Selection for Street Light Luminar-(PART-4)


Type of Ballasts

  • Discharge lamps (fluorescent, HID) and solid state lamps cannot be connected directly to the mains for its functioning. It required control gear for starting the Lamp.
  • This gear has mainly two functions ignition of the lamp and control of the functioning by supplying the right lamp voltage and limiting the electric current.
  • Control gear conventionally consists of three parts (1) Ballast (coil), (2) Capacitor and (3) Igniter.
  • Commonly the control gear is called ballast.
  • Ballast is classified under following categories. (1) Electromagnetic and (2) electronic.
  • Electronics Ballast: Electromagnetic ballast has electromagnetic ballast, an igniter (not for HPM-lamps) and a capacitor.
  • The ballast lifetime depends on service hours. Normally, magnetic ballasts last as long as the luminaries if they are placed inside the luminaries (and thus are protected against rain).
  • The lifetime of igniters associated with magnetic ballasts does not depend on hours in service but on the number of times that the lamps are switched on.
  • Electronics Ballast: An electronic ballast is mostly one unit that provides both ignition and good functioning (by supplying the right lamp voltage and limiting the electric current) of the lamp.
  • For electronic ballasts, lifetimes of 40.000 to 60.000 hours (10 to 15 years) are considered.
  • The lifetime of electronic ballasts decreases strongly if the working temperature in reality exceeds the indicated working temperature.
  • Electronic ballast includes an ignition device and does not have a separate igniter.

 Power Consumption in Ballasts:

  •  Electronics Ballast: Normally the Fluorescent lights are using electronic ballast (called solid state ballast) which consume above 12 watts power.
  • Magnetic Ballast: the stating modes are available in Programmed stat, instant stat, and rapid start Lamp flicker index is 0.04 to 0.07, Dimming is not available for this ballast.
  • Hybrid Ballast: the stating mode is rapid stat, Lamp flicker index is 0.04-0.07. Dimming is not available for this ballast.
  • Instant start Ballast: supply a high initial voltage (over 400V) to start the lamp. High voltage is required to initiate the Discharge between unheated electrodes.  
  • Rapid Start Ballast: supply 200-300V to start the lamp, which can heating the electrodes to approximately 1470˚F(800˚C).
  • It starts the lamp with brief delay but without flashing. And for the Fluorescent lamp, warm up time is also minimum 5 minutes.

 Replacement of Laminar:

  •  HSPV produce a yellowish light, have a long life, are very energy-efficient, and have good lumen maintenance (maintain light output for a long period of time), but have poor color rendering properties.
  • MH lamps are the most frequently used alternative to HPSV in new installations. They are also quite efficient and provide much better color rendering. However, these lamps tend to have a shorter lamp life (< 10000 hours) and poor lumen maintenance over the life of the lamp.
  • Mercury lamp replaced to incandescent lamp:
  • This is popular conversion of laminar. The initial cost of MV Lamp is high and it requires ballast, but MV Lamp have high efficacy and long life make it considerably more attractive than the incandescent lamp.
  • The blue-white color of the clear lamp is generally acceptable, and the arc tube size provides a light source that is small enough to permit good light control.
  • A phosphor-coated outer bulb, featuring both higher output and more pleasing color rendition, is also available. However, the light source is the size of the outer bulb, presenting a problem in light control.
  • The metal halide lamp is a type of mercury lamp in which the arc tube contains, in addition to mercury, certain metal halides which improve both the efficacy and the color rendition without the use of a phosphor-coated bulb. The light source size is that of the arc tube, permitting good light control in the same fixture used for clear mercury lamps.
  • MV lamps are the least efficient of the HID types and have poor lumen maintenance
  • High pressure sodium (HPS) lamp replaced tomercury :
  • The high pressure sodium (HPS) lamp is presently replacing the mercury lamp. It has golden-white color light output.
  • HPS lamps are normally operated with special ballasts that provide the necessary high voltage to start the lamp. However, lamps are available that can be operated from certain types of mercury lamp ballasts, but with poorer lumen maintenance and shorter life. There are also HPS lamps available that provide improved color rendition or almost instant restart after a power interruption; either feature results in a reduction in rated life.
  • LED replaced toHigh pressure sodium (HPS) lamp :
  • LED lights use approximately 60% less electricity than HPS lights

Savings by Use of More Efficient Lamps (Bureau of Energy Efficiency)

Existing Lamp Replace by Energy Savings
GLS (Incandescent) Compact Fluorescent Lamp (CFL) 35 to 60 %
High Pressure Mercury Vapor (HPMV) 40 to 50 %
Metal Halide 65 %
High Pressure Sodium Vapor (HPSV) 65 to 75%
Tungsten Halogen High Pressure Mercury Vapor (HPMV) 50 to 60 %
Metal Halide 40 to 70 %
High Pressure Sodium Vapor (HPSV) 40 to 80 %
High Pressure Mercury Vapor(HPMV) Metal Halide 35 %
High Pressure Sodium Vapor (HPSV) 35 to 60 %
Low Pressure Sodium Vapor (HPSV) 60 %
Metal Halide High Pressure Sodium Vapor (HPSV) 30 %
Low Pressure Sodium Vapor (HPSV) 40 %
High Pressure Sodium Vapor(HPSV) Low Pressure Sodium Vapor (HPSV) 40 %

 

 

Variation in Light Output and Power Consumption (BEE, India)

Type of Lamp 10% lower voltage 10% Higher voltage
Light Out Put Power Out Put Light Out Put Power Out Put
Fluorescent lamps Decreased 9% Decreased 15% Increased 9% Increased 15%
HPMV lamps Decreased 20% Decreased 16% Increased 20% Increased 17%
Mercury Blended lamps Decreased 24% Decreased 20% Increased 30% Increased 20%
Metal Halide lamps Decreased 30% Decreased 20% Increased 30% Increased 20%
HPSV lamps Decreased 28% Decreased 20% Increased 30% Increased 26%
LPSV lamps Decreased 4% Decreased 8% Increased 2% Increased 3%

  References:

  • Indian Renewable Energy Development Agency
  • URBAN DESIGN STANDARDS MANUAL
  • USAID-India.
  • HIGHWAY LIGHTING-Illinois

Selection for Street Light Luminar-(PART-3)


Type of Street Light Lamp:

  • Street lighting Lamps normally used three types High intensity discharge (HID) lamps, High pressure sodium vapor (HPSV), Metal halide (MH), or Mercury vapor (MV).
  • However Mainly Lamps for Street lighting can be divided into three main categories (1) incandescent lamps and (2) luminescent gaseous discharge lamps. (3) LED
  • The lamps used in street lighting today are mostly High Intensity Discharge (HID) lamps that include high pressure sodium, low pressure sodium, high pressure mercury and metal halide lamps.
  • In order to reduce the emission of greenhouse gases, the use of energy efficient lamps such as Light Emitting Diodes (LED) for Street lighting has increased. Untitled

 (1) Incandescent (INC):

  • The incandescent or filament lamp was for many years the most commonly used. However, its low efficacy and short rated life have made it undesirable for new installations.
  • Advantage:
  • Inexpensive
  • Available in Different Configurations & Colors
  • No warm up is required
  • Easily controlled
  • Dis Advantage:
  • Inefficient ( 10-25 lumens/watt )
  • Short lamp life
  • Vibration sensitive
  • Over-voltage sensitive

 (a) Fluorescent (FL):

  •  At many places tube lights are used for Street Light lighting.
  • Tube lights in general are available in lower wattages and they cannot produce the same kind of brightness as a Halogen or Sodium Vapour lamp. So they should not be used to replace Halogen lamps, as they cannot produce the same amount of brightness
  • Lamps are available in the following configurations: T5,T8,T10,T12,T17 Untitled
  • Standard Fluorescent Lamps T8 Lamps: 32W and 55W
  • Typically used with electronic ballast
  • Standard Fluorescent Lamps T5 Lamps: 14W, 21W, 24W, and 35W
  • Typically is used with electronic ballast
  • Standard Fluorescent Lamps T12 Lamps: Standard lamp wattages
  • Advantages
  • Efficient(75+ lumens/watt)
  • Available in many configurations
  • Desirable colors available (2,700K to 4,100K)
  • Long life (6,000 –20,000 hours)
  • Disadvantages
  • Require a ballast
  • Temperature sensitive
  • May require special controls

 (b) Tungsten-Halogen Lamps:

  • Halogen lamp is incandescent Type lamp. It has a tungsten filament filled with halogen gas.

Untitled

  • Advantages
  • More compact
  • Longer life
  • More light
  • Whiter light (higher color temp.)
  • Disadvantages
  • Cost more
  • Increased IR
  • Increased UV
  • Light Color: Whit Yellow ,light Blue Color
  • Efficiency: Poor Efficiency (10 to 18 lumen/Watt)
  • Lamp Life: Long Life ( 2400 Hours)
  • Initial Cost: High initial Cost
  • Warm up Time:

Application: For outdoor areas/ parking lot lighting

 (2) High Intensity Discharge (HID) Lamps:

  • HID lamps in general require an external ballast to operate. HID lamps usually take between 1 and 5 minutes to reach full brightness, and if there is a dip in electricity, these lamps will shut off.
  • HID lamps must cool sufficiently to re strike, which usually takes from 1 minute to 10 minutes.
  • There are Mainly Two type of High discharge lamp
  • (1) High Pressure Lamp (HP)
  • (A) Mercury Vapor Lamp(MV)
  • (B) Metal Halide Lamp
  • (C) Sodium Lamp
  • (2) Low Pressure Lamp (LP)
  • (a) Mercury Fluorescent Tube
  • (b) Sodium Lamp
  • Ballasts, which are required by both fluorescent and HID lamps, provide the necessary circuit conditions (voltage, current, and wave form) to start and operate the lamps.
  • HID Lamps Characteristics
  • All HID lamps utilize an internal arc tube and outer envelope construction
  • All HID lamps require ballast for operation.
  • All HID lamps require warm up period
  • All HID lamps require cool-down period before they can re-strike

 (A) High Pressure Mercury Vapor Lamps (HPMV):

  • It is oldest Type of Lamp in HID Type.
  • Prior to the introduction of HPS lamps, MV was the most commonly used light source in highway applications. The MV lamp produces a bluish white light and is not as efficient as the HPS lamp.
  • Lamp sizes: 50,70,100,150,175,200,250,350, 400, and 450W
  • Advantage:
  • Mercury vapor lamps can provide certain low cost options for replacing less efficient lamps such as incandescent lamps without changing the fixtures.
  • Pulse start MH lamps utilize an improved ballast design to improve operation.
  • Higher efficacy
  • Faster warm-up and re-strike longer life
  • Better color uniformity
  • Energy & maintenance savings (15%)
  • Disadvantages:
  • Due to their lower efficacy and poor color rendition they are seldom used in new construction. Color shift toward the end of lamp life
  • Some lamps are designed for enclosed fixtures only
  • Orientation sensitive ( horizontal vs. vertical )
  • Light Color: Bluish white ,Pale Blue-Green Color
  • Efficiency: Lowest Efficiency in HID Type (30 to 65 lumen/Watt)
  • Lamp Life: Long Life ( 2400 Hours)
  • Initial Cost: Low initial Cost
  • Warm up Time: Faster warm-up and re-strike longer life
  • Application: For outdoor areas/ parking lot lighting ,farm light, fish pond

 (B) High Pressure Metal Halide lamps (MPMH):

  • MH lamps produce better color at higher efficiency than MV lamps. However, life expectancy for MH lamps is shorter than for HPS or MV lamps.
  • They also are more sensitive to lamp orientation than other light sources.
  • Metal Halide bulbs are as energy efficient as Sodium Vapour lamps.
  • Metal halide lamps are similar in construction to MV lamps. Some MH lamps can be operated off Mercury Vapor ballasts.
  • MH lamps offer a number of advantaged over MV lamps.

Untitled

  • Light Color: A crisp clear white lights
  • Efficiency: Quit Efficient (80 lumen/Watt)
  • Lamp Life: Less (6000-20000 hrs)
  • Warm up Time:2-3 minutes, hot re-strike 10-20 minutes.
  • Application: It is used where color rendering is critical, such as car lots, service stations, athletic fields, industrial manufacturing.

 (C) High Pressure Sodium Vapor Lamp (HPSV):

  • High pressure sodium lamps are used for both interior and exterior applications and mainly used for street lighting.
  • HPS is higher efficient and better choice than metal halide for street light applications.
  • HPS is the energy efficient options for halogen lamps as they provide double the amount of brightness for the same amount of wattage.
  • HPS lamps differ from mercury and metal-halide lamps because HPS do not contain starting electrodes, the ballast circuit includes a high-voltage electronic starter.
  • The arc tube is made of a ceramic material

Untitled

  • Advantages:
  • If a Halogen is replaced with Sodium Vapour lamp, 20-25% savings can be achieved.
  • Disadvantages:
  • Their brightness is highest in the canter (just below the pole) and is lesser on the outside
  • Light Color: golden-yellowish-White, Orange color light.
  • Advances in electronics now make it possible to dim HPS fixtures in a cost effective manor such as production areas and warehouses.
  • Efficiency: Quit Efficient (80 to 100lumen/Watt)
  • Lamp Life: Long Life (2400 Hours)
  • Warm up Time: 10 minutes, hot re-strike within 60 seconds
  • Operating sodium at higher pressures and temperatures makes it highly reactive
  • Application:Mostly use on Street lighting.
  • plant growing in green houses

Selection for Street Light Luminar-(PART-2)


Classification of Street:

 

Classification Roadway Traffic
Classification Number Number of Vehicles per Hour
Maximum Night Hour Both Direction
Very light traffic Under 150
Light traffic 150 500
Medium traffic 500 1200
Heavy traffic 1200 2400
Very heavy traffic 2400 4000
Heavy traffic Over 4000

 

Classification of Pedestrian Traffic
Light or No Traffic Residential, warehouse areas on express / elevated depressed roadways
Medium Traffic Secondary business streets and some industrial roads
Heavy Traffic Business streets.

 

Mounting Height of Street Light Laminar:

  •  The distance the lamp is mounted above the roadway will affect the illumination intensity, uniformity of brightness, area covered, and relative glare of the unit.
  • Higher mounted units will provide greater coverage, more uniformity, and reduction of glare, but a lower illumination level.
  • It is necessary to weigh the effects of larger lamps against a greater number of smaller units at lower mounting heights with maximum glare potential.
  • The height of luminaries above the roadway surface varies from 5 Meter to more than 20 Meter.
  • Conventional roadway lighting utilized mounting height of 8 to 20 Meter. The lower mounting heights require the use of cutoff or semi-cutoff luminary’s distribution to minimize glare.


Height of Pole Application
6 Meter For streets ,alleys, public gardens and parking lots
8 Meter Urban traffic route, multiplicity of road junctions,
Narrow roads such as local access roads in residential areas in which a mounting height between 10 M or 12 M and 5 M or 6 M is required.
10 Meter Urban traffic route, For wide heavily used routes where a large number of intersection, bends can lead to a short spacing making the use of 12 M mounting height uneconomical.
12 Meter Wide or heavily used routes where advantage can be taken of a longer spacing of luminaries.
18 Meter and above High mast lighting poles shall be installed at large-scale area such as airports, dockyards, large industrial areas, sports areas and road intersections


Type of Road Pole Pole Height Laminar Watt Type of Laminar
Rural Aluminum or Steel Pole 10 to 16 Meter 250W to 400W HPS
Urban Aluminum 10 to 13 Meter 250W to 400W HPS (Cut off or Semi Cut off)

 High Mast Lighting Systems:

  • High mast lighting has 3 or 4 no’s of 1000 watt HPS luminaries mounted on poles /towers, at mounting heights (30 Meter). It develops a highly uniform light distribution.
  • Advantage:
  • Excellent uniformity of illumination, reduce glare with a substantially smaller number of pole locations.
  • Application:
  • Where continuous lighting is desirable such as lighting of toll plazas, rest areas ,parking areas, general area lighting, highways , traffic lanes.
  • High mast lighting is also desirable where there is minimal residential area.
  • High Mast used at remote location to eliminates the need for maintenance, vehicles obstructing traffic on the roadway.
  • High Mast having symmetric or asymmetric distribution
  • The design and installation of high mast lighting equipment is more complex than conventional lighting.

 

Correction Lamp Comparison Chart (Bureau of Energy Efficiency, Delhi)

Lamp Type Lamp ( Watts) Efficacy (Lumens /Watt) ColorRender

 

LampLife (Hr) Remarks
Incandescent (GLF) Lamps:
(Incandescent bulbs) 15,25,40,60,75,100,150,200, 300,500               (no ballast) 8 to 17 100 1000  
Tungsten Halogen  75,100,150,500,1000,2000 (no ballast) 13 to 25 100 2000  
Fluorescent Tube lights(Argon filled) 20,40,65, (32,51,79) 31 to 58 67 to 77 5000  
Fluorescent Tubular Lamp (T5) 18,20,36,40,58,65 100 to 120 Very Good 15,000 to 20,000  Energy-efficient,long lamp life,

only available in low wattages

Compact Fluorescent Lamps (CFLs) 5,7,9,11,18,24,36 26 to 64 85 8000  
HID Lamps:
High Pressure MercuryVapor (HPMV) 80,125,250,400,1000,2000 25 to 60 45 (Fair) 16,000 to 24,000 High energy use,Poor lamp life
High Pressure   Metal Halide Lamps (HPMH) 70,150,250, 400,1000,2000 62 to 72 70 (Excellent) 8000 to 12000 High luminous efficacy, Poor lamp life
High Pressure SodiumVapor Lamps (HPSV) 70,150,250,400,1000 69 to 108 25 to 60 (Fair) 15000 to 24000 Energy-efficient, poor color rendering
Low Pressure Sodium Vapor Lamps (LPSV) 35,55,135 90 to 133 Very Poor 18000 to 24000 Energy-efficient, very poor color rendering
Low Pressure Mercury   Fluorescent TubularLamps (T8 & T12) 35,55,135 30 to 90 Good 5000 to 10000 Poor lamp life, medium energy use, only available in low wattages
LED Lamps
Light Emitting Diode (LED)   70 to 160 Good 40,000 to   90,000 High energy savings, low maintenance, long life, no mercury. High investment cost, nascent technology

Selection for Street Light Luminar-(PART-1)


Terminology for Road Light Illumination:

 (1) Luminance (E):

  • Luminance is the amount of light falling on a surface.
  • The luminance refers to the incidence of the light flux on a surface, per unit of surface.
  • E = Phi / A (lx)
  • The luminance is expressed in lux (lx).
  • Full moon has 0.1 Lux ,Emergency lighting has 1 Lux ,Street lighting has 10 Lux ,Winter day has 10 000 Lux , Summer day has 100 000 Lux

 (2) Lumen (lm):

  • Lumen is a unit of measure of the quantity of light.
  • One lumen is the amount of light which falls on an area of one square foot every point of which is one foot from the source of one candela.
  • A light source of one candela emits a total of 12.57 lumens.

 (3) Lux:

  • Lux is a metric measurement of light on a surface.
  • The illumination of light flux is expressed in Lux hence unit of luminance is Lux.
  • The luminous flux per unit area of 1 square meter on a sphere of radius 1 meter is called 1 Lux.
  • 1 Lux= 1 Lumen per square Meter.
  • Lux = Lumens / Area (sq meter).
  • 1 Lux equals 0.0929 foot candle
  • Difference between Lumens and Lux
  • One Lux is defined as being equivalent to one lumen spread over an area of one square meter.
  • Measurement of lux (light intensity) tells us how many lumens (total light output) we need in the given area of illumination.
  • Lighting a larger area to the same measurement of lux requires a larger number of lumens which is usually achieved by increasing the number of light fixtures.

(4) Foot candle (fc):

  • It is the English unit of Illuminance.
  • It is the amount of light flux density. It is the unit of measure used when describing the amount of light in a room and expressed in lumens per square foot.
  • It is the amount of light that falls on the area we want to illuminate. We also want to know the lumens per square foot or square meter in a space.
  • This quantity called Light Flux Density is the common term Foot-candle (fc).
  • Foot candle = Lumens / Area
  • Example: A 40-watt fluorescent lamp 120 centimeters long produces 3,200 lumens of light in a room having a general dimensions of 10 x 20 ft. Find the illumination on the floor.
  • Foot candle (fc) = Lumens / Area
  • Foot candle (fc) = 3,200 lm / 10×20 ft = 16 foot candle
  • The foot candle is an important unit of measure in calculating the desired illumination and layout of fixtures.

 (5) Foot candle (fc):

  • The unit of luminance = the luminous fl ux per square foot on a sphere of radius 1 foot.
  • One foot-candle is approximately 10 lux.

 (6) Luminance:

  • Luminance indicates the degree of brightness with which the human eye perceives a light source or an illuminated surface.
  • L = E/A (cd/m2)
  • The luminance is expressed in candela per square meter (cd/m2).
  • The amount of light reflected from a surface. It is sort of the “brightness” we see, i.e. the visual effect of the luminance.
  • It depends on the amount of luminance and on the reflective properties of the surface as well as on the projected area on the plane perpendicular to the direction of view.
  • The unit is candela per square meter (cd/m2), or candela per square foot

(7) Lamp Circuit Efficacy:

  • Amount of light (lumens) emitted by a lamp for each watt of power consumed by the lamp circuit, i.e. including control gear losses. This is a more meaningful measure for those lamps that require control gear. It’s Unit is lumens per circuit watt (lm/W)

 (8) Uniformity ratio:

  • G = Emin/Egem (%) The uniformity ratio is the ratio between the minimum luminance and the average luminance on a surface. This figure indicates the degree of “evenness”. E = 1 indicates complete uniformity.

 (9) Utilization Factor (UF):

  • UF (%) The utilization factor indicates how well a lighting installation uses the luminous flux of the lamps. This is indicated as the ratio between the luminous flux that reaches the working plane and the light source of the „bare‟ lamps, expressed as a percentage.
  • The utilization factor of lamps is the ratio of luminous flux which is arrived to the road from the full luminous flux of lamp. It is calculated by using the curse sign of utilization factor which is different from each lamp.

 (10) Coefficient of Utilization (CU):

  • A design factor that represents the percentage of bare lamp lumens that are utilized to light the pavement surface. This factor is based on the luminaries position relative to the lighted area.

 

Coefficient of Utilization

Fixture Description

cu

Efficient fixture, large unit colored room

0.45

Average fixture, medium size room

0.35

Inefficient fixture, small or dark room

0.25

 (11) Lamp Lumen Depreciation Factor (LLD):

  • As the lamp service life increase, the lumen output of the lamp decreases. This is an inherent characteristic of all lamps.
  • The initial lamp lumen value is adjusted by a lumen depreciation factor to compensate for the anticipated lumen reduction. This assures that a minimum level of illumination will be available at the end of the assumed lamp life, even though lamp lumen depreciation has occurred. This information is usually provided by the manufacturer.
  • Mostly used LLD=0.80

 (12) Luminaries Dirt Depreciation Factor (LDD):

  • Dirt on the exterior and interior of the luminaire, and to some extent on the lamp itself, reduces the amount of light reaching the pavement.
  • Various degrees of dirt accumulation may occur depending upon the area in which the luminaire is located. Industrial areas, automobile exhaust, diesel trucks, dust and other environs all affect the dirt accumulation on the luminaire.
  • Higher mounting heights, however, tend to reduce the vehicle-related dirt accumulation.
  • Mostly LDD=0.9

 (13) Maintenance Factor (MF):

  • The maintenance factor is the combination of light loss factors used to denote the reduction of the illumination for a given area after a period of time compared to the initial illumination on the same area. It is the product of the lamp lumen depreciation factor and the luminaire dirt depreciation factor (i.e., MF = LLD x LDD).
  • Consult the manufacturer’s data and the Electrical and Mechanical Unit for the appropriate factors to use.

 

Maintenance Factor

Enclosed fixture, clean room

0.8

Average conditions

0.7

Open Fixture or dirty room

0.6

 (14) Color Rendering Index (CRI):

  • It is ability of a light source to render colors and make them appear “normal.”
  • The index scale runs from 0-100. A CRI of 100 means colors look “normal”, a low CRI means colors look distorted.
  • CRI of 60 means the source renders 60% of the colors well and 40% poorly.
  • Halogen and Incandescent lamps generally have a CRI of 100.

Illumination Unit Comparisons

Term

English

Metric (SI)

Length

Feet

Meter

Area

Square foot

Square meter

Luminance Flux

Lumens

Lumens

Illumination Flux Density

Foot candles

Lux

Luminance

Foot lamberts

Lambert or Milli-Lamberts

 Recommended Lux Level:

 

Illumination Level
Area Lux Level
Very Bright Summer Day (Max) Up to 100000 Lux
Very Bright Summer Day (Min) 20000 Lux
Nighttime Car Park 1 Lux
Nighttime Urban Street 10 Lux
Night Light on a Building 60 Lux
Machine shop 400 Lux
Offices 500 Lux
Kitchens (food preparation area) 400 Lux
Counters 240 Lux
Machine shop 700 Lux
Canteens 300 Lux
Waiting Rooms 80 Lux
Foyers 200 Lux
Entrance halls 160 Lux
Stairs 40 Lux
Warehouses 80 Lux
Passageways 80 Lux
Corridors 40 Lux

 

            Illuminance for Various Roadway Types (ANSI/IES RP-8)

Road Type Illuminace Lux
Urban Freeway 10
Freeway Interchange 14
Commercial Arterial 20
Residential Collector 8
Local 6

 

Light levels as per IS 1944

Classification of road Type of road Average level of illumination (lux) Min:Avg Min:Max (%)
Group A1 Important traffic routes carrying fast traffic 30 0.4 33
Group A2 Other main roads carrying mixed traffic, like main city streets, arterial roads, throughways etc 15 0.4 33
Group B1 Secondary roads with considerable traffic like principal local traffic routes, shopping streets etc 8 0.3 20
Group B2 Secondary roads with light traffic. important traffic routes carrying fast traffic 4 0.3 20

 

Minimum Level of illumination in Lux

Road Residential Industrial Commercial
Arterial Roads 10.0 13.0 17
Collector Road 6.0 10.0 13.0
Local Roads 4.0 7.0 9.0
Walkways & Pathways 4.0    
Lanes 4.0 2.0 2.0

 

Recommended Levels of Illumination (BIS, 1981)Table 6

Road Characteristics Avg Illumination (Lux) Min / Avg Illumination (Lux) Type of Luminaries Preferred
Important traffic routes carrying fast traffic 30 0.4 Cutoff
Main roads carrying mixed traffic like city main roads/streets, arterial roads, throughways 15 0.4 Cutoff
Secondary roads with considerable traffic like local traffic routes, shopping streets 8 0.3 Cutoff or semi-cutoff
Secondary roads with light traffic 4 0.3 Cutoff or semi-cutoff

 

Recommended Average Horizontal Illumination level in Lux

Pedestrian Traffic

Vehicular traffic Classification

Very light Light Medium Heavy to Heaviest
Heavy 9.68 12.91 16.14 12.52
Medium 6.46 8.61 10.26 12.91
Light 2.15 4.30 6.46 9.68

 

Short Circuit Current Calculation (Base KVA Method)


Example:

Calculate Fault current at each stage of following Electrical System SLD having details of.

  • Main Incoming HT Supply Voltage is 6.6 KV.
  • Fault Level at HT Incoming Power Supply is 360 MVA.
  • Transformer Rating is 2.5 MVA.
  • Transformer Impedance is 6%.

UntitledCalculation:

  • Let’s first consider Base KVA and KV for HT and LT Side.
  • Base KVA for HT side (H.T. Breaker and Transformer Primary) is 6 MVA
  • Base KV for HT side (H.T. Breaker and Transformer Primary) is 6.6 KV
  • Base KVA for LT side (Transformer Secondary and down Stream) is 2.5 MVA
  • Base KV for LT side (Transformer Secondary and down Stream) is 415V

Fault Level at HT Side (Up to Sub-station):

(1) Fault Level from HT incoming Line to HT Circuit Breaker

  • HT Cable used from HT incoming to HT Circuit Breaker is 5 Runs , 50 Meter ,6.6KV 3 Core 400 sq.mm Aluminum Cable , Resistance of Cable 0.1230 Ω/Km and Reactance of Cable is0.0990 Ω/Km.
  • Total Cable Resistance(R)= (Length of Cable X Resistance of Cable) / No of Cable.
  • Total Cable Resistance=(0.05X0.1230) / 5
  • Total Cable Resistance=0.001023 Ω
  • Total Cable Reactance(X)= (Length of Cable X Reactance of Cable) / No of Cable.
  • Total Cable Reactance=(0.05X0.0990) / 5
  • Total Cable Reactance =0.00099 Ω
  • Total Cable Impedance (Zc1)=√(RXR)+(XxX)
  • Total Cable Impedance (Zc1)=0.0014235 Ω——–(1)
  • U Reactance at H.T. Breaker Incoming Terminals (X Pu)= Fault Level / Base KVA
  • U Reactance at H.T. Breaker Incoming Terminals (X Pu)= 360 / 6
  • U. Reactance at H.T. Breaker Incoming Terminals(X Pu)= 0.01666 PU——(2)
  • Total Impedance up to HT Circuit Breaker (Z Pu-a)= (Zc1)+ (X Pu) =(1)+(2)
  • Total Impedance up to HT Circuit Breaker(Z Pu-a)=0.001435+0.01666
  • Total Impedance up to HT Circuit Breaker (Z Pu-a)=0.0181 Ω.——(3)
  • Fault MVA at HT Circuit Breaker= Base MVA / Z Pu-a.
  • Fault MVA at HT Circuit Breaker= 6 / 0.0181
  • Fault MVA at HT Circuit Breaker= 332 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 332 / 6.6
  • Fault Current at HT Circuit Breaker = 50 KA

(2) Fault Level from HT Circuit Breaker to Primary Side of Transformer

  • HT Cable used from HT Circuit Breaker to Transformer is 3 Runs , 400 Meter ,6.6KV 3 Core 400 sq.mm Aluminium Cable , Resistance of Cable 0.1230 Ω/Km and Reactance of Cable is0.0990 Ω/Km.
  • Total Cable Resistance(R)= (Length of Cable X Resistance of Cable) / No of Cable.
  • Total Cable Resistance=(0.4X0.1230) / 3
  • Total Cable Resistance=0.01364 Ω
  • Total Cable Reactance(X)= (Length of Cable X Reactance of Cable) / No of Cable.
  • Total Cable Reactance=(0.4X0.0990) / 5
  • Total Cable Reactance =0.01320 Ω
  • Total Cable Impedance (Zc2)=√(RXR)+(XxX)
  • Total Cable Impedance (Zc2)=0.01898 Ω——–(4)
  • U Impedance at Primary side of Transformer (Z Pu)= (Zc2 X Base KVA) / (Base KV x Base KVx1000)
  • U Impedance at Primary side of Transformer (Z Pu)= (0.01898X6) /(6.6×6.6×1000)
  • U Impedance at Primary side of Transformer (Z Pu)= 0.0026145 PU——(5)
  • Total Impedance(Z Pu)=(4) + (5)
  • Total Impedance(Z Pu)=0.01898+0.0026145
  • Total Impedance(Z Pu)=0.00261——(6)
  • Total Impedance up to Primary side of Transformer (Z Pu-b)= (Z Pu)+(Z Pu-a) =(6)+(3)
  • Total Impedance up to Primary side of Transformer (Z Pu-b)= 0.00261+0.0181
  • Total Impedance up to Primary side of Transformer (Z Pu-b)=0.02070 Ω.—–(7)
  • Fault MVA at Primary side of Transformer = Base MVA / Z Pu-b.
  • Fault MVA at Primary side of Transformer = 6 / 0.02070
  • Fault MVA at Primary side of Transformer = 290 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 290 / 6.6
  • Fault Current at Primary side of Transformer = 44 KA

(3) Fault Level from Primary Side of Transformer to Secondary side of Transformer:

  • Transformer Rating is 2.5 MVA and Transformer Impedance is 6%.
  • % Reactance at Base KVA = (Base KVA x % impedance at Rated KVA) / Rated KVA
  • % Reactance at Base KVA = (2.5X6)/2.5
  • % Reactance at Base KVA =6%
  • U. Reactance of the Transformer(Z Pu) =% Reactance /100
  • U. Reactance of the Transformer(Z Pu)= 6/100=0.06 Ω—–(8)
  • Total P.U. impedance up to Transformer Secondary Winding(Z Pu-c)=(Z Pu)+(Z Pu-b)=(7)+(8)
  • Total P.U. impedance up to Transformer Secondary Winding(Z Pu-c)=0.06+0.02070
  • Total P.U. impedance up to Transformer Secondary Winding(Z Pu-c)=0.0807 Ω—–(9)
  • Fault MVA at Transformer Secondary Winding = Base MVA / Z Pu-c
  • Fault MVA at Transformer Secondary Winding = 2.5/0.0807
  • Fault MVA at Transformer Secondary Winding =31 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 31 / (1.732×0.415)
  • Fault Current at Transformer Secondary Winding = 43 KA

Fault Level at LT Side (Sub-station to Down stream):

(4) Fault Level from Transformer Secondary to Main LT Panel

  • LT Cable used from Transformer Secondary to Main LT Panel is 13 Runs , 12 Meter , 1KV, 3.5C x 400 Sq.mm Aluminium Cable , Resistance of Cable 0.1230 Ω/Km and Reactance of Cable is0.0618 Ω/Km.
  • Total Cable Resistance(R)= (Length of Cable X Resistance of Cable) / No of Cable.
  • Total Cable Resistance=(0.012X0.1230) / 13
  • Total Cable Resistance=0.00009 Ω
  • Total Cable Reactance(X)= (Length of Cable X Reactance of Cable) / No of Cable.
  • Total Cable Reactance=(0.012X0.0618) / 13
  • Total Cable Reactance =0.00006 Ω
  • Total Cable Impedance (Zc3)=√(RXR)+(XxX)
  • Total Cable Impedance (Zc3)=0.00011 Ω——–(10)
  • U Impedance at Main LT Panel (Z Pu)= (Zc3 X Base KVA) / (Base KV x Base KVx1000)
  • U Impedance at Main LT Panel (Z Pu)= (0.00011X2.5×1000)/(0.415×0.415X1000)
  • P P.U Impedance at Main LT Panel (Z Pu)= 001601 Ω ——(11)
  • Total Impedance up to Main LT Panel (Z Pu-d)= (Zc3)+ (Z Pu-c) =(11)+(9)
  • Total Impedance up to Main LT Panel (Z Pu-d)= 0.001601 +0.0807
  • Total Impedance up to Main LT Panel (Z Pu-d)=0.082306 Ω.——(12)
  • Fault MVA at Main LT Panel = Base MVA / Z Pu-a.
  • Fault MVA at Main LT Panel = 2.5 / 0.082306
  • Fault MVA at Main LT Panel = 30 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 30 / (1.732X0.415)
  • Fault Current at Main Lt Panel = 42 KA

(5) Fault Level from Main LT Panel to Sub Panel:

  • LT Cable used from Main LT Panel to Sub Panel is 2 Runs , 160 Meter , 1KV, 3.5C x 400 Sq.mm Aluminium Cable , Resistance of Cable 0.1230 Ω/Km and Reactance of Cable is0.0618 Ω/Km.
  • Total Cable Resistance(R)= (Length of Cable X Resistance of Cable) / No of Cable.
  • Total Cable Resistance=(0.160X0.1230) / 2
  • Total Cable Resistance=0.008184 Ω
  • Total Cable Reactance(X)= (Length of Cable X Reactance of Cable) / No of Cable.
  • Total Cable Reactance=(0.160X0.0618) / 2
  • Total Cable Reactance =0.004944 Ω
  • Total Cable Impedance (Zc4)=√(RXR)+(XxX)
  • Total Cable Impedance (Zc4)=0.0095614 Ω——–(13)
  • U Impedance at Sub Panel (Z Pu)= (Zc4 X Base KVA) / (Base KV x Base KVx1000)
  • U Impedance at Sub Panel (Z Pu)= (0.0095614 X2.5×1000)/(0.415×0.415X1000)
  • P P.U Impedance at Sub Panel (Z Pu)= 13879 Ω ——(14)
  • Total Impedance up to Sub Panel (Z Pu-e)= (Zc4)+ (Z Pu-d) =(14)+(12)
  • Total Impedance up to Sub Panel (Z Pu-e)= 0.13879 +0.082306
  • Total Impedance up to Sub Panel (Z Pu-e)=0.2211 Ω.——(15)
  • Fault MVA at Sub Panel = Base MVA / Z Pu-a.
  • Fault MVA at Sub Panel = 2.5 / 0.2211
  • Fault MVA at Sub Panel = 11 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 11 / (1.732X0.415)
  • Fault Current at Sub Panel = 16 KA

(6) Fault Level from Sub Panel to Motor Control Panel:

  • LT Cable used from Sub Panel to Motor Control Panel is 6 Runs , 150 Meter , 1KV, 3.5C x 400 Sq.mm Aluminium Cable , Resistance of Cable 0.1230 Ω/Km and Reactance of Cable is0.0739 Ω/Km.
  • Total Cable Resistance(R)= (Length of Cable X Resistance of Cable) / No of Cable.
  • Total Cable Resistance=(0.150X0.1230) / 6
  • Total Cable Resistance=0.003075 Ω
  • Total Cable Reactance(X)= (Length of Cable X Reactance of Cable) / No of Cable.
  • Total Cable Reactance=(0.150X0.0739) / 6
  • Total Cable Reactance =0.0018475 Ω
  • Total Cable Impedance (Zc5)=√(RXR)+(XxX)
  • Total Cable Impedance (Zc4)=0.003587 Ω——–(16)
  • U Impedance at Motor Control Panel (Z Pu)= (Zc5 X Base KVA) / (Base KV x Base KVx1000)
  • U Impedance at Motor Control Panel (Z Pu)= (0.003587 X2.5×1000)/(0.415×0.415X1000)
  • P P.U Impedance at Motor Control Panel (Z Pu)= 05207 Ω ——(17)
  • Total Impedance up to Motor Control Panel (Z Pu-f)= (Zc5)+ (Z Pu-e) =(17)+(15)
  • Total Impedance up to Motor Control Panel (Z Pu-e)= 0.13879 +0.2211
  • Total Impedance up to Motor Control Panel (Z Pu-e)=0.27317 Ω.——(15)
  • Fault MVA at Motor Control Panel = Base MVA / Z Pu-a.
  • Fault MVA at Motor Control Panel = 2.5 / 0.27317
  • Fault MVA at Motor Control Panel = 9 MVA
  • Fault Current = Fault MVA / Base KV
  • Fault Current = 9 / (1.732X0.415)
  • Fault Current at Motor Control Panel = 13 KA

 Summary of Calculation:

Sr.No Fault Location Fault MVA Fault Current (KA)

1

At HT Circuit Breaker

332

50

2

At Primary Side of Transformer

290

44

3

At Secondary Side of Transformer

31

43

4

At Main LT Panel

30

42

5

At Sub Main Panel

11

16

6

At Motor Control Panel

9

13

 

Motor Name Plate Terminology


General Terminology

(1) Service Factor:

  • The service factor is a multiplier that indicates the amount of overload a motor can be expected to handle. If a motor with a 1.15 service factor can be expected to safely handle intermittent loads amounting to 15% beyond its nameplate horsepower.
  • For example, many motors will have a service factor of 1.15, meaning that the motor can handle a 15% overload. The service factor amperage is the amount of current that the motor will draw under the service factor load condition.

(2) Slip:

  • Slip is used in two forms. One is the slip RPM which is the difference between the synchronous speed and the full load speed. When this slip RPM is expressed as a percentage of the synchronous speed, then it is called percent slip or just “slip”. Most standard motors run with a full load slip of 2% to 5%.

(3) Synchronous Speed:

  • This is the speed at which the magnetic field within the motor is rotating. It is also approximately the speed that the motor will run under no load conditions. For example, a 4 pole motor running on 60 cycles would have a magnetic field speed of 1800 RPM. The no load speed of that motor shaft would be very close to 1800, probably 1798 or 1799 RPM. The full load speed of the same motor might be 1745 RPM. The difference between the synchronous speed and the full load speed is called the slip RPM of the motor.

Untitled

Motor Torque:

(1) Pull Up Torque:

  • When the motor starts and begins to accelerate the torque in generally decrease until it reach a low point at a certain speed it called the pull-up torque.
  • The Pull-up Torque is the minimum torque developed by the electrical motor when it runs from zero to full-load speed (before it reaches the break-down torque point).
  • Pull-up torque is the minimum torque developed during the period of acceleration from locked-rotor to the speed at which breakdown torque occurs.
  • Some motor designs do not have a value of pull up torque because the lowest point may occur at the locked rotor point. In this case, pull up torque is the same as locked rotor torque.
  • For motors which do not have a definite breakdown torque (such as NEMA design D) pull-up torque is the minimum torque developed up to rated full-load speed. It is usually expressed as a percentage of full-load torque.

(2) Starting Torque (Locked Rotor Torque):

  • The amount of torque the motor produces when it is energized at full voltage and with the shaft locked in place is called starting torque.
  • The Locked Rotor Torque or Starting Torque is the torque the electrical motor develop when its starts at rest or zero speed.
  • It is the amount of torque available when power is applied to break the load away and start accelerating it up to speed.
  • A high Starting Torque is more important for application or machines hard to start – as positive displacement pumps, cranes etc. A lower Starting Torque can be accepted in applications as centrifugal fans or a pump where the start loads is low or close to zero.

 (3) Full Load Torque:

  • Full load torque is the rated continuous torque that the motor can support without overheating within its time rating.
  • In imperial units the Full-load Torque can be expressed as
  • T full-load torque (lb ft) = (Rated horsepower of Motor X 5252) / Rated rotational speed (rpm)       
  • In metric units the rated torque can be expressed as
  • Full-load torque (Nm) = (Rated KW of Motor X 9550) / Rated rotational speed (rpm)
  • Example :The torque of a 60 hp motor rotating at 1725 rpm can be expressed as
  • T full-load torque = 60 X 5,252 / 1725 (rpm)
  • T full-load torque = 182.7 lb ft

(4) Peak Torque:

  • Many types of loads such as reciprocating compressors have cycling torques where the amount of torque required varies depending on the position of the machine.
  • The actual maximum torque requirement at any point is called the peak torque requirement.
  • Peak torques is involved in things such as punch presses and other types of loads where an oscillating torque requirement occurs.

(5) Pull out Torque (Breakdown Torque):

  • Breakdown torque is the maximum torque the motor will develop with rated voltage applied at rated frequency without an abrupt drop in speed. Breakdown torque is usually expressed as a percentage of full-load torque
  • The load is then increased until the maximum point is reached.

Motor Current:

(1) Full Load Amps:

  • The amount of current the motor can be expected to draw under full load (torque) conditions is called Full Load Amps. It is also known as nameplate amps.

(2) Locked Rotor Amps:

  • Also known as starting inrush, this is the amount of current the motor can be expected to draw under starting conditions when full voltage is applied.
  • Lock Rotor Current (IL) Three Phase Motor: 1000x HP x (KVA/HP) / 1.732 x Volt
  • Lock Rotor Current (IL) Single Phase Motor: 1000x HP x (KVA/HP) / Volt

 

Thumb Rule-11


 

Size of Cable on Secondary Side of Transformer (11KV/433V)
Ref: KSEI Handbook
Rating of T/C (KVA) Primary current (Amp) Secondary Current (Amp) Min. Size of Neutral Earthing Conductor (mm2) Minimum Size of Cable (mm2)
63 3.3 84 25X3 50mm2
100 5.25 133.3 25X3 95mm2 or (2×50 mm2)
160 8.4 213.3 25X3 185mm2 or (2×95 mm2)
200 10.49 266.6 25X3 300mm2 or (2×120 mm2)
250 13.12 333 25X3 2×185 mm2
315 16.53 420 31X3 or 25X4 (2×300 mm2) or (3×185 mm2)
400 21.80 533 38X3 (3×300 mm2) or (2×400 mm2)
500 26.20 666.5 25X6 (3×400 mm2) or (4×240 mm2)
630 33 840 31X6 4×400 mm2
750 39.36 1000 50X4 Bus Bar Trucking (min. Isc 50KA)
1000 52.50 1333 210mm2 Bus Bar Trucking (min. Isc 50KA)
1250 65.50 1667 290mm2 Bus Bar Trucking (min. Isc 50KA)
1600 83.98 2133 380mm2 Bus Bar Trucking (min. Isc 50KA)
2000 105.00 2666 450mm2 Bus Bar Trucking (min. Isc 50KA)

 

HT Fuse on Primary Side of Transformer (11KV/433V)
Rating of T/C (KVA) Primary current (Amp) Secondary Current (Amp) HT Fuse
Min (Amp) Max(Amp)
63 3.3 84 10 16
100 5.25 133.3 16 25
160 8.4 213.3 16 40
200 10.49 266.6 25 40
250 13.12 333 32 40
315 16.53 420 40 63
400 21.80 533 40 63
500 26.20 666.5 50 100
630 33 840 63 100
750 39.36 1000 75 160
1000 52.50 1333 100 160
1250 65.50 1667 100 200
1600 83.98 2133 160 250
2000 105.00 2666 200 250

 

Capacitor Bank for Power Supply Voltage
System Voltage Minimum rating of capacitor bank
3.3 KV , 6.6KV 75 Kvar
11 KV 200 Kvar
22 KV 400 Kvar
33 KV 600 Kvar

 

Capacities of PVC conduits
Nominal conductor Size mm 16 mm 20 mm 25 mm 32 mm
Number of Cables (maximum)
1.0 6 5 19 30
1.5 5 4 15 24
2.5 3 3 11 17
4 2 2 8 13
6 2 - 6 10
10 - - 4 6
16 - - 3 4
25 - - 2 3
35 - - - 2

 

System Highest and Lower Voltage
Ref: NEC(India) :2011
System Voltage Highest Voltage Lowest Voltage
240 V 264 V 216 V
415 V 457 V 374 V
3.3 kV 3.6 kV 3.0 kV
6.6 kV 7.2 kV 6.0 kV
11 kV 12 kV 10 kV
22 kV 24 kV 20 kV
33 kV 36 kV 30 kV
66 kV 72.5 kV 60 kV
66 kV 72.5 kV 60 kV
132 kV 145 kV 120 kV
220 kV 245 kV 200 kV
400 kV 420 kV 380 kV

 

Number of Points for Dwelling Unit
Ref: NEC(India) :2011
No. Description Area for the Main Dwelling Unit (m2)
35 mm2 45 mm2 55 mm2 85 mm2 140 mm2
1 Light points 7 No 8 No 10 No 12 No 17 No
2 Ceiling fans Pont 2 No 3 No 4 No 5 No 7 No
3 Ceiling fans No’s 2 No 2 No 3 No 4 No 5 No
4 6A Socket outlets 2 No 3 No 4No 5 No 7 No
5 16A Socket outlets - 1 No 2 No 3 No 4No
6 Call-bell (buzzer) - - 1 No 1 No 1 No

 

Recommended Schedule of Socket-Outlets
Ref: NEC(India) :2011
Description Number of Socket
6A Socket 16A Socket
Bedroom 2 1
Living room 2 2
Kitchen 1 2
Dining room 2 1
Garage 1 1
For refrigerator - 1
For air-conditioner - 1 for each
Verandah 1 per 10mter2 1
Bathroom 1 1

 

Power requirements of the building
Ref: NEC(India) :2011
Part of ElectricalInstallation Part of the Total Power Requirement in % DiversityFactor
Ventilation, heating (air-conditioning) 45% 1.0
Power plant (drives) 52% 0.65
Lighting 30% 0.95
Lifts 20% 1.0
Kitchen 10% 0.6
Laundry 5% 0.6

 

Lift Car Speed
Ref: NEC(India) :2011
Occupancy No. of Floors Served Car Speed   m/s
Office building 4 to 5 0.5 to 0.75 m/sec
Office building 6 to 12 0.75 to 1.5 m/sec
Shops and departmental stores 13 to 20 More than 1.5 m/sec
Passenger lifts for low and medium lodging houses - 0.5 m/sec
Hotels 4 to 5 0.5 to 0.75 m/sec
Normal load carrying lifts - 2.0 to 2.5 m/sec
Hospital passenger Lift 4 to 5 0.5 to 0.75 m/sec
Hospital passenger Lift 13 to 20 More than 1.5 m/sec
Hospital bed lifts (Short travel lifts insmall hospitals) - 0.25 m/sec
Hospital bed lifts (Normal) - 0.5 m/sec
Hospital bed lifts (Long travel lifts inGeneral hospitals)   0.6 to 1.5 m/sec

 

Capacitor Ratings at Rated Voltage
Ref: NEC(India) :2011
Motor Rating(Kw) Capacitor Rating in kVAR for Motor Speed
3 000rev/min 1 500rev/min 1 000rev/min 750rev/min 600rev/min 500rev/min
2.25 1 1 1.5 2 2.5 2.5
3.7 2 2 2.5 3.5 4 4
5.7 2 3 3.5 4.5 5 5.5
7.5 3 4 4.5 5.5 6 6.5
11.2 4 5 6 7.5 8.5 9
15 5 6 7 9 11 12
18.7 6 7 9 10.5 13 14.5
22.5 7 8 10 12 15 17
37 11 12.5 16 18 23 25
57 16 17 21 23 29 32
75 21 23 26 28 35 40
102 31 33 36 38 45 55
150 40 42 45 47 60 67
187 46 50 53 55 68 76

 

:Maximum Current Demand for Motor:
Ref: NEC(India) :2011
Nature of supply Size of installation Maximum current demand
Single phaseor Three phase Up to and including 0.75 kW Six times the full load current
Above 0.75 kW and up to 7.5 kW Three times the full load current
Above 7.5 kW up to and up to11 kW Two times the full load current
Above 11 kW One and half times the full load current

 

Rated Basic Insulation Level (BIL)
Ref: NEC(India) :2011
Nominal System Voltage (kV) Rated BIL (kVp)
33 KV 170
22 KV 125
11 KV 75
6.6 KV 60
3.3 KV 40

 

Illumination Level
Ref: NEC(India) :2011
Location Illumination Level (Lux)
Residence
Entrance / Hallways 100
Living room 300
Dining Room 150
Bed Room (General) 300
Bed Room (Dressing , Bed Heads) 200
Kitchen 200
Kitchen sink 300
Bathroom 100
Sewing 700
Workshop 200
Staircase 100
Garage 70
Study Room 300
Office Building
Entrance hall / Reception 150
Conference Room / Executive Office 300
General Office Space 300
Business Machinery Operation 450
Drawing Office 450
Corridors 70
Stairs 100
Lift landing 150
Hospital Building
Reception & Waiting 150
General ward 100
Bed Side 150
Toilet 70
Stairs 100
Operation Theatre (General) 300
Operation Theatre (Operation Table) Special
Laboratories 300
Radiology 100
Causality 150
Dispensaries 300
Laundry 200
Dry Cleaning 200
Ironing 300
General Office 450
Kitchen 200
Assembly & Concert Halls
Foyers 100 to 150
Auditoria 100 to 150
Platform 450
Corridors 70
Stairs 100
Cinema Halls
Foyers 150
Auditoria 50
Corridors 70
Stairs 100
Theatres
Foyers 150
Auditoria 70
Corridors 70
Stairs 100
School / College Building
Assembly Halls  
General 150
Examination center 300
Platform 300
Classes  
Desktop 300
Blackboard 200 to 300
Libraries  
Shelves 70 to 150
Reading Room 150 to 300
Reading Table 300 to 700
Cataloguing 150 to 300
General  
Office 300
Staff Room 150
Corridors 70
Stairs 100

 

Lamp’s Lumen Data
Rating (Watt) Life (Hours) Initial Lumens
Incandescent Lamp
60 1000 870
100 750 1750
150 2000 1740
200 2000 2300
500 2000 6500
Fluorescent Lamp
18 7000 1120
20 7000 1020
36 7000 2800
40 7000 2700
2X40 7000 4000
Compact Fluorescent Lamp
5 10000 220
7 7000 380
11 7000 560
13 7000 680
15 7000 810
18 7000 1050
23 7000 1500
26 7000 1800
32 7000 2400
Mercury Vapour Lamp
100 18000 3700
175 24000 8600
250 24000 12100
400 24000 22500
1000 24000 57000
Metal Halide Lamp
50 15000 3400
70 15000 5600
100 15000 9000
150 10000 13500
175 10000 15000
250 10000 20500
400 20000 36000
1000 12000 110000
High Pressure Sodium Vapour Lamps
35 16000 2250
50 24000 4000
70 24000 5800
100 24000 9500
150 24000 16000
250 24000 27500
400 24000 47500
1000 24000 140000
Pulse Start Metal Halide Lamp
50 15000 3400
70 15000 5600
100 15000 9000
150 15000 15000
175 15000 17500
200 15000 21000
250 15000 26300
320 20000 34000
400 20000 44000
450 20000 50000

 

:Duty Type of Motor:
Ref: IS-325
Duty Type Symbol Duty Type Application
S1 Continuous Duty Pumps, Bowers, Compressors, Fans
S2 Short Time Duty Siren, Flood relief Gates
S3 Intermittent Periodic Duty Valve, Actuators, Wire drawing machine
S4 Intermittent Periodic Duty with starting Hoist, Cranes, Lifts, Escalators
S5 Intermittent Periodic Duty with starting / Breaking Hoist, Cranes (with electronics Breaks), Rolling mills
S6 Continuous Duty with Intermittent Periodic Duty Machine tools, Conveyors
S7 Continuous Duty with starting / Breaking Machine tools,
S8 Continuous Duty with periodic load changes Pole Channing Applications

 

Type of Distribution System
As per IEC 60364-3
Unearthed System Earthed System
IT TT / TN (TN-S,TN-C,TN-C-S)
First Letter (the neutral point in relation to earth):T= directly earthed neutral (from the French word Terre)I =unearthed or high impedance-earthed neutral (e.g. 2,000 Ω)
Second letter (Exposed conductive parts of the electrical installation in relation to earth):T =directly earthed exposed conductive partsN =exposed conductive parts directly connected to the neutral conductor

 

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