end to end.

Find the equivalent capacity of the combination.

A. 2.73

B. 30 C. 5.23

D. None of these

ANSWER: A. 2.73 F

H RME April 1995


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H. RME April 1995

1. How is a voltmeter connected in a circuit?

A. Connected in short circuit across the loadB. Connected in shunt across the load

C. Connected in series across the load

D. Connected in open circuit with the load

ANSWER: B. Connected in shunt across the load

2 Component of an atom that doesnt have electrical charge?


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2. Component of an atom that doesn t have electrical charge?

A. Electron

B. Proton

C. NeutronD. None of these

ANSWER: C. neutron

3 A lead-acid cell is connected in multi plate for the purpose of


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3. A lead-acid cell is connected in multi plate for the purpose of

A. Increasing the emf of the cell

B. Increasing the capacity of the cell

C. Increasing the internal resistance of the cellD. All of these

ANSWER: B. Increasing the capacity of cell

4 An ohmmeter consists of a meter movement in series with


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4. An ohmmeter consists of a meter movement in series with

A. Inductor

B. Spring

C. CapacitorD. Battery

ANSWER: D. Battery

5 The resistance reading of a shorted capacitor is


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5. The resistance reading of a shorted capacitor is

A. High

B. Zero

C. InfinityD. Low

ANSWER: B. Zero

6 In a large alternator which of the following is negligible?


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6. In a large alternator, which of the following is negligible?

A. Reactance of winding

B. Resistance of winding

C. Impedance of windingD. None of these

ANSWER: B. Resistance of winding

7 A phenomenon in a series AC circuit wherein a maximum current will flow


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7. A phenomenon in a series AC circuit wherein a maximum current will flow

A. Avalanche

B. Resonance

C. Break-evenD. Breakdown

ANSWER: B. Resonance

8. A measuring instrument used to measure the diameter of circular wires in mils.


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8. A measuring instrument used to measure the diameter of circular wires in mils.

A. Micrometer

B. Millimeter

C. Wire gaugeD. Milliammeter

ANSWER: D. Micrometer


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2. The resistance of a coil of wire is 1 K at 20C. If the coil is immersed into an


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2. The resistance of a coil of wire is 1 Kat 20 C. If the coil is immersed into an

oil, the resistance falls to 880 . If the wire has a temperature coefficient of

0.006 at 20C. How much is the temperature of the liquid?

A. 0CB. -20C

C. 17.6C

D. None of these

ANSWER: A. 0C

3. Power factor is defined as the ratio of:


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A. Watts to volt-amps

B. Volt-amps to reactive volt-amps

C. Watts to active volt-ampsD. Volt-amps to watts

ANSWER: A. Watts to volt-amps

4. Electrons in the last orbit of an atom are called


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A. Bound electrons

B. Free electrons

C. Valence electronsD. Charged electrons

ANSWER: C. Valence electrons

3. Power factor is defined as the ratio of:


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A. Watts to volt-amps

B. Volt-amps to reactive volt-amps

C. Watts to active volt-ampsD. Volt-amps to watts

ANSWER: A. Watts to volt-amps

5. A 400 MCM cable has 37 strands, what is the diameter of each strand in mils?


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A. 10.81

B. 1081

C. 104D. 108

ANSWER: C. 104

J. RME October 1996


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1. If the two leads of a DC series motor are reversed, which of the following

events will happen?

A. Becomes a generatorB. It turns in the same direction as before

C. It will not run

D. It will run in the reversed direction

ANSWER: D. It will run in the reversed direction

2. Copper field coils of a motor was measured at 21C & found to have


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resistance of 68 . After the motor has run for a given time, the resistance is

found to be 50 . What is the hot temperature of the winding?

A. 106.36C

B. 106.30 C

C. 103.66 C

D. None of these

ANSWER:C. 103.66 C

3. The continuity of a coil of winding maybe determined by measuring the


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resistance of the coil. If the resistance measured is infinite, the coil winding is

A. Open

B. Perfect conditionC. Partially shorted

D. Totally shorted

ANSWER:A. Open

4. A secondary cell is charged with a constant current of 10A for 10 hours. How


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much charge is accumulated?

A. 100 coulombs

B. 360, 000 coulombsC. 100, 000 coulombs

D. 60, 0000 coulombs

ANSWER: B. 360, 000 coulombs

6. A cell whose emf is 1.45 V has an internal resistance of 4 . What current will


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flow, if this cell is connected across 1resistor?

A. 4A

B. 2AC. 5A

D. 0.3A

ANSWER: D. 0.3A

7. Another name for full voltage starting?


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A. Reduce voltage starting

B. Full load starting

C. Direct on-lineD. Starting without a contractor

ANSWER: C. Direct on-line

8. What is the neutral current of a 4-wire, 3 phase circuit if line A carries 50A, line


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B carries 50A, line C carries also 50A?

A. 50 A

B. 86.6 AC. 0 A

D. 16.57 A

ANSWER: C. 0 A since the three line currents are equal

9. What is the amperage of a 120 V, I phase circuit taht supplies a load of 3.12


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kVolt-amperes?

A. 26 A

B. 30 AC. 22 A

D. 15 A

ANSWER: A. 26 A

K. Philippine Electrical Code


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1. The maximum electrical trade size of intermediate conduit is?

A. 150mmB. 125mm

C. 200mm

D. 100mm

ANSWER: D. 100mm

2. Before starting and installation works, alteration, repair or extension on any

l t i l t h t t f it i i d?


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electrical system, what type of permit is required?

A. Building permit

B. Working permitC. Electrical permit

D. Mayors permit

ANSWER: C. Electrical permit


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L. RME October 1995 (PEC)


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1. Equipment for installation in hazardous locations must be tested and

approved for use according to the classification of hazardous involved.These are divided into ____groups.

A. 4

B. 3

C. 7

D. 6

ANSWER: B. 3

2. Individual branch circuits using type FCC (Flat Conductor Cable) that have

ti t di


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ratings not exceeding ____________.

A. 20 A

B. 30 AC. 15 A

D. 40 A

ANSWER: A. 20 A

3. Which of the following conductors is applicable for underground service

entrance cond ctors?


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entrance conductors?

A. Type THWN

B. Type UFC. Type M

D. Type USE

ANSWER: D. Type USE

rmse lecture

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