TRACTION

TRACTION

HISTORY OF ELECTRIC TRACTION :-

👉 4500-3300 BC (Copper Age): creation of the potter's wheel; earliest strong

      wooden wheels (circles with an opening for the hub); earliest wheeled

      vehicles; training of the pony

👉 2200-1550 BC (Center Bronze Age): creation of the spoked haggle

       the chariot

👉  In 1769 the primary steam-controlled vehicle equipped for human transportation

       was worked by Nicolas-Joseph Cugnot.

👉 In 1803, Hayden Wischett planned the main vehicle controlled by the de Rivaz

      motor, an early gas powered motor that was filled by hydrogen.

👉 Marcus made the two-cycle burning motor.

👉 The vehicle's second manifestation in 1880 presented a four-cycle, gasolinepowered motor, a                   cunning carburetor plan and magneto start. He made two extra models further refining his plan               with guiding, a grasp and a brake.

 

👉  Development of the gas (petroleum ) energized gas powered motor in the 1880s.

👉 The four-stroke petroleum gas powered motor that actually comprises the

      most predominant type of present day car drive was protected by Nicolaus Otto.

👉 The comparative four-stroke diesel motor was imagined by Rudolf Diesel.

👉 1803 - First open railroad was made in London. It moved products through strength on the line that          was 14 km long.

👉  1804 - British chap Matthew Murray made first steam based train in Leeds.

👉 1812 - First business traveler rail line opens in Britain on the Middleton Rail line.

👉 The battery electric vehicle owes its starting points to Ányos Jedlik, one of the  innovators of the             electric engine, and Gaston Planté, who designed the lead-corrosive battery in 1859.

👉  In1881 First open electric cable car line opened in Berlin.

👉 In 1882 the Italian Enrico Bernardi made the principal petroleum controlled vehicle, a

       tricycle.

👉 1890 - London underground trains changed to electrical motors, beginning the

        time of present day quick travel frameworks.

👉 1913 - Diesel fueled trains began being utilized in Sweden.

👉 1937 - German innovator Hermann Kemper licensed train framework that utilized

       attractive levitation (maglev).

VARIOUS SYSTEMS OF TRACTION

💥Traction is the activity of drawing or pulling something over a surface,

     particularly a street or track.

💥"a crude vehicle utilized in creature footing"

💥Rationale power gave to draw or pull something, particularly on a railroad.

      Drive of vehicle is known as the foothold and the framework that causes the

       impetus of a vehicle in which that main thrust or tractive power is

       gotten from different power and gadgets, for example, Muscle power driven Foothold

       frameworks, electric engines, steam motor drives, petroleum motor drives, diesel

        motor jumps, Battery controlled drives, Attractive levitation and so on. Is known as

        foothold framework.

IDEAL TRACTION SYSTEM

💢Traction High beginning tractive exertion to have quick speed increase.

💢Independent and smaller train so it very well might have the option to run on any

      defeat.

💢 Hardware fit for enduring huge transitory over-burdens.

💢Least wear on the track.

💢Slowing down ought to be to such an extent that base wear is caused on the brake shoes, and

      assuming that conceivable the energy ought to be recovered and gotten back to the inventory.

💢Hardware required ought to be least, high proficiency, low starting and

      support cost.

💢 No impedance to the correspondence line running along the track.

💢 Simple speed control.

💢 It ought to be without contamination.

DIFFERENT SYSTEM OF TRACTION

🧿Traction Systems using muscles Power : 

    🎯Animal driven : Bullock cart , Horse cart , Sledge etc.

     🎯Manual driven : Cycle, Rickshaw, cycle van etc. 

🧿Traction systems using motive power: 

   🎯Non-electric Traction System 

    🎯Direct Steam Engine Drive 

    🎯Direct Internal Combustion Engine Drive

🧿 Electric Traction System 

       🎯Steam Electric Drive 

        🎯Internal Combustion Engine Electric Drive 

                             ● Diesel electric traction 

                             ● Petrol electric traction 

        🎯Battery Electric Drive 

        🎯Electric Traction Drive 

        🎯Electro-Magnetic levitation system.

Neon Lamps

Neon Lamps

what is neon lamp ?

A neon lamp is a particular kind of gas discharge lamp that burns low pressure mixtures of neon gas and other gases like argon or helium.

The gas inside the lamp is ionised and emits light when an electric current is introduced to it.

Neon lamps were invented at the beginning of the 20th century, and by the middle of the century, they were widely used for exhibits and signs.

They are still utilised in modern times for both decorative lighting and technological gadget indicators.

The color of the light emitted by a neon lamp depends on the gas mixture and the voltage applied.

Whereas argon emits a blue-violet light, neon emits a vivid red-orange light.

By adjusting the gas mixture and voltage, a variety of colors can be produced.

💥 It is cold cathode lamp 

💥 Operating voltage is low – 110 V AC or 150 V DC 

💥 It consists of glass envelope with electrode and filled with Neon gas along with small amount         of  Helium 

💥 Gives Orange – Pink radiation 

💥 By varying the composition of glass and adding different substances different colours (like             O,R,G,Y) etc. Can be produced. 

💥 Efficacy varies from 50 Lu/W (Red) to 65 Lu/W (Green).

💥 Normally used as indicators, night lamps, determination of DC polarity etc.

Neon Sign Tubes

💢 The length of the lamp may be varied (up to nearly 9m.) and even may be bent in any desired         shape. It is called Neon Sign Tube. 

💢 Comparatively higher operating voltage 

💢 Starting Starting purpose purpose striking striking value is nearly 1.5 times 

💢 Step up transformer with high leakage reactance is used for starting voltage. Drooping                  characteristics helps in reduced running voltage. 

💢 Sometimes UV radiation and Fluorescence principle is used. Hence called Cold Cathode                 Fluorescent Lamp (CCFL) 

💢 Mainly used in advertising and decorative purposes.

Colorimetry

 Colorimetry

Colour

👉Variety is a quality not entirely settled by the light's unearthly structure and the communication with the natural eye. Subsequently, variety is a psychophysical

peculiarity, and impression of variety is emotional.

👉The cone cells are gathered into three kinds, each answers a piece of the

range, with top reactions comparing to blue, green, and red light. The

cooperation of these gatherings is then answerable for the boost which is deciphered by the mind as variety.

👉At the point when a variety is made freely like by a light, is called source

variety.

👉For object tone, it is important to decide and assess the ghastly dissemination of the illuminant. This is on the grounds that the variety shows up distinctively when the

light source changes.

Colorimetry

🧿 Colorimetry, the study of variety estimation, is generally utilized in commerce, industry and the             lab to communicate variety in mathematical terms andto measure variety contrasts between                      examples. Applications incorporate paints, inks, plastics, materials and attire, food and drinks,             drugs and cosmetics, shows, and different parts and items that reflect or communicate variety.

🧿 The resultant variety impact of blending three shaded lights, red, green, and blue. The red, green,           and blue can be known as the primaries and the subsequent yellow, cyan, and fuchsia the                         secondaries. Source Tone is of addititive blending nature. • The shade of a still up in the air by               colors. These are synthetics which make a given tone by deducting (retaining) portions of the                 range  of the occurrence light. The leftover light is reflected and this gives the item its variety                 trademark. Object tone is of subtractive nature.

  

🧿The properties of variety which are intrinsically discernable by the natural eye are shade,                        immersion  and splendor. • It is found that a wide range of mixes of light frequencies can create a          similar view of variety. This can be placed in context with the CIE chromaticity graph.

CIE chromaticity diagram

Colorimetric instrument 

💢 A tristimulus colorimeter gauges the tristimulus upsides of a variety. 

💢 irrefutably the ghastly power conveyance of a light source can be estimated with

      a spectroradiometer. 

💢 Reflected variety can be estimated utilizing a spectrophotometer.

💢 A spectrocolorimeter is a spectrophotometer that can is a spectrophotometer that can work out                compute tristimulus values.

Colour rendering index (CRI)

💥A variety delivering record (CRI) is a quantitative proportion of the capacity of a light source                 to reveal  the shade of different items steadfastly in correlation with an ideal or normal light source           (typically we  consider as sunshine.). Light sources with a high CRI are alluring in color-basic               applications like     activity theater and workmanship reclamation.

💥It is characterized by the Worldwide Commission of Enlightenment (CIE) as follows:

     Variety delivering: Impact of an illuminant on the variety appearance of items by cognizant                     or subconscious subliminal correlation examination with their variety appearance under a reference         illuminant. 

💥The variety delivering record (CRI) is estimated as a number with greatest worth 100.                              The minimum  worth might be even negative ( if there should be an occurrence of LPSV light).              Under light of low CRI lamp, all objects seem to be same in variety (blackish Grey).A CRI of 100          shows the real nature of the object. Brilliant and incandescent lamp sources have a CRI of 100 or             almost 100.

💥Related variety temperature of a light source (CCT) : It is the outright temperature of a blackbody           whose chromaticity most almost looks like that of the light source. If chromaticity precisely                     coordinates with any worth on the dark body radiator, then, at that point, it is named as Colour                Temperature (CT). In reality CCT is the general term used to depict variety character of any light             source.

Metal Halide Lamp

 Metal Halide Lamp

A specific type of high-intensity discharge (HID) lamp known as a metal halide lamp produces light by using a combination of metal halide salts.

The metal halide salts and other gases are contained in a tube that the lamp employs to generate light by circulating an electric current through it.

Contents:

💢 Theory of Operation of Metal Halide lamp 

💢 Characteristics & Application of Metal Halide Lamp 

💢 Development of CDMH Lamp

Metal Halide Lamp: Working Principle

💥A metal halide lamp can be considered as an extension of HPMV lamp.

💥In HPMV lamp visible radiations are at 3 spectral areas ; Blue (436nm), Green(546nm) &                       Yellow(578nm). Red region is absent. It causes poor colour renditionproperty and moderate                    luminous efficacy. 

💥By adding suitable suitable metals with lower excitation excitation potentials potentials to the arc            tube, thecolour property i.e. CRI can be improved. 

💥Metals may be of different types – Single Line radiators ( Sodium – Yellow, Indium – Blue), Multi          Line Radiators (rare earth maetals like Scandium, Thorium, etc), Molecular Radiators for wide              band light emissions. 

💥 But they are generally highly reactive and would damage the quartz arc tube. 

💥By adding the metals in the form of halides these problems can be eliminatedto a satisfactorily               good   extent. 

💥Iodides (less reactive) are mostly used & Fluorides never used (Strong reactive)

Working Process

≽ At first the output spectrum is only due to Hg Vapour, because Halides remainsolidified. 

≽ On further heating Halides dissociate in the hot central regionof thedischarge tube allowing their            metal atoms to make a contribution to the lightoutput by their characteristic spectral emission                mostly  in the Red region. 

≽ In the relatively cool region near arc tube wall, metal and halogen atomsrecombine to form the              halides again. These halides are much less chemicallyreactive than the metal ions and hence cause          less damage to the fused silica(quartz) glass of arc tube. 

≽ This cyclic process results efficient lamp operation with better CRI.

≽ The radiation Characteristics of MH lamps are strongly dependent of thevapour pressure of the              halides and hence the Cold and Hot spot temperaturesof the arc tube

Optical Characteristics and Applications

👉 MH lamps can be made in various size and rating and with different colour output – from Daylight         to even UV. 

👉 With varying composition of Metal Halides and inside pressure, MH lamps are available with                 variable optical properties - 

👉 Luminous Efficacy – 70 -100 Lm/W 

👉  CRI – 70 -90  CCT – 3600 K – 5600 K 

👉 Life – 6000 – 15000 working hours 

👉 Application – Quality Interiors, Wide Area Floodlighting, Stage and Studio Light, Sports Light               particularly for Colour TV Broadcasting.

Ceramic Discharge Metal Halide lamp (CDMH)

🧿Major criticism to the MH lamp is - poor lamp to lamp colourconsistency (less uniformity) and             changes in colour through out the life(lack of stability) 

🧿Ceramic Discharge Lamp is recent development to solve the issue to asatisfactory extent. 

🧿Ceramic Ceramic can withstand withstand higher temperatures temperatures than quartz glass.                Thispermits higher wall temperatures thereby evaporating more of themetal halide salts into the             gas  arc and allowing for more efficient use ofthe chemicals. Ceramic lamps offer improved                    luminous efficacy    andcolour rendering as a result. 

🧿Normally Poly Crystalline Alumina (PCA) is used. 

🧿However, in contrast to silicon, aluminum hardly dissolves in tungstenand the reaction with rare              earth elements are much more self limiting. 

🧿But there is a colour shifting in output from Quartz to Ceramic Tube

Mercury Vapour

 Mercury Vapour

A mercury vapour lamp is a particular kind of high-intensity discharge (HID) lamp that emits illumination using mercury vapour.

When an electric current is run through a tube holding mercury vapour and other gases, the mercury atoms become excited and emit ultraviolet light.

This is how the lamp operates.The lamp's interior phosphorescent coating is then activated by the ultraviolet light, which causes it to produce visible light.

Contents:

👉 Theory of Low Pressure Mercury Discharge 

👉 Low Pressure Mercury Vapour UV lamp : Working & Application

👉 Construction of High Pressure Mercury Vapour Lamp 

👉 Working Process of High Pressure Mercury Vapour Lamp

 👉 Characteristics & Application of High Pressure Mercury Vapour Lamp

Low Pressure Mercury Discharge

💢Mercury Has Different excitation level 

💢Electrical discharge in Low Pressure Mercury Vapour is mostly(typically 63%) converted into

     UV-C  radiations -Two resonanceradiations radiations are at 253.7 nm & 185 nm 

💢Approximately 3% is converted into visible radiations –predominantly at 405 nm (Violet), 436 nm          (Blue), 546 nm(Green) & 578 nm(Yellow). The overall effect of the mixture isa discharge of Pale            Blue colour light, but obviously with verysmall efficacy. 

💢The remaining Input energy is dissipated as heat radiations.

Low Pressure Mercury Vapour UV Lamp 

High Altitude The most common application of mercury discharge is in fluorescent lamps, which produce visible radiation using the fluorescence principle.

To convert UV radiation into visible light, the lamp's interior wall is coated with phosphor.

💥Fluorescent Lamp will be discussed in details in the next module.

💥But Low Pressure Pressure Mercury Mercury Vapour Lamp without without any                                     phosphorphosphorcoating producing UV Rays, are also used in some specific fields.

UV Lamp Application

⋙ UV lamp finds its application as germicidal or Ozone absorption lamps. UVis also essential for                Chromatography, Photochemistry, Calibration of UVDetectors, Calibrations of                                      Spectrophotometer, and more. 

⋙ UV-C light is germicidal – it deactivates the DNA of bacteria, and otherpathogens and thus                   destroys  their ability to multiply and cause disease. UV-C germicidal lamp has its application in              medical sector (pharmaceutical production, laboratories, hospitals and clinics) Water purification,           Industryand Food Processing 

⋙UV also attracts insects and flies. So UV lamps are also used in electricinsect killer. A light source        (emitting UV and blue visible radiations) attractsinsects to an electrical grid, where they get fatal            electric shock by touchingtwo wires with a high voltage between them. It is housed in a                           protectivecage to prevent human and larger animals to touch the high voltage grid.

High Pressure Mercury Vapour Lamp : 

Construction

⋟ Normally operated vertically. 

⋟ Inner Arc Tube - hard glass i.e quartz in order to withstand high temperature 

⋟ It consists of Tungsten electrodes, Mercury and small amount argon gas. 

⋟ Outer glass (Elliptical shape) - Soda-Lime silicate silicate glass and for higher rating Borosilicate           glass. 

⋟ Space between inner & outer glass tube - completely or partially evacuated to reduce convection             heat  loss. 

⋟ For cold start an auxiliary electrode - molybdenum or tungsten positioned close to one of the main           electrode, but connected to the opposite supply polarity through a limiting carbon resistor of 10-30        KΩ

HPMV Lamp : Working Principle

⇛ Argon (Filling gas) pressure – 2500-5000Pa, Mercury dose 18 to 36 mgdepending on the lamp               rating. 

⇛Initially supply is in between main and auxiliary electrode resulting dischargethrough argon –                reddish   radiation. 

⇛ After some time Hg is vaporised, ionisation and discharge of Hg starts.

⇛After complete vaporisation of Hg, a low resistance path is created betweentwo main electrodes              electrodes and the arc is shifted shifted to main electrodes electrodes.

⇛ Auxiliary electrode along with the limiting resistance becomes inactive. 

⇛ When fully run up the lamp operates at 1 to 2 Atmosphere. For higher pressurefurther spectrum               broadening is achieved generating more white light .

⇛ Due to increased pressure comparatively broad spectrum is developed andhence bluish white                  radiation together with UV, but it is deficient at Red end ofthe spectrum.

⇛ The phosphor coating on the inner wall of the outer envelop increases thelamp efficacy by                       converting UV into Red Light (600-750nm). Colour renderingproperty is also improved.

HPMV Lamp: Electrical & Optical Characteristics and Application

🧿Operating Voltage – Supply Voltage 

🧿Operating Temperature – 600˚C

🧿Power rating – 80 – 1000 W 

🧿Takes 4-5 min for full brilliance 

🧿Colour – Bluish White

🧿Life – 10000-24000 working hours 

🧿CRI (Typical (Typical 250 W) – 16-20 (Clear Bulb) & 40- 50 (Phosphor Coated)

🧿CCT (Typical 250 W) – 6000 K (Clear Bulb) & 3800 K (Phosphor Coated) 

🧿Luminous efficacy – 35-65 Lm/W

 🧿Application – High ceiling manufacturing bay, Railway Yard, Airport, Shopping Centre, Stage,               Sports Lighting etc. 

🧿After damage of lamp, disposal of mercury is another problem - health hazardous

🧿Now a days almost obsolete due to poor efficacy and CRI.

Halogen Lamp & Gaseous Discharge Lamps

 Halogen Lamp

👉 Small-scale halogen (preferably iodine) vapour addition to the pressing gas

👉It uses a chemical process known as the regenerative cycle to restore some of the evaporated                    tungsten vapour to the filament.

👉Tungsten + Iodine = Tungsten Iodide 

👉Thermal breakdown of Tungsten Iodide near the filament at higher temperature results in deposition        of tungsten on filament

Advantage and Application

Advantages: 

💢Higher operating temp. &hence better Luminous efficacy (22- 33 Lu/W) 

💢 Longer life (2000 working hours) 

💢Reduced blackening of lamp 

💢Reduced dimension 

💢 Better colour rendering 

Application:

💥Outdoor Illumination of building, playground, gardens, airport runways etc. 

💥Indoor illumination of public halls, factories, sports halls, TV studio etc.

Gaseous Discharge Lamps 

👉 Sodium Vapour ↠ (a) High Pressure (HPSV or SON) (b) Low Pressure (LPSV or SOX)

👉Mercury Vapour

👉Neon

👉 Metal Halide 

👉 Fluorescent 

👉Compact Fluorescent Lamp (CFL)

Sodium Vapour Lamp

A sodium vapour lamp is a particular kind of high-intensity discharge (HID) lamp that emits illumination using sodium vapour.

The lamp works by passing an electric current through a tube containing sodium and other gases, which causes the sodium atoms to become excited and emit yellow light.

Contents:

 Construction of High Pressure Sodium Vapour Lamp
 Working Process of High Pressure Sodium Vapour Lamp 

 Electrical & Optical Characteristics High Pressure Sodium Vapour Lamp

 Application of High Pressure Sodium Vapour Lamp

 Construction of Low Pressure Sodium Vapour Lamp 

 Working Process of Low Pressure Sodium Vapour Lamp 

 Electrical & Optical Characteristics Low Pressure Sodium Vapour Lamp

 Application Application of Low Pressure Pressure Sodium Vapour Lamp

(a) High Pressure (HPSV or SON)

Construction:-

✋Commercially, HPSV is known as SON. 

✋ The creation of HPSV lamps can be used thanks to polycrystalline alumina, 

       a transparent ceramic substance. 6 HPSV lamp uses are available.

✋Ceramic (PCA) inner tube,

✋Quartz glass (Fused Silica) exterior jacket, and 

✋Sodium vapour pressure of 7000 Pa and inert gas (Xenon) pressure of 3000 Pa

Building Method

⋙ Atoms are much closer. 

⋙ On increased pressure – Spectrum Broadening due to self absorption of D lines. 

⋙ Much more levels of excitation and hence wider spectrum 

⋙ Yellowish - White Colour Output 

⋙ Leak transformer is used for high starting voltage and reduced working voltage. It 7 voltage and              reduced working voltage. It is step up transformer with high leakage reactance. 

⋙ Electronic Igniter may also be used as control gear. 

⋙ Starting Voltage – 1500-5000V , typically 2500 V for 1micro second 

⋙ Operating Temperature- 4000 K at centre of Plasma Column and 1500 K at wall. Hence. Bulb                Temp– nearly 1200 ° C

⋙ Power rating – up to 1000 W available.

Applications and Visual Properties

⋟ More continuous Spectrum than LPSV 

⋟ Yellow White Light Output 

⋟ Takes time for full brilliance and actual colour output 

⋟ CRI 20 -40 

⋟ CCT – nearly 2000 K Luminous efficacy – 60 -140 Lm /W 8 

⋟  Luminous efficacy – 60 -140 Lm /W 

⋟  Life- 12000 to 24000 working hours 

⋟  It is suitable for Outdoor Lighting – Where, efficacy is essential and colour rendering is not so               important 

⋟ Widely used in Highway, Streetlight, Parks, Rail yards etc.

(b) Low Pressure (LPSV or SOX)

Construction

⇛ LPSV is commercially known as SOX.

⇛ Generally Horizontal Configuration 

⇛ Bulb contains 2 sets of electrode normally made of tungsten in an U shaped arc tube placed within a       borosilicate glass envelope. 

⇛  Arc (discharge) tube contains metallic 3 

⇛ Arc (discharge) tube contains metallic sodium (solid when not working), neon or argon gas as                 Auxiliary gas (Penning Mixture) 

⇛ Sodium Vapour pressure – 1 Pa and inert gas pressure - nearly 1070 Pa (1 Atm pressure = 101325          Pa) 

⇛ The heat-reflective coating of indium oxide allows visible light to pass but reflects infra-red                   radiation back inside the tube

Working Process

🧿AC supply 

🧿Na should never get in contact with air to avoid explosion. 

🧿First discharge through Inert Gas (Neon/Argon, but mainly Neon) gasproducing reddish orange              radiation 

🧿Developed heat vaporises Na & which is finally ionised producing light.

🧿1 st excitation level energy – 2.1 eV. Resonance Radiation for Na is 5893 Å= 589.3 nm. (Yellow). 4        = 589.3 nm. (Yellow). (actually, 589.0 nm & 589.6 nm- D Lines) 

🧿LPSV light output is monochromatic yellow. 

🧿Operating Temp. – 300 ˚ C 

🧿Starting Discharge Voltage 400 – 600 V and Running Voltage – 165 V

🧿Power Rating – 45 -200 Watt.

Optical Characteristics and Application 

ⓄTakes 15 minutes for full brilliance in output.

Ⓞ Life – 10000 - 14000 working hours.

Ⓞ Efficacy – Very high - 140-200 Lm/W (monochromatic radiation near athighest spectral sensitivity      of human eye) 

Ⓞ Power Factor – 0.3 & after improvement improvement 0.8-0.9 

Ⓞ CRI – less than 20 (since monochromatic) even may be negative 

Ⓞ CCT – less than 2000 K 

Ⓞ It is rarely used. Normally used in Tunnel, Store where colour rendering is of low importance.

 

 ⋡ Mercury Vapour                                                      ⋡ Incandescent Lamp 

 

  ⋡  Fluorescent Lamp                                                   ⋡ Metal Halide Lamp   

   

                                                           

Incandescent Lamp

Incandescent Lamp

A lamp is a device that produces light by using electricity to heat a filament or gas inside a glass or quartz bulb. Different sized and shaped lamps can be used for a broad range of tasks, such as general room illumination or accentuating a particular spot or object.

Lamp's are Mainly three type 

 1⇒ Incandescent 

i) Regular Filament

ii) Gas Filled

iii) Halogen

2⇒ Gaseous Discharge

👉 Sodium Vapour ↠ (a) High Pressure (HPSV or SON) (b) Low Pressure (LPSV or SOX)

👉Mercury Vapour

👉Neon

👉 Metal Halide 

👉 Fluorescent 

👉Compact Fluorescent Lamp (CFL)

3⇒.LED

Incandescent Lamp

Regular Filament: 

⇛  At high temperatures, both heat and light are generated.

⇛  The amount of light emission will increase with temperature.

 ⇛  Regular candles and fire are other instances of incandescent lamps.

⇛  Heat and, at higher temperatures, a little light are produced when an electric current is run       through a metallic cable.

⇛  Radiant Efficiency is the proportion of light output to total radiant energy.

⇛ Thomas Alva Edison, inventor of the first electric lamp .

⇛ The carbon filament was used in the first light.

⇛ Porcelain globe that has been fully emptied .

⇛ Filament, which is the fine filament inside the glass globe; 

⇛  Cement, which is the powder-filled cap.

Why was we evacuated?

Primarily to avoid the fine filament wire oxidising at high temperatures, which would cause metal oxide vapour to settle on the interior of the bulb and result in bulb blackening. Lamp life is also decreased.

Filament Material

Required Properties : 

(a) strong resistivity is . i.e. ρ

 (b) a high freezing point 

 (c) a low temperature coefficient of resistance, 

 (d) ductility, 

(e) enough mechanical power .

Tungsten is the most commonly used material for Filament

Why not Carbon ? 

Low m.p.  and  a -ve temperature coefficient of R that causes a significant current inrush

Why Tungsten ?

(a) High m.p. (3400 °C); 

(b) High m.p.

(c) low temperature R's coeff. (0.0051), 

(d) Vapour pressure is minimal 

(e) flexibility 

(f) strong mechanical resistance

Gas Filled Lamp

💥 In a standard filament (vacuum) lamp, the highest working temperature inside the bulb is 2000° C;        above this point, tungsten vapourizes quickly, blackening the lamp and shortening its life.

💥  More pressure and inert gas with a higher molecular weight should be used to combat this.

💥  A  mixture of argon and nitrogen (93:7).

💥  A temperature of 2300° C. and a radiation efficiency of  nearly 10%

💥 Nitrogen's function is to lessen the likelihood of arcing. 

💥  Krypton is the finest alternative, but it is impractical due to its higher cost.

Coiled Coil Structure of Filament

1. The presence of gas results in greater convection heat loss, which further lowers temperature         and radiant efficiency.

 2. A specially designed designed coiled coil filament can reduce convection heat loss.

 3. This design increases effective surface area.

Constructional Features

Constructional Features

Lamp Life and Lumen Depreciation 

✊ The cross sectional area of the filament diminishes due to the slow but constant evaporation of                 tungsten, increasing resistance.

✊ As a result, current current drops, along with Lumen output and efficiency. 

✊  Filament wire is also torn out as a result of ageing effect.

✊ Lamp intake is α V^1.55 and Lamp output is α V^3.55; as a result, Lamp Efficacy is α V^2.

✊ α V^-13 (Vacuum) or α V^-14 lamp life (gas filled)

✊  A compromise between lamp life and lumen power

Advantage and Disadvantage

Advantage:

Direct operation on standard distribution voltage (230V DC/1 φ, 50 Hz, AC) 

 Availability in different size and shape 

 Operating p.f. is unity (i.e. almost purely resistive load)

 No effect of surrounding air temperature

 Easy manufacturing technology

 Low cost 

 Good CRI ( 95 -100) 

 Restriking capability

 Dimming is possible

Disadvantage:

 Poor luminous efficacy (10-15 Lu/w) 

 Short life (500 – 1000 working hour)

Application

💢Was known as a GLS (General Lighting Service) lamp and was used for general lighting for a long          time. 

💢 Now CFL or LED have taken its position. 

💢Where colour reproduction is still crucial, it is utilised 

💢 Studios, photography, the textile or paint industries, a display of clothing or jewellery, or for                  decorative reasons, etc.