Posts

Showing posts from 2016

Activity 5: Schedule of quantity for the work "Replacement of LT Panel"

Name of work: Replacement of LT electrical panel. Schedule of quantity Sl. No. Description of item Unit Quantity Rate (Rs.) Amount (Rs.) 1 Decommissioning & dismantling of the existing 415V, 1200 amps, main LT panel  and sub panel totally and shifting it to a suitable location in Electrical sub-station as per the directions of engineer-in-charge. The work also includes minor civil works, disconnection of all the incoming cables and outgoing cables from the existing LT panel, cleaning the trenches together with cost of labour, transport, tools &plants, stacking of serviceable materials complete. Lump sum 1 job 50000.00 50000.00 2 Supply, erection, testing & commissioning of indoor type Main LT Panel, floor mounting type, dust and vermin proof by construction of 14 SWG CRCA sheets compartmentalized, modular type IP42 protection with powder coated panel  ...

Effects of electrical energy

Electrical energy has following effects: 1. Biological effect: Electrical energy has effect on biological cells. Electrical current through human body or living beings produces biological reactions. Example: electrical shock. 2. Electro-mechanical effect: Two current carrying conductors have mechanical attraction or repulsion due to the magnetic field produced by them. It may be noted that, electrical energy can be converted to mechanical energy by using motors and mechanical energy can be converted to electrical energy by using generators. 3. Electro-thermal effect: Electrical current passing through a conductor produces heat due to losses. This effect will be normally used in Electric Ovens and Furnaces. 4. Electro chemical effect: Electric current passing through electrolyte produces electrolysis. Example: electroplating.

Rules for writing SI Units

1. Symbols for units are written without capital letters, except when it is derived from name. Example: "t" for time "h" for hour "m" for meter 2. Symbols for units derived from proper name are written in capital. Example: "A" for ampere "W" for watt 3.Full names of units are written with lower case letters only. Example: newton henry 4. A space is left between symbols of compound units. Example: N m 5. A space is left between the number and symbol. Example: 56 J 5 A 6. Only one SI prefix is permitted. Example: kA MJ 7. A symbol should not be followed by a fullstop except when it is a product. Example: kg.m 8. Numerals with more than three digits shall be written without commas and with a narrow spacing at an interval of three digits. Example: 45 006 72 674 9. A number with four figures is not broken as mentioned above. Example: 4321 10. A symbol of a unit is placed after the decimal ...

Multiples and Submultiples of units

Deci (d) : 10^-1 Centi (c): 10^-2 milli (m): 10^-3 micro (u): 10^-6 nano (n): 10^-9 pico (p): 10^-12 femto (f): 10^-15 atto (a): 10^-18 deca (da): 10 hecto (h) :10^2 kilo (k) : 10^3 mega (M): 10^6 giga (G) : 10^9 tera (T) : 10^12 peta (P): 10^15 exa (E) : 10^18

System International Units

1. In which year, the SI (System International d`units) was recommended by the general conference on weights and measures? a) 1966 b) 1959 c) 1960 d) 1961 Ans: c 2. What is the SI Unit of Length? a) second b) gram c) mole d) meter Ans: d 3. What is the SI Unit of Mass? a) mole b) kilogram c) second d) ampere Ans: b 4. What is the unit of Electric current? a) ampere b) Kelvin c) candela d) radian Ans: a 5. Candela is the unit for which quantity? a) Temparature b) Plane angle c) Solid angle d) Luminous Intensity Ans: d 6. Among the following, which one is the supplemantary unit? a) steradian b) mole c) second d) meter Ans: a 7. What is the unit of Solid angle? a) candela b) ammeter c) Kelvin d) steradian Ans: d 8. What is the unit for derived quantity, Area? a) cubic meter b) meter per second c) square meter d) mole per cubic meter Ans: c 9. What is the unit of derived quantity, Luminance (Light)? a) candela per square met...