Latest articles

Hydrogen Energy and Fuel Cells

Published on January 25, 2015

Hydrogen is a colourless, odourless, tasteless and flammable gas. Hydrogen has highest energy content per unit mass of 120.7 MJ/kg among known fuels

Read full article...

India's National Action Plan on Climate Change

Published on December 8, 2013

The following are the guiding principles of NAPCC—protecting the poor and vulnerable sections of society through an inclusive and sustainable development strategy, sensitive to climate change, achieving national growth objectives through a qualitative change in direction that enhances ecological sustainability, leading to further mitigation of greenhouse gas emission, devising efficient and cost-effective strategies for...

Read full article...

Energy Conservation

Published on December 1, 2013

As per Wikipedia, energy conservation refers to reducing energy through using less of an energy service. Energy conservation differs from efficient energy use, which refers to using less energy for a constant service . For example, using a bulb for lesser hours...

Read full article...

Energy Conservation Building Code

Published on November 24, 2013

Energy conservation aspect has not been a factor in building design in India. Buildings has been designed for its aesthetics, cost, uniqueness and saleability. This has resulted into tremendous increase in operating energy cost. Energy Ceonservation Building Code (ECBC) is a step forward for...

Read full article...

Energy Conservation Act

Published on November 17, 2013

Energy Management Center (EMC) was set up in 1989, with a mandate to promote energy efficiency and energy conservation. EMC created initial awareness of energy conservation. In 1997, Ministry of Power realized to strenghten EMC with statutory powers to promote energy conservation, considering the vast potential of energy saving and benefits of energy efficiency...

Read full article...

Utilization Factor of Liminaires

Published on November 10, 2013

Utilization factor tables of luminaries are...

Read full article...

Ventilation Systems

Published on November 3, 2013

Size of a ceiling fan should be chosen based on the actual working area and not on the basis of total room area so that unnecessary energy is not wasted. The design criterion based on number of air changes results in excess requirement. For a working zone with longer dimension...

Read full article...

Selection of Lamps

Published on October 27, 2013

The first step in the selection of lamp is to select the range of lamps satisfying the quality requirements such as colour properties, glare etc. and then select the lamp which has the highest efficacy within the group. Selection criterion are...

Read full article...

Lighting System Design

Published on October 20, 2013

Following items are helpful in selecting a proper luminaire: Utilization Factor, Photometric Data (Luminous Intensity Diagram & Zonal Luminous Flux Diagram) and Glare Data (Glare Quality Class & Glare Limitation Curves). y considering utilization factor along with its photometric data and glare data, complete design of a lightning system...

Read full article...

Carbon Trading

Published on October 13, 2013

Global warming is the increase in the average temperature of the Earth's near-surface air and the oceans since the mid-twentieth century and its projected continuation. Global surface temperature increased 0.74±0.18 °C during the 100 years ending in 2005. The Intergovernmental Pane...

Read full article...

Energy Scenario in India

Published on September 29, 2013

During the Eleventh five year plan (FY2007-12), nearly 55 000 MW was created against target of adding 78 700 MW. Before, in the Tenth plan period (FY02-07), capacity added was 21 100 MW against target of 41 100 MW. Additional 100 000 MW required by 2012 for which approximately ₹ 800 000 Cr. investment required...

Read full article...

Standards & Labeling

Published on September 22, 2013

Standards and Labeling has been identified as one of the key activities for energy efficiency improvements, for: having proven track record of being one of the most cost effective ways of reducing energy use; providing direct benefit...

Read full article...

Solar Energy

Published on September 15, 2013

India is a tropical country, where sunshine in greater intensity is available for longer hours per day. Annually about 5000 TW⋅h energy is incident over India's land area, with most parts receiving 4–7 kW⋅h∕m² on a typical day, with 250–300 sunny days in a year or 2300–3200 sunshine hours per year. The highest amount...

Read full article...

Maintenance of Fire System

Published on September 8, 2013

The fire detection, alarm and fire fighting equipment shall be kept in good working order at all times and maintenance schedule of the system should be drawn up by the maintenance unit and circulated to all the concerned for proper monitoring and execution. Fire safety officer shall be responsible for proper monitoring of the fire detection and fire fighting system and...

Read full article...

Fire Fighting

Published on September 1, 2013

As per IS 2190:2010, for all practical purposes, the basic types of fires can be grouped into following four classes: Class A fires, Class B fires, Class C fires and Class D fires. Class A fires are fires involving solid combustible material of organic nature such as wood, paper, rubber, plastics etc, where cooling effect of water is essential for extinguishment...

Read full article...

Fire Detection and Alarm System

Published on August 25, 2013

Prompt detection of an out-break of fire in its incipient stage and generation of alarm for quick and correct application of fire fighting media minimizes the loss from fire to a great extent. The purpose of a fire detection and alarm system is to detect a fire or its likelihood and generate audible and visual alarm to alert the building occupants...

Read full article...

Energy Audit

Published on August 18, 2013

Energy Conservation Act, 2001, defines Energy Audit as: “The verification, monitoring and analysis of use of energy including submission of technical report containing recommendations for improving energy efficiency with cost benefit analysis and an action plan to reduce energy...

Read full article...

Energy from Biomass

Published on August 11, 2013

Biomass is renewable, widely available, carbon-neutral and has the potential to provide significant productive employment in rural areas. Biomass is derived from numerous sources including by-product from sugar and wood industry, agricultural crops, forests etc. Biomass is an important source of energy and the most important fuel worldwide after coal, oil and natural gas...

Read full article...

Energy from Biogas

Published on August 4, 2013

Biogas is generated mainly from organic wastes such as cattle manure and other bio-degradable organic wastes through anaerobic digestion. The estimated potential of household biogas based plants based on animal wastes is 12 million...

Read full article...

Renewable Energy in India

Published on July 28, 2013

Renewable energy, is obtained from sources that are continuously replenished by natural processes. For example, solar energy, wind energy, bio-energy, hydropower...

Read full article...

Small Hydro Power

Published on July 21, 2013

Hydro power is one of the largest renewable energy resources being used for generation of electricity. SHP projects are classified based on capacity as follows...

Read full article...

Energy Recovery from Waste

Published on July 14, 2013

Increasing urbanization, industrialization and development activities result in generation of enourmous quantities of wastes in the urban and industrial areas. In India, each year about 30 Mt of municipal solid waste and about 4 400 million cubic meter of liquid waste are generated. Most wastes that are generated find their way into land and water bodies without proper treatment...

Read full article...

Wind Energy

Published on July 7, 2013

Wind energy has been in use in sailing and grinding and other mechanical applications for centuries. It has emerged as a viable renewable energy option with application in electricity generation, water pumping and battery charging. Generation of electricity has emerged as most...

Read full article...

Capacitors

Published on June 30, 2013

The All PP (APP) capacitors have been developed recently to overcome the limitations of metallized PP (MPP) capacitors. APP capacitors are already working very well in high voltage systems. These capacitors could not be introduced...

Read full article...

Power Factor Improvement

Published on June 23, 2013

Power factor is the ratio of the real power to apparent power and is either less than or equal to unity. In an AC circuit, current can either lag behind or lead to the voltage depending on the circuit elements and accordingly the power factor is termed as lagging or leading. Various causes can be attributed for low power factor...

Read full article...

Cables

Published on June 16, 2013

Selection of cable is based on the following factors: Current carrying capacity, Voltage drop...

Read full article...

Components of EA Set

Published on June 9, 2013

In telephone exchanges, the EA set is used for power requirement of essential loads like exchange load, pumps, lift, corridor and staircase lighting, FD and FF appliances and few essential lights on each floor. The main component of EA set are as follow...

Read full article...

Installation of Air Conditioning Plant

Published on June 2, 2013

A detailed programme for installation should be made and if the firm for carrying out the work is fixed, it should be discussed with him and targets finalized. This programme should at least decide dates for following events...

Read full article...

Factor Affecting Air Conditioning Plant Capacity

Published on May 26, 2013

Air conditioning is the simultaneous control of the temperature, humidity and pollution level within a limit of tolerance in a confined space. Such inside conditions may require to be maintained either for human comfort or for maintenance of equipment. The air conditioning load as such can be defined as that amount of heat which is instantaneously added or removed by the equipment. Heat flows from a hot medium to a colder medium and as such it is imperative that...

Read full article...

Air Conditioning Systems

Published on May 19, 2013

Air conditioning means the maintenaning the desired air conditions inside a confined space irrespective of outside atmospheric conditions. Air conditioning is basically provided to...

Read full article...

Servo Controlled Voltage Stabiliser

Published on May 12, 2013

The IE Rules 1956 stipulated that the supplier shall supply voltage at the commencement of supply limiting the variation to 6 % of the declared voltage in case of LV / MV distribution system and +6 % / -9 % in case of HV distribution system. But generally it is observed that very low voltage during the day & normal voltage during night in residential area and very low voltage during day and very high voltage during night in industrial areas. As most of the equipment are designed to operate for a voltage variation of...

Read full article...

IE Rules

Published on May 5, 2013

The Indian Electricity Rules, 1956 was made under section 37 of the Indian Electricity Act, 1910 (now repealed after enactment of the Electricity Act, 2003, but these rules themselves has been allowed to be in force till rules under section 53 of new Act are made). These Rules mainly deal with...

Read full article...

Stepper Motors

Published on January 13, 2013

Stepper motors operates on reluctance motor principle. The construction of these motors is quite simple. The stator has slotted structure equipped with two or more individual coils and rotor has salient projections but no coils. The rotor is designed with or without permanent magnet attached to its shaft and stepper motor is classified accordingly. If rotor has permanent magnet attached to its shaft, the motor is called permanent magnet stepper motor; otherwise it is called reluctance type stepper motor.

The input to the stator is in the form of pulses and on each pulse the rotor rotates in step by the desired angle. The angular shift per input pulse depends on the number of stator and rotor poles / projections. The train of pulses is generally...

Read full article...

Printed D.C. Motor

Published on January 6, 2013

Air gap is axial in such motors and the magnetic circuit completes through the ferromagnetic block at one end which also serves as the case of the ...

Read full article...

Tacho-generators

Published on December 30, 2012

Tacho-generators are used for measurement of angular velocity and give output voltage proportional to rotational speed. There are mainly two types of tacho-generators based on output voltage—d.c. tacho-generator and ...

Read full article...

Shaded Pole Induction Motors

Published on December 23, 2012

The shaded-pole induction motor usually has salient poles with one portion of each pole surrounded by a short-circuited turn of copper called a shading coil. Induced currents in the shading coil cause the flux in the shaded portion of the pole to lag the flux in other portion. The result is similiar to a rotating field moving in the direction from the unshaded to shaded portion of the pole causing induction of current in squirrel-cage rotor and a low starting torque is ...

Read full article...

Reluctance Motors

Published on December 16, 2012

The salient pole synchronous machine without any field or extiting winding runs at synchronous speed due to the reluctance torque and is termed Reluctance Motor. These motors find application in automatic control systems, telemetering devices and systems, signalisation circuits, sound film systems etc. requiring synchronised or simultaneous movements. Simplicity of construction is the main attraction of such motors. They are generally required in fractional kW sizes having ratings from a few watts to several hundreds of watts...

Read full article...

Rotating Amplifiers

Published on December 9, 2012

Power amplification may differ in magnitude with the variations in the value of ...

Read full article...

Servomotors

Published on December 2, 2012

In all servomechanisms, error signal is fed to an error-correcting device. This device then positions the output (valve, antenna, recorder pen etc.) so that it corresponds to the input. In order to do so, error-correcting device must be able to respond very quickly and have the ability to reverse direction. The most common device used in an error-correcting device is a servomotor. Servomotors can be either a.c. or d.c. While a.c. servomotors are used frequently, some applications require the use of d.c. servomotor

Read full article...

Selection of Pumps

Published on November 25, 2012

For selecting a pumping system, preliminary data should be carefully collected future increase in consumption of at least for next few years may also be considered. The following procedure is followed for selection of a pump...

Read full article...

Air Conditioning Load Estimation

Published on November 18, 2012

The actual instantaneous peak load requirement; type of control is determined by the condition to be maintained during peak and partial load. To estimate capacity of plant, an accurate survey of the load component of the space...

Read full article...

PAC Maintenance

Published on November 11, 2012

TROUBLE ANALYSIS FOR PACKAGE A.C. UNITS...

Read full article...

Window AC - Operation & Maintenance

Published on November 4, 2012

A typical refrigeration cycle for room air conditioners is shown in figure-I. Compressor takes in refrigerant vapour from the low pressure side, compresses it, and delivers it to the high pressure side of the system at higher temperature. In the condenser, discharged refrigerant...

Read full article...

Psychrometry

Published on October 28, 2012

Atmospheric air contains mostly a mixture of dry air and water vapour with some amount of other gases. Psychrometry deals with determination of thermodynamic properties of moist air and utilisation of these properties in analysis of conditions and processes...

Read full article...

Refrigerants

Published on October 21, 2012

A refrigerant should have low boiling point, its normal boiling point should be less than temp of refrigerant...

Read full article...

Scroll Compressors

Published on October 14, 2012

Scroll compressors offer high reliability, 100 % volumetric efficiency, low sound levels...

Read full article...

SMPS Power Plant

Published on October 7, 2012

The salient features & specification for SMPS based power plants are given in the table below. The figure of high frequency switched mode power supply is shown below...

Read full article...

Electrical Accidents

Published on September 30, 2012

The electrical equpments shall be installed such that they not only operate satisfactorily, but safely also. Every possible step should be taken to ensure safety and prevent accidents. The electrical accidents can be avoided...

Read full article...

Bus Bar

Published on September 23, 2012

Type of bus bars are open type and enclosed type. They are used...

Read full article...

Selection of Switchgear

Published on September 16, 2012

For selecting switchgears, in addition to normal factors current, voltage and frequency, the fault withstanding capacity is of prime importance. The allowable fault current depends on the capacity of supply company as well as the load and nature of fault. The fault level withstand capacity is known as rupturing capacity...

Read full article...

Constant Voltage Transformer

Published on September 9, 2012

These are basically servo stabilizers except for certain design aspects like very fast speed of correction and good normal and common mode noise suppression. Also they takes care of small dropout in the power for a few tens of milliseconds. They can be used for sophisticated electronic and electrical equipment like data processing equipments, elecro-medical equipments, electronic typewriters, telecom, VCR’s, PA systems, R&D labs etc. The typical specification for a CVT are given below...

Read full article...

Maintenance of Substation Equipment

Published on September 2, 2012

The switchgear and protective relaying system should be always alert to operate against an unexpectedly fault. Switchgear which was in quiescent state has to operate immediately. For such an operation, regular and detailed maintenance is necessary. The lack of maintenance may result in failure in operation...

Read full article...

Conductor Materials

Published on August 26, 2012

Specific gravity is the ratio of mass of any material to that of the same volume of water at 4oC. Density is the unit mass of material to that of volume at some reference temperature, usually 20oC. The numerical values, for all practical purposes, when density is expressed...

Read full article...

Instrument Transformers

Published on August 19, 2012

A transformer intended to supply measuring instruments, meters, relays and other similar apparatus is called an instrument transformer. These are, according to the quantity measured / monitored, further classified as...

Read full article...

Isolation Transformer

Published on August 12, 2012

Line transients and spikes are the main factors causing the wrong operation, erratic performance and inaccurate recording of the sensitive and sophisticated systems. Some of the effects of harmonics are...

Read full article...

Fire Protective Design of Buildings and Services

Published on August 5, 2012

State governments have enacted bylaws like Delhi Fire bylaws which are to be adhered to when constructing a high rise building. These bylaws have a statutory force. Designer must obtain and study the fire bylaws applicable to the particular area while planning. For the purpose of these regulations all buildings with height more than 15m are considered high rise buildings...

Read full article...

EA Maintenance

Published on July 29, 2012

Engine and alternator maintenance...

Read full article...

EA Capacity Selection

Published on July 22, 2012

For capacity calculation following procedure is applied...

Read full article...

Selection of Generating Set

Published on July 15, 2012

Selection of generating set has to be done either by weight, by speed or by operating cycle...

Read full article...

Remote Operation of EA Set

Published on July 8, 2012

The digitisation of information technology allows vast amount of data to share the same communication channel and thus remote monitoring of various electrical installation can be done from a distant station by digitizing the parameters and communicating them. This can result in a lot of savings as any major breakdown can be averted and also maintenance ond operator costs...

Read full article...

Space Requirement for EA set

Published on July 1, 2012

The various accessories and equipment associated with an EA set for which space is required are: EA set, control panel, batteries and exhaust pipe...

Read full article...

Noise Control for EA Set

Published on June 24, 2012

With the down trend in the construction of departmental bulidings and going for private accomodation that too in load centres the need for saving in space requirement and noise and poluution control has increased. Also there is increased awareness of noise and pollution and these are to be kept under...

Read full article...

Generating Set Ventilation

Published on June 17, 2012

Air flow requirement of generating sets

Read full article...

Protection of Buildings against Lightning

Published on June 10, 2012

Protection of special structures, such as those exceeding 30 m in height, structures with roofs of high inflammability, buildings with explosive or highly inflammable contents, fences, trees and structures near the trees, structures supporting overhead electricity supply, telephone and other lines, structures with radio and television aerials, tents, metal scaffoldings and similar structures, tall metal masts, tower cranes and revolving and travelling structures, farm buildings in area of high lightning incidence, sports stadium, raised motorways, bridges, dwelling houses etc is done...

Read full article...

Lightning Mechanism

Published on June 3, 2012

Storm fronts are caused by the rising masses of warm air which expands at attitudes of upto 15 000 meters. At the centre, at about 6 000 meters, there is a powerful up draught, leading to the separation of charges. The presence of ice crystals and supercooled water droplets is closely associated with this formation of electric fields by separation of charges. Studies has demnstrated that hailstones bear negative charges and ice crystals bear positive charges. Being lighter, the ice crystals are carried by the up draught into the upper region of the cloud, whilst the hailstones fall into central regions of the cloud. So by this process, positive charges gets accumulated in the upper part and negative charges in the lower part...

Read full article...

Surges

Published on May 27, 2012

AC equipments are subjected to occasional lightning surges, switching surges and power frequency overvoltages. Upto voltage levels of 345 kV lightning surges are more dangerous and after that switching surges which are consided to be 2.7 p.u. wheareas lightning level is around 900 kV. Each equipment has certain assigned withstand levels as...

Read full article...

Lightning Arrester

Published on May 20, 2012

Requirements of a protective device: It should take no current during normal power frequency condition. The breakdown strength should be above the normal power frequency voltages and permissible over voltages (normally 5 to 10 %). Transient over voltages of value more than insulation flash over should be diverted...

Read full article...

Motors and their Protection

Published on May 13, 2012

The performance of a motors with various ratings vary as follows: slip varies directly as the output; starting torque and starting current vary inversely with the output. Frequent starting, reversing or heavy starting conditions may necessiate selection of a motor with an output rating higher than that normally required for continuous duty. The normal design criterion is that the motor shall be capable of two starts in succession at rated load torque, inertia and temperature, followed by a cooling period of 30 minutes before attempting a further starting sequence. At rated voltage, the motor can withstand 1.25 to 1.5 times the rated current for two minutes without suffering damage or permanent deformations...

Read full article...

Power Transmission by Vee Belt drives

Published on May 6, 2012

The polyster cords are replacing the conventional rayon cords as reinforcement members of industrial V-belt drives due to their higher power transmission capacity, lower belt stretch and higher dimensional stability. Another development in V-belt technology is the polychloropre (Neoprene, Bayprene etc) covering given to the base rubber belt. This jacket offers improved oil, heat and water resistance. The following is the typical data about polyster cord reinforced V-belts...

Read full article...

Power Transmission by Flexible Coupling

Published on April 29, 2012

The flexible couplings allow certain amount of parallel and angular misalignments and absorbs shock forces and hence they are preferred for many direct drives. The resilient tyre flexible coupling finds wide acceptance due to their desirable features of easy installation and maintenance. The details required for selection of coupling are...

Read full article...

Lift Operation

Published on April 22, 2012

The various controls like governing, starting, stopping, direction of motion, acceleration, speed and retardation are specified in IS 1860 : 1968. The generally used controls are given below...

Read full article...

Selection of Lift

Published on April 15, 2012

For selection of a passenger lift, following factors are considered: quality and quantity of service. Quantity of service is a measure of passenger carrying capacity during 5 minutes peak period of day and is also known as passenger handling capacity...

Read full article...

Installation of Lifts

Published on April 8, 2012

The important points which should be seen for satisfactory installation are: The working drawing showing the lift shaft and machine room details should be forwarded to the firm for the preparation of general arrangement drawing. The existing site dimensions of lift shaft, pit and machine room (if constructed ) should also be...

Read full article...

Features of Luminaires

Published on March 25, 2012

The quality of a finished product depends on the quality of raw materials used, workmanship and the manufacturing processes adopted. The main features of the luminaires should be: The luminaire should be efficient and be able to do its function of light distribution etc effectively, these properties depend upon the raw material used and the treatment and finishing done...

Read full article...

Uninterrupted Power Supply

Published on March 18, 2012

This is the era of information technology and so many sophisticated devices like PCs are used which are very sensitive to the supplies having spikes, power glitches, electrical noise, voltage sags and surges, waveform distortions, frequency variations and brown outs. The Computers needs clean and uninterrupted power. The most sensitive device of a computer is the disk drive which is driven by a motor whose speed depends upon the frequency. Thus frequency variation can cause reading errors, dropping or addition of a few bits...

Read full article...

Earthing

Published on March 11, 2012

Though electrical equipment are manufactured and installed to give trouble free service, failure of various components cannot be ruled out. Failure of electrical equipment or system happens due to: Insulation puncture, accidental contact between low & high voltage line, break-down of insulation between primary and secondary of a transformer and lightning strokes. These may cause...

Read full article...

EI Design

Published on March 4, 2012

The aspects for the design are energy conservation, flexibility, aesthetics and user friendliness. Appreciation of these factors will help in a systematic approach. Besides these items of general nature there are certain specific requirements also of a particular building / space which need to be taken into consideration while finalizing the design. Giving regard to general and specific requirements certain recommendations are made for each type of building and for each of the spaces constituting the building...

Read full article...

Aviation Obstruction Light

Published on February 26, 2012

High-rise buildings and structures such as chimneys, towers and smoke stacks are potential hazards to aircraft. As such mandatory provisions are in force for providing AOL's for hazard indication on structures above 6m in height...

Read full article...

Task Lighting

Published on February 19, 2012

When a general lighting proves inadequate for a specific task it is necessary to provide a licalised light in order to obtain the required type and degree of illumination. This can be grouped in four types...

Read full article...

Nuclear Energy

Published on February 12, 2012

France's 80 % of electricity is generated by 58 nuclear power plants. Nuclear production of electricity is steady and consistent while wind turbines (even at their best) generate power only 22 % of the time. Solar cells do not work in bad weather or darkness. Backup systems running on fossil fuels must keep running on standby so all the advantages of reduced emission are lost...

Read full article...

Estimation of Air Conditioning Work

Published on February 5, 2012

In order to procure and install package type air conditioning system, it is essential to have the details of various items of work involved and their quantities. To have the above information in consolidated form...

Read full article...

Design Conditions for Air Conditioning

Published on January 29, 2012

Design conditions to be maintained...

Read full article...

AC Ducting

Published on January 22, 2012

Factors affecting ducting: Shortest path to reduce power, material and space...

Read full article...

Synchros

Published on January 15, 2012

Synchros are a.c. electromagnetic devices that find wide application in servomechanism. However they can also be used as indicating instruments for registering mechanical displacements remotely.

There are four basic types of synchros—control transmitter (CX), control transformer (CT), control differential (CD), and control receiver (CR) ...

Read full article...

Magnetic Amplifiers

Published on January 8, 2012

Magnetic amplifiers utilize the concept of magnetic saturation. The heart of the magnetic amplifier is the saturated core reactor. When a saturated reactor is used in a circuit to amplify, the entire circuit becomes a magnetic amplifier...

Read full article...

Geothermal Energy

Published on January 1, 2012

Geothermal energy is an energy which is obtained from Earth. It is a pollution free source of energy and can be used continually. In the core of Earth, many radioactive materials like magma, uranium and thorium are found in abundance. As per the scientists, these can be sources...

Read full article...