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Department of Technical Education Andhra Pradesh

NameDesignationBranchInstituteYear/SemesterSubjectSubject CodeTopicDurationSub Topic

Teaching Aids

: P. Balanarsimlu: Lecturer: Electrical Engineering: Govt. Polytechnic Nizamabad: VI Semester: Electrical Utilisation and Traction: EE605 A: Electric Lighting : 100 Mins: Types of Lamps, Glare, Requirements of Good Lighting: PPT, Diagrams. Animation

Revised By : K. Chandra Sekhar, L/EEE, GPT, HYD

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Recap

In the last class you have learnt about

• Units of Wave Length

• Definitions of Plane angle and Solid angle

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Objectives

On completion of this topic you would be able to know about

• Applications of lamps for different situations

• Domestic, Industrial, Decorative, Advertisement, Street lighting and Flood lighting

• Phenomenon of glare

• Requirements of good lighting

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Types of Lamps

Lamps are classified into

• Incandescent lamps

• Arc lamps

• Discharge lamps

Sodium vapour lamps

Mercury vapour lamps

Fluorescent lamps

Neon lamps

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Lamps For Different Situations

1) Domestic Lighting

• The requirements of illumination varies from place to place, such as study room, drawing room, bedroom, verandah and toilets etc

• Incandescent lamps ,fluorescent lamps, compact fluorescent (CFL) lamps are well suited for domestic lighting

Lamps For Different Situations

2) Industrial Lighting

• Sufficient light in Industries increases the production , quality of work and reduces the accidents

• An illumination of about 200 lux is required to obtain day light

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Lamps For Different Situations

• Incandescent, fluorescent,CFL and mercury vapour lamps

are suitable for industrial lighting

• The lamps should be mounted at sufficient height to

provide uniform illumination without any glare

• In case of Traveling crane, side lights with deep

reflectors should be provided

• Machine shops are usually provided with general and

local lighting

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Lamps For Different Situations

3)Decoration Lighting• Decorative lighting is provided in functions and tourist

places, such as Lord Venkateshwara temple, Taj mahal, Golden temple, Brindavan gardens, etc

• MV lamps, SV lamps ,incandescent, fluorescent, halogen, series and neon lamps are used for decoration purpose

• MV lamps play an important role in decorative lighting

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Lamps For Different Situations

4) Advertisement Lighting

• This type of lighting is used to attract the public and to

increase the sales

• Dress materials, signboards, cosmetics, automobiles,

road junctions, public places and domestic appliances

etc. comes under this category

• Almost all types of lamps with reflectors are used for

advertising lighting

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Lamps For Different Situations

5) Street Lighting

• The purpose of street lighting is to promote safety and

convenience to pedestrians, vehicles, police supervision

and other purposes

• The high illumination is required on traffic roads and

shopping centers

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Lamps For Different Situations

5) Street Lighting

• The light should be directed downwards from the lamp by suitably designed reflectors

• MV ,SV, Fluorescent and Incandescent lamps are used for street lighting

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Lamps For Different Situations

6) Flood Lighting• It is the night time lighting of exterior areas such as open

area of an industry, railway yards, sports stadiums, quarries and temples

• Flood lighting to parks, gardens,lakes,flower beds, buildings and ancient monuments should enhance the beauty and attract the public

• M.V.lamps,S.V.lamps and Halogen lamps with water tight reflectors are used for flood lighting

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Illumination of Different Practical Sources

• summer mid day, in open cloudless sky = 1,00,000 lux

• summer mid day under a balcony = 2000-3000 lux

• summer behind a window = 1000-3000 lux

• winter mid day, in open cloudless sky = 10,000 lux

• Sunrise and sunset = 500 lux

• Full moon and bright sky = 0-25 lux

Glare

• Glare is defined as unwanted light

• It is also defined as the light over and above that

required for the performance of a visual task under most

comfortable viewing conditions

• If the human eye is exposed to a very bright light, the pupil (dark circular opening in the center of the iris of the eye ) contracts in order to reduce the amount of light admitted and prevent damage to the retina . This phenomenon is known as glare

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Glare

• It is well familiar in connection with vehicle headlights

• If a lamp with out reflector is mounted at a very less height

from the floor, causes glare

• Glare is also caused when high power lamp or high

shining objects are seen

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Need of Good Lighting

• Good lighting makes seeing easy and comfortable . Visual comfort increases the efficiency of a workman

• When light is too dim ,we can’t observe the objects properly. On the other hand, if light is too bright, we feel strain to open the eye lids

• If the eyes are opened by force, the water comes out and it makes seeing uneasy and discomfort

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Requirements of Good Lighting

1) Illumination Level

The visibility of the object depends on the level of illumination, which in turn depends on the

• State of object

• Size of object

• Period of observation

• Colour of object

• Background contrast

Requirements of Good Lighting

ii) Uniformity of Illumination

• The human eye adjusts itself automatically to the

brightness within the field of vision

• If there is a lack of uniformity ,the iris of eye has to adjust

more frequently and causes fatigue to the eye

• For uniform illumination general and local lighting with

brightness ratio not greater than 3:1 is to be provided

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Requirements of Good Lighting

iii) Absence of Glare

• The glare should be avoided

• Light sources should be mounted above the normal line

of sight

• By using diffusers and reflectors glare can be reduced

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Requirements of Good Lighting

iv) Colour of Light• The Colour of the incident light effects the appearance of

the object Colour

• The composition of the light should be such that the Colour appears is natural and makes no difference from that under light

• S.V. and M.V. lamps produce Colour distortion, can be used in street lighting

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Requirements of Good Lighting

V) Shadows

• Long and hard shadows should be eliminated because

they cause fatigue on eyes

• complete absence of shadows is not an ideal lighting,

dull shadows are necessary to give the three

dimensional view of any object

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Requirements of Good Lighting

vi) Contrast

• The local lighting should be supported by general

lighting, otherwise it causes strain on the eyes

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Summary

So far we have discussed about

• Applications of lamps for different situations

• Domestic , Industrial, Decorative, Advertisement, Street lighting and Flood lighting

• Phenomenon of glare

• Requirements of good lighting

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Quiz

1.A poor man for his kitchen lamp _____ is used

a) S.V. lamp

b) M.V. lamp

c) Incandescent lamp

d) Fluorescent lamp

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Quiz

2) Glare is reduced by

a) increasing the mounting height of the lamp

b) using diffusers

c) using reflectors

d) all of the above

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3) An illumination of about ----- lux is required to obtain day light

a) 20

b) 300

c) 200

d) 100

Quiz

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4) when ___________ light enters in to the iris closes to

protect the retina of the eyes

a) dim -light

b) bright light

c) medium light

d) none

Quiz

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Frequently Asked Questions

1. State the requirements of good lighting

2. What is glare? how it can be minimized?

3. Explain domestic and industrial lighting

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THANK YOU

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