Thursday 28 May 2015

LED versus conventional light

LED light may be the right choice today.

What is LED Lighting?
LED lighting uses Light Emitting Diodes (LEDs)

 instead of a filament like in an incandescent bulb. 
LEDs are solid state devices; there is no moving 
parts, chemicals or gases. In built   circuit 
chips are very safe, reliable and efficient.
 Benefits of LED Lighting?
  • LEDs operate at a much higher efficiency than conventional lighting, and also higher than energy saver bulbs. This means that LED lighting will save power and will therefore save our more money than any other bulb.
  • Unlike incandescent or halogen lighting, LED lighting runs cool, so there is no risk of burning or fire hazards.
  • LEDs have a much longer lifetime, where a typical LED bulb lasts up to 50,000 hours compared to typically 30,000 for fluorescent and only 2000 for halogen or incandescent bulbs.
  • LED bulbs turn on instantly unlike the energy saver bulbs which take a while to "warm up".
  • There is no glass to break in most LED bulbs, which makes them safer.
  • LEDs are ideal for use in applications that are subject to frequent on-off cycling, unlike fluorescent lamps that burn out more quickly when cycled frequently.
  • The manufacturer has full control over the colour of light output from LEDs.
  • LEDs do not contain mercury, unlike fluorescent lamps.
How does the Lifespan of an LED Bulb Compare?
LED bulbs last for much MUCH longer than standard bulbs, so although they are more expensive, they pay for themselves many times over their lifetime. Imagine not having to replace your bulbs for 10 years! The following diagram shows how much longer an LED bulb runs for compared to those short living halogens:


How does the Power Consumption of an LED Bulb Compare?
LED bulbs draw much less energy than standard bulbs, The following diagram shows the power consumption of a LED bulb with the equivalent light output of other bulbs. LED bulbs run on about 8-15% of the power.
Operation cost
Energy Efficiency && Energy Costs
Light Emitting Diodes (LEDs)
Light Bulbs
Compact  Fluorescents (CFLs)

Life Span (average)
 50,000 hours
 1,200 hours
8,000hours
Watts of electricity used
LEDs use less power (watts) per unit of light generated (lumens). LEDs help reduce greenhouse gas emissions from power plants and lower electric bills
6 - 8 watts
60W
13-15W
Kilo-watts of Electricity used   
(30 Incandescent Bulbs per year equivalent) 
329 KWh/yr.
3285 KWh/yr.
767 KWh/yr.
Annual Operating Cost   (30 Incandescent Bulbs per year equivalent) 
Rs.1974
@Rs6/- per unit
Rs.19710
Rs.4602

Environmental Impact
Environmental impact

Light Emitting Diodes (LEDs)
Light Bulbs
Compact  Fluorescents (CFLs)
Contains the TOXIC Mercury 
No
No
Yes - Mercury is very toxic to your health and the environment
RoHS Compliant
yes
Yes
No - contains 1mg-5mg of Mercury and is a major risk to the environment
Carbon Dioxide Emissions  (30 bulbs per year), Lower energy consumption decreases: CO2 emissions, sulphur oxide, and high-level nuclear waste. 
204 KG/year
2041 KG/year
476.5 KG/year

Important Fact

Light Emitting Diodes (LEDs)
Light Bulbs
Compact  Fluorescents (CFLs)
Sensitivity to low temperatures
None
Some
Yes - may not work under negative 10 degrees Fahrenheit or over 120 degrees Fahrenheit
Sensitive to humidity
No
Some
Yes

On/off Cycling Switching a CFL on/off quickly, in a closet for instance may decrease the lifespan of the bulb.
No Effect

Yes  - can reduce lifespan drastically
Turns on instantly
Yes
Yes
No - takes time to warm up
Durability
Very Durable - LEDs can handle jarring and bumping
Not Very Durable - glass or filament can break easily
Not Very Durable - glass can break easily
Heat Emitted
3.4 btu's/hour
85 btu's/hour
30 btu's/hour
Failure Modes 
Not typical
Some
Yes - may catch on fire, smoke, or omit an odor

Light output

Light Emitting Diodes (LEDs)
Light Bulbs
Compact  Fluorescents (CFLs)
Lumens
watts
watts
watts
450
4-5
40
9-13
800
6-8
60
13-15
1100
9-13
75
18-25
1600
16-20
100
23-30
2600
25-28
150
30-55

Mercury in CFLs
We are pushing more mercury into environment by using Tube light and CFL. Some of our electricity is produced by coal-fuelled power plants that release mercury into the environment. Using CFLs uses less electricity and results in fewer mercury emissions, as compared to incandescent lamp:
Conclusion:
LEDs are competitive, Eco friendly, and likely to go better. LEDs lighting technology is still growing and improving drastically.



Friday 22 May 2015

space requirement for transformer

1     Space requirement for transformer 

SPACE REQUIRED FOR TRANSFORMER INSTALLATION 

Area for transformer room: (As per NBC-2005)
Transformer Size   Min. Transformer Room Area (M2)    Min. Total Sub Station
Area( Incoming HV,LV Panel, T.C Roof)    (M2)       Min. Space           Width (Meter)
1 x 160                                                            14                    90                                9
2 x 160                                                            28                    118                              13.5
1 x 250                                                            15                    91                                9
2 x 250                                                            30                    121                              13.5
1 x 400                                                            16.5                 93                                9
2 x 400                                                            33                    125                              13.5
3 x 400                                                            49.5                 167                              18
2 x 500                                                            36                    130                              14.5
3 x 500                                                            54                    172                              19
2 x 630                                                            36                    132                              14.5
3 x 630                                                            54                    176                              19
2 x 800                                                            39                    135                              14.5
3 x 800                                                            58                    181                              14
2 x 1000                                                          39                    149                              14.5
3 x 1000                                                          58                    197                              19


- The capacitor bank should be automatically switched type for substation of 5MVA and higher.
 - Transformer up to 25 KVA can be mounted direct on pole.
 - Transformer from 25 KVA to 250KVA can be mounted either on “H” frame of plinth.
 - Transformer above 250 KVA can be mounted plinth only.

 - Transformer above 100 MVA shall be protected by drop out fuse or circuit breaker.

Earthing guideline for hazardous area

Earthing guideline in hazardous area
Earthing is required for –
·         Safety of working personnel
·         Equipment safety
·         Protection against fault

earthing in hazardous location

Size of earth conductor
Sr.no.
Type of equipment
Earth conductor size
1
Street light poles
10 mm dia solid GI wire rope
2
Motor upto 3.7KW
8 SWG solid GI wire
3
Motor upto 5.5KW to 30KW & welding receptacle
10 mm dia solid GI wire rope
4
Motor above 37KW including HT motor
16 mm dia solid GI wire rope / 40mm x5 mm GI strip
5
Building columns
40mm x 5 mm GI strip
6
Storage tank vertical or horizontal
40mm x 5 mm GI strip
7
Loading racks
40mm x 5 mm GI strip
8
Pipe racks, heat exchanger, Vessel
40mm x 5 mm GI strip
9
Small equipments and instruments
8 SWG solid GI rope
10
Lighting, power and instrument panel
10 mm dia solid GI wire rope
11
Main earth bus /MV &HV switchgear interconnection /power transformer
As per calculation
12
EHV/HV substation
As per calculation
13
Push button station
8 SWG solid GI wire
14
Bonding of pipe
25 mm2 insulated flexible copper cable
15
Lighting transformer
16 mm dia solid GI wire rope
General:
1. Earth connections to individual equipment from nearest earth plate/ grid may also be done alternatively using Aluminum/ Copper conductor PVC insulated core of size not less than half the cross-section of respective power cable to the equipment (Motor, Panel etc.). Connections shall be made using crimped type of lugs.
2. Earth rods and conductors shall be designed to cope with the conditions imposed. The earth conductor shall be adequately sized to carry the applicable maximum earth fault current without undue temperature rise. All joints shall be protected against corrosion.
3. All the electrical equipment operating above 250 volts shall have two separate and distinct connections to earth grid.
4. Lighting Fixtures shall be earthed through the extra core provided in the lighting cable.

5. The cross sectional area of earthing conductor shall be minimum 4 sqmm.

One Nation, One electrical License

Electrical contractors are facing license problem when they bid for another state. Generally they are entitled to do work in particular stat...