it radiates a comfortable level of brightness without glare and allows you to see and walk about safely.
perform specific tasks, such as reading, grooming, preparing and cooking food, doing homework
Accent lighting is mainly decorative, intended to highlight pictures, plants, or other elements of interior design or landscaping.
We need a separate unit to measure lightThe total quantity (energy) of visible light emitted by a light source per second (as seen by humans).
The lighting level of a surface is measured by the Illuminance.
A LUMINAIRE IS AN APPARATOR WHICH DISTRIBUTES, FILTERS OR TRANSFORM THE LIGHT EMITTED FROM ONE OR MORE LAMPS.INCLUDES PARTS FOR FIXING- MEANS OF PROTECTING LAMPS - MEANS FOR CONNECTING TO ELECTRICAL SUPPLY
Reflectance is conventionally represented by a figure equal to 10 times the real reflectance: for example, 7 indicate a reflection factor of 0.7 or 70%.
Lumen(Luminous flux) [F]<br /><ul><li>The lumen is defined such that…
At frequency of 540×1012hz, (i.e., at wavelength λ=555nm) 1 watt of radiant flux (power) will emit 683 lumens of light (luminous flux).</li></li></ul><li>Illuminance (E)<br />Defined as the luminous flux (lumens) falling on a surface per unit area normal to the surface.<br />The unit of illuminance is the Lux<br />
Required no. of Luminaries<br /> E x Lx W<br /> N = _______________________<br /> NL x x MF x UF x LLD<br /> E= Required Illuminance (Lux level)<br /> L = Room length (m)<br /> W = Room width (m)<br /> NL = Number of lamps in each luminaries<br /> N = Number of luminaries<br /> = Lamp flux<br /> M = Maintenance factor<br /> UF = Utilization factor<br /> LLD = Lamp Lumen Deterioration factor<br />
Maintanance factor (MF)<br />Can be defined as…<br /> Averageilluminanceon the working plane after a specified period of use of a lighting installation to the averageilluminanceobtained under the same conditions for a new installation. <br />
Reflectance factor<br />the fraction of radiant energy that is reflected from a surface<br />Examples- 70% , 0.8, ...<br />Here 10 times the reflection factor…..<br /> 1.Ceiling <br /> 2. Walls <br /> 3. FloorWorking plane.<br />
Room Index<br />K = (LXW)/ [(H1-H0)X(L+W)]<br />Where,<br />L = Room Length (m)<br />W = Room Width (m)<br />H1 = Height of luminaire’s light emitting surface<br />H0 = Height of the working plan<br />
Part 3<br />Cable selection and Over load Protection<br />
Basic types of MCB’s<br />TYPE B<br />TYPE C<br />TYPE D <br />
Sizing the cables<br />length of the wire <br />Check the following inequality<br /> In<br /> It ___________ and InIb<br /> CaCi CgCf<br /> It = Maximum current capacity of cable for given temp. <br />Ib = Design current <br /> In = Rated current of the protective device<br /> Ca = Correction factor for ambient temperature. <br /> CI = Correction factor for thermal insulation<br /> Cg = Correction factor for grouping<br />Cf = Correction factor for semi enclosed fuse. <br /> (for MCBs Cf = 1)<br />
Contd…<br />Refer IEE wiring regulation book<br />Lesser than 4% voltage drop….<br />
Selecting a protective device<br />Nature of the load<br />Rated current of the conductor<br />Environmental conditions<br />
Contd..<br />Ib rated current of protective diviceIz<br />Where, <br />Ib = Design service current<br />Iz = Maximum current carrying capacity of the conductor<br /> If 1.45 x Iz<br />Where, <br />Iz = Maximum current carrying capacity of the conductor<br /> If = Thermal tripping current of MCCB<br />