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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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