ELECTRIC TRACTION – PART – 01 - BRIEF HISTORY OF INDIAN RAILWAYS, IMPORTANT TERMS AND MECHANISM OF TRAIN MOVEMENT

BRIEF HISTORY OF INDIAN RAILWAYS

There were Indian merchants, both in Calcutta and Bombay who took an interest in founding of the railways.

The most prominent of these was a remarkable Bengali merchant Prince DWARKANATH TAGORE, GRANDFATHER OF NOBEL LAUREATE POET RABINDRANATH TAGORE.

Dwarkanath's firm Carr, Tagore & Company, is reported to have offered in 1844, to raise one-third of the capital required for a railway from Calcutta northwest to the coalfields above Burdwan.

The Railway Age dawned in India on 16th. April 1853, when the first train ran from Bombay to Thana, a distance of 21 miles (33.81 Km.)

The first proposals for construction of railways in India were presented in 1844 to East India Company in London by two companies

(i) East Indian Railway Company headed by R.McDonald Stephenson, and

(ii) Great Indian Peninsula Railway Company.

Both East Indian Railway Company and Great Indian Peninsula Railway Company were incorporated in England for the purpose of constructing railway lines in Calcutta and Bombay presidencies respectively.

Though Great Indian Peninsula Railway Company was formed in 1844.

George Stephenson could not see his Locomotives run on Indian soil as he died in 1848.   

Stephenson was a pioneering railway engineer and inventor of the 'Rocket', the most famous early railway locomotive.

INVENTOR OF LOCOMOTIVE - GEORGE STEPHENSON

George Stephenson was born on 9 June 1781 in England. His father was an engine-man at a coalmine.

Stephenson himself worked at the mine and learned to read and write in his spare time.

In 1814, Stephenson constructed his first locomotive, 'Blucher', for hauling coal at Killingworth Colliery near Newcastle.
In 1815, he invented a safety lamp for use in coalmines, nicknamed the 'Geordie'.

In 1821, Stephenson was appointed engineer for the construction of the Stockton and Darlington railway.

It opened in 1825 and was the first public railway.

In October 1829, the railway's owners staged a competition at Rain hill to find the best kind of locomotive to pull heavy loads over long distances.

Thousands came to watch. Stephenson's locomotive 'Rocket' was the winner, achieving a record speed of 36 miles per hour.

Stephenson became engineer on a number of these projects and was also consulted on the development of railways in Belgium and Spain.

Stephenson died on 12 August 1848 in Chesterfield in Derbyshire.

His only son Robert was also a railway engineer and worked with his father on many of his projects.

TRACTION

The adhesive friction between a wheel and a surface, as between a driving wheel of a motor vehicle and the road

TRACTION IN MEDICAL SCIENCE

A way of treating broken bones in which a device gently pulls the bones back into place.

ELECTRIC TRACTION

It means locomotion (the power or ability to move) in which the driving or tractive force is obtained from electric motors.

ADHESIVE

A substance that unites or bonds surfaces together.

FRICTION

A force that resists the relative motion or tendency to such motion of two bodies or substances in contact.

ADHESIVE FRICTION

The friction between a body and the surface on which it moves (as between an automobile tire and the road)

FORCE

A force is a push or pull acting upon an object as a result of its interaction with another object. There are different types of forces.

A force is a vector quantity.

TRACTIVE FORCE

Tractive force is the force used to generate motion between a body and a tangential surface, through the use of DRY FRICTION, though the use of SHEAR FORCE of the surface is also commonly used.

DRY FRICTION

Dry friction resists relative lateral motion of two solid surfaces in contact. Dry friction is subdivided into static friction ("stiction") between non-moving surfaces, and kinetic friction between moving surfaces.

SHEARING FORCES

Shearing forces are unaligned forces pushing one part of a body in one direction, and another part of the body in the opposite direction. When the forces are aligned into each other, they are called compression forces.

ELECTRIC LAMPS – PART – 01 – OPERATION OF INCANDESCENT AND GAS-FILLED LIGHT LAMP

INVENTOR OF INCANDESCENT LIGHT BULB

JOSEPH WILSON SWAN, British Physicist actually received the first patent for a complete incandescent light bulb with a carbon filament in 1878.  

SWAN’S HOUSE WAS THE FIRST IN THE WORLD TO BE LIT BY A LIGHT BULB.

EDISON AND SWAN merged their companies and together they were the first to design a bulb that was commercially viable in 1880.

SWAN'S original low-voltage, high-current bulb is still used in flashlights and automobiles.

INCANDESCENT - Emitting light as a result of being heated

INCANDESCENT LIGHT BULB is a source of light that works by incandescence, which is the emission of light caused by heating the filament.  

OPERATION

An incandescent bulb typically consists of a glass enclosure containing a tungsten filament. An electric current passes through the filament, heating it to a temperature that produces light.

MAJOR PARTS

1. Glass bulb                              2.Inert gas

3. Tungsten filament                  4. Contact wire (goes to foot)

5. Contact wire (goes to base)    6. Support wires

7. Glass mount/support              8. Base contact wire

9. Screw threads                        10. Insulation

11. Electrical foot contact

TYPES

1. CARBON FILAMENT LAMP

Melting point = 3500 degree centigrade

Working temperature = 1800 degree centigrade

Temperature coefficient = negative

Lamp efficacy = 2.5 to 4 lumen per watt

It gives yellowish light

At high temperature, it disintegrates and blackens the lamps inside surface.

2. TUNGESTEN FILAMENT LAMP

Melting point = 3400 degree centigrade

Working temperature = more than 2000 degree centigrade

Temperature coefficient = positive

Lamp efficacy = 14 lumen per watt.

It gives bluish-white light

TYPES OF FILAMENT LAMPS

(A) VACUUM TYPE LAMP

1. This type of lamps are perfectly evacuated. (Evacuate means create a vacuum in (a bulb, flask, reaction vessel).

2. Evacuation prevents oxidation of the filament material.

3. Evacuation results in vaporization of the filament material, which reduces its life.

4. Filament is wound in the shape of net.

5. Length of the filament of lamp is short.

6. Vacuum lamps are made of 10 to 25 watts.

7. At higher temperature the metal will start to disintegrate and the lamp will become defective.

8. This lamp produces less illumination.

(B) GAS-FILLED LAMPS

1. In order to raise the working temperature of a filament the bulbs are filled with an inert gas.

2. This lamps are used at higher wattage more than 100W.

3. A mixture of 80% argon and 20% nitrogen is an ideal combination.

4. Nitrogen reduces arcing between the filament turns.

5. Loss of heat by convection through gas is reduced by decreasing the surface area of the filament.

COILED COIL - FILAMENT

To make a 100W lamp about 300m of tungsten wire is needed.

Such a long wire cannot be accommodated in the small space of a lamp.

First the coil is coiled and is again recoiled; such a filament is called coiled coil filament.

CHARACTERISTICS OF INCANDESCENT LAMP AND DIMENSION OF THE FILAMENT - Please watch the video.

ADVANTAGES

1. Available in various shapes and sizes.

2. Not affected by surrounding temperature.

3. It operates at unity power factor.

4. Works well on either alternating or direct current.

5. They are also compatible with control devices such as dimmers, timers, photo sensors, and can be used both indoors and outdoors.

DISADVANTAGES

1. Low efficiency               

2. These lamps are very much sensitive to voltage changes.

3. The light output is white at higher voltages but the life of the filament reduces.

ILLUMINATION ENGINEERING - PART – 15 – ROAD AND STREET LIGHTING AND THREE PROBLEMS

ROAD 
A general term denoting any public way for purposes of vehicular traffic.

TYPES OF ROAD

1. Ring road – A road an urban area enabling traffic to avoid going to urban centre.

2. Radial road – A road providing direct communication between the centre of an urban area and outer districts. 

3. Collector Road – A link between the radial or ring roads and the local distribution access streets.

4. Trunk Road – A main route in the through communication system of a country.

5. Express Road – A road has no stopping and parking areas.

6. All-purpose Road – Road usable by all traffic including pedestrians and cyclists. Used for to distinguish other roads from motor ways.

STREET, ALLEY, AVENUE AND BOULEVARD ALL REFER TO PUBLIC WAYS OR ROADS IN MUNICIPAL AREAS.

STREET is a round which has become partly or wholly defined by buildings along one or both. 

[OR]  

A STREET is a road in a village, town, or city, especially a road lined with buildings. 

ALLEY is a narrow street or foot way, especially at the rear of or between rows of buildings or lots. 

AVENUE is properly a prominent street, often one bordered by fine residences and impressive buildings, or with a row of trees on each side. 

A BOULEVARD is a beautiful, broad street, lined with rows of stately trees, especially used as a promenade (a public area set aside as a pedestrian walk). 

TYPE OF STREETS  

RESIDENTIAL STREET 

Street with the majority of frontages comprising private houses.

SHOPPING STREET 

Street with frontage comprising a high proportion of shops or other premises which may be lit at night and with heavy pedestrian.

COMMERCIAL STREET 

Street with frontage comprising a high proportion of commercial high proportion of commercial premises usually unlit at night and with a high proportion of heavy goods vehicles in the traffic stream.

WAY - A line leading to a place or point

TYPES OF WAY

1. HIGH WAY – A way for the passage of vehicular traffic over which such traffic way may lawfully pass.

2. CARRIAGE WAY – That portion of high way intended primarily for vehicular traffic.

3. DUAL CARRIAGE WAY – A layout of the separated carriage ways, each reserved for traffic in one direction only.

4. FOOT WAY – The portion of a road reserved exclusively for pedestrians.

STREET LIGHTING 

Street lighting is intended to create an environment at nighttime in which people can see comfortably and can quickly and accurately identify objects on traveled roadways.  Street lighting can improve, safeguard, facilitate, and encourage vehicular and pedestrian traffic.

OBJECTIVES OF STREET LIGHTING

1. Good outdoor lighting can create and encourage a pedestrian friendly environment, which is especially beneficial to neighborhood business districts. 

2. Pedestrian lighting improves walkway illumination for pedestrian traffic and enhances community safety and business exposure. 

3. Lighting for pedestrians is especially important along Main Streets, Mixed Use Streets and Local Connectors, and in other locations where the land use supports large volumes of pedestrians and vehicles.

AVERAGE RECOMMENDED ILLUMINANCE

Outdoor average sunlight ranges from 32 000 to 100 000 lux

Warehouse aisles (a long narrow passage) are lit to approximately 100-200 lux

A bright office requires about 400 lux of illumination

At sunset and sunrise (with a clear sky), ambient outdoor light is also about 400 lux

Building corridors can be lit adequately at around 100 lux

Moonlight represents about 1 lux.

LAMPS USED IN STREET LIGHTING 

1. INCANDESCENT BULB 

A 100 W Incandescent bulb – for general task lighting applications: 1700 lumens output

and its efficacy is 17 lumens/watt

2. FLUORESCENT LAMP 

A 40 W Fluorescent tube – for highly suitable for downtown areas and parking lots and office ceiling lighting - 1600 lumens output and its and its lamp efficacy is 50 lumens/watt

3. HIGH PRESSURE SODIUM LAMP

A 150 W High pressure sodium bulb – for street/area lighting - 12000 lumens output and its efficacy is 80 lumens/watt

4. HALIDE LAMP 

A 400 W Metal Halide lamp - for high bay warehouse lighting: 38000 lumens output and its efficacy is 95 lumens/watt

THE LIGHT OUTPUT RATIO OF A LIGHT FITTING 

This term is defined as the ratio of the total amount of light output of a light fitting (containing a lamp) to that of just the bare lamp. 

When the lamp is placed in a fitting losses of light will occur – this is because with most artificial light sources on the market light is radiated in all directions. 

LUMEN DEPRECIATION OF THE LIGHT SOURCE

Lumen depreciation is a process of the gradual decline in light output that is observed from most light sources over time due to gradual filament or electrode deterioration and blackening of the lamp.

PROBLEMS - 01 

Calculate the spacing distance between two poles having the following details. 

Pole height = 26 feet, width of the road = 2 feet, wattage of each luminaire = 250 W, required lumen = 10 lux, coefficient of utilization = 0.8, lamp, Lamp lumen Depreciation Factor (LLDF)  = 0.9,  and depreciation factor i = 0.8. 

Space to height ratio should be less than three.

PROBLEMS - 02

Calculate the streetlight watt of each luminaire of street light pole having details.

40 W Fluorescent lamp luminous efficacy = 50 lm per watt, Width of the road is 12 feet, distance between each pole = 36 feet, required illumination levels for street light = 6.46 lux per square metre, maintenance factor = 0.29.

Space to height ratio should be less than three.

PROBLEM - 03 

Calculate the power required of a street light for the following streetlight area (fluorescent lighting).

Required illumination level for street light = 6.46 lux per square metre, luminous efficacy of fluorescent light = 50 lumen per watt and required streetlight area to be illuminated = 1 square metre.

ILLUMINATION ENGINEERING - PART – 14 – DIFFERENCE BETWEEN ILLLUMINANCE AND LUMINANCE – THREE PROBLEMS IN FLOODLIGHTING DESIGN

DIFFERENCE BETWEEN ILLUMINANCE AND LUMINANCE

ILLUMINANCE OR ILLUMINATION (E) is the measure of light falling on a surface (lumens per square metre or lux)

E is measured by the units fc (lx) ; fc being the symbol for foot candles and (lx) the symbol for lux in the International System (SI).

LUMINANCE OR BRIGHTNESS (B) is measured by the units fL(cd/sq.metre); fL being the symbol for foot Lamberts and (cd/m2) the symbol for candela per square meter.

Luminance refers to light reflected from it or emitted by it (candela per square metre or alternatively a possible illuminance x reflection factor).

LUMINAIRE is the name given to a complete light source and the light fixture.

REFLECTION FACTOR

In case of diffused reflecting surface the brightness or luminance gets reduced by an amount known as reflection factor.

Reflection Factor (R.F) is the ratio of reflected luminous flux to total incidental luminous flux.

Brightness (B) = [Reflection factor x Illumination (E)]/ ∏ in cd/sq.metre.

Reflection factor = [∏ x B] / E

PROBLEM – 01

A building measuring 40 m x 25 m is to be floodlit on the front side with brightness of 25 lumens per sq. metre. Coefficient of reflection of building surface is 0.25. Lamps of 500 W having lumens output of 8000 each are used. Assuming beam factor as 0.6, waste light factor 1.2 and maintenance factor as 0.75, determine the number of lamps required.

PROBLEM – 02

It is desired to flood-light the front of the building 40 m wide and 15 m high. Projector of 1000-W lamps giving 20 lumen/watt are available. If the desired level of illumination is 75 lm/sq. metre and if the projectors are to be located at ground level 12 m away, design and show a suitable scheme.

Assume the following – Coefficient of utilization is 0.4, depreciation factor is 1.3 and waste light factor is 1.2.

PROBLEM – 03

Estimate the number of 1000-W floodlight projectors required to illuminate the upper 75 m of one face of the 95 m tower of width 15 m if approximate initial average luminance is to be 6.85 cd/sq.metre. The projectors are mounted at ground level 50 m away from base of the tower. Utilization factor is 0.2, reflection factor of wall is 25% and efficacy of 1000-W lamp is 18 lm/watt.

ILLUMINATION ENGINEERING – PART – 13 – THUMB RULES OF FACADE, SIGN, FLAG, GERNEAL AREA AND MONUMENT LIGHTING

 TYPES OF FLOOD LIGHTING APPLICATIONS

1. Facade (the face or front of a building) lighting  

2. Sign (a public display of a message) lighting

3. Flag lighting 

4. General area lighting and 

5. Monument lighting

FACADE LIGHTING - When lighting building facades with ground-mounted floodlights, three factors are to be considered.

1. Setback distance – Distance between the building and the floodlight projector.

The recommended setback is 3/4 times the building height. 

If a building is 40 feet tall, the recommended setback is 30 feet from the building.  Locating the floodlight closer to the building will sacrifice uniformity; setting it farther back will result in loss of efficiency.

2. Spacing – Distance between floodlight projectors

The rule of thumb for spacing floodlights is not to exceed two times the setback distance. 

If the setback is 30 feet, the floodlights should not be placed more than 60 feet apart.

3. Aiming distance – Distance aimed for flood lighting the front side of the building

The floodlight should be aimed at least 2/3 the height of the building. 

For example, if a building is 40 feet high, the recommended aiming point is approximately 27 feet high. 

After installation is complete, aiming can be adjusted to produce the best appearance.  Mounting a full or upper visor to the floodlight can reduce unwanted spill light.

SIGN LIGHTING - When lighting a sign with ground-mounted floodlights, three factors to be considered.

1. Setback distance - Distance between the building and the floodlight projector.

When using ground-mounted floodlights to light a sign, the recommended setback is a distance equal to 3/4 the sign height. 

For example, the setback distance for a 16 foot by 8 foot sign would be 6 feet.  

Locating the floodlight closer will sacrifice uniformity while setting it farther back will result in a loss of efficiency. 

2. Spacing - Distance between floodlight projectors

The rule of thumb for spacing floodlights is not to exceed two times the setback distance. 

If the setback is 6 feet, the floodlights should not be placed more than 12 feet apart.

3. Aiming distance - Distance aimed for flood lighting the front side of the building

The floodlight should be aimed at least 2/3 up the sign. 

For example, if a sign is six feet tall, then the floodlight will be aimed at approximately four feet high. 

After installation is complete, aiming can be adjusted to produce the best appearance.  Mounting a full or upper visor to the floodlight can reduce the unwanted glare.

FLAG LIGHTING - Ground-mounted floodlights are often used to provide illumination for flags. 
The most important factors to be considered are: Wattage, Distribution, Setback, Spacing, Aiming, Fixtures.

Depending on pole height, flag size, and ambient light levels, the wattage of lamp used in the lighting fixture should be carefully considered when choosing the appropriate fixture for your flag lighting application.

1. Setback distance - Distance between the building and the floodlight projector

The recommended setback for lighting a flag is 1/3 times the pole height. 

If the pole is 40' tall, the floodlight should be set back a distance of 13.33' away from the pole.

GENERAL AREA LIGHTING - Pole mounted floodlights are commonly used for general area lighting applications such as parking lots and storage yards.

The factors to be considered are mounting height, spacing distance, vertical aiming and horizontal aiming.

1. Mounting Height - It is the height of the lamp to be fixed at the top of the pole

The recommended mounting height is one half the distance across the area to be lighted.  If the area to be lighted is 40 feet across, the lowest recommended mounting height is 20 feet.

Mounting height = 1/2 distance to be lighted [1/2 (40 ft.) = 20 ft.]

2. Spacing distance - Distance between the two poles

When more than one pole is added, pole placement is a concern.  

The "4 times" rule of thumb for spacing indicates that a pole should be placed four times the mounting height from the adjacent poles.  

If a floodlight is mounted on a 20 foot pole, space the poles 80 feet apart.

Pole Spacing = 4 x mounting height [4 (20 ft. pole) = 80 feet between poles]

3. Vertical Aiming

A single floodlight uses the two-thirds rule of thumb for vertical aiming.  

The fixture is aimed 2/3 of the distance across the area to be lighted and at least 30 degrees below horizontal.  

If the area to be lighted is 40 feet across, the recommended aiming point is 27 feet.

Aiming point = 2/3 across distance to be lighted [2/3 (40 ft.) = 27 ft. aiming point]

Additionally, to minimize glare, the recommended aiming point distance should never exceed twice the mounting height.  

If a pole is 20 feet high, the vertical aiming point should not exceed 40 feet out. 

4. Horizontal Aiming

When an additional floodlight is added to a single pole, horizontal aiming also must be considered.  

First, each floodlight should be vertically aimed according to the two-thirds rule above. 

MONUMENT (LIGHTING (An important site that is marked and preserved as public property)

1. Most prominent feature

Select the single most prominent characteristic of the statue or monument, possibly a face or emblem, and illuminate it with a single spot. 

More than one spot may be needed to provide visual interest from all viewing locations.

2. Texture (the essential quality of something) & Three-dimensional quality

Develop a grazing effect by placing fixtures at the base of the statue, aimed straight up.  Strong shadows will highlight the texture and three-dimensional quality of the work.  

This effect may be produced with either spot or horizontal spot distributions. 

3. Profile, Silhouette (a drawing of the outline of an object; filled in with some uniform color)

* Should the statue be located in front of a wall or similar surface such as a row of trees, consider lighting this background surface so that the dark statue is seen in silhouette against the light background.  

* This technique is particularly effective in accenting the overall shape, such as a rider on horseback.  

* Provide sufficient background illuminance or brightness so that a strong accent effect exists between the background and statue.

ILLUMINATION ENGINEERING - PART – 12 - FLOOD LIGHTING - IMPORTANT TERMS AND TWO PROBLEMS

FLOOD LIGHTING 
An artificial light so directed or diffused as to give a comparatively uniform illumination over a rather large given area.
Floodlights are broad-beamed, high-intensity artificial lights.
They are often used to illuminate outdoor playing fields while an outdoor sports event is being held during low-light conditions.
More focused kinds are often used as a stage lighting instrument in live performances such as concerts and plays.
Flood lighting is the use of high-powered light bulbs to illuminate a large, outdoor space.
It is very common to use flood lighting to accentuate the architectural features of a historical or impressive building.
The use of flood lights enhances the details of the building.
The dimensions of the building determine the physical size of the lighting unit.
To illuminate a very tall building, the lighting unit must be large enough to project the level of light required.
In general, the unit should be placed at least 75% of the building height away from the base of the building.
Sign lighting often requires more than one flood light.
These units should be installed equidistant from each other and centered on the sign. A standard rule of thumb is that the lights should be less than half the distance from the base of the sign apart from each other.
General area lighting is used for security and sporting events.
These lights are usually installed on the top of very tall poles to illuminate a large area.

IMPORTANT TERMS IN FLOOD LIGHTING

BEAM LUMENS
The luminous flux contained within the beam as defined in beam angle.
It is usually taken as 25 to 30 percent of the lamp lumens.
No. of flood light required = Average illumination x Area / Beam angle

BEAM ANGLE 
The angle within which the diversity of illumination produced on a surface or right angles to the beam does not exceed 10 to 1.
For symmetric flood lights there will be two beam angles, one in elevation and another in azimuth (The azimuth of a celestial body is the angle between the vertical plane containing it and the plane of the meridian).

BEAM FACTOR (OR) COEFFICIENT OF UTILIZATION
It is defined as the ratio of beam lumens to the lamp lumens.
Its value is 0.3 and 0.5.

DEPRECIATION FACTOR 
Due to dirt and dust on projector surface, the effectiveness of the projector produce from 50% to 100% and hence more light should be provided than is theoretically required so that illumination should be adequate.

WASTE LIGHT FACTOR
When several flood lights are illuminating a surface, there is bound to be some amount of overlap and also some of the light will fall beyond the edge of the area to be illuminated.
Waster light factor has a value of 1.2 for rectangular areas and 1.5 for irregular areas such as monuments or statues.

FLOOD LIGHTING CALCULATIONS

STEP ONE – The illumination level lux required - Depends upon the type of building, the purpose of the flood lighting.

STEP TWO – Selection of type of projector.
CLASSIFICATION OF PROJECTORS
1. Narrow beam projectors with beam spread between 12 and 25 degree
[Used for distance beyond 70 metres]
2. Medium angle Projectors with beam spread between 25 and 40 degree.
[Used for distance between 30 – 70 metres]
3. Wide angle Projectors with beam spread between 40 and 90 degree.
[Used for below 30 metres]

STEP THREE – The number projectors required is obtained from the following relation.
N = (Area of surface to be illuminated  x Illumination x depreciation factor x waste light factor)/( Beam factor x wattage of lamp x luminous efficacy of lamp)

PROBLEM – 01 – The front of a building 50m x 25m is to be illuminated by twenty five thousand 1000W lamps are arranged so that uniform illumination is obtained. Determine the illumination on the surface.
Assume - waste light factor = 1.2, Depreciation factor = 1.3, Utilization factor = 0.4 and luminous efficacy of 1000W lamp = 18 lumen per watt.

PROBLEM – 02 – The front of a building 100m x 15m is to be illuminated 100 lumens per square metre on the surface by flood light projectors of 1000W lamps arranged to get a uniform illumination. Determine the number of projectors required.
Assume - waste light factor = 1.2, Depreciation factor = 1.3, Utilization factor = 0.2 and luminous efficacy of 1000W lamp = 18 lumen per watt.