Posted by: SATYASRINIVAS | February 11, 2016

Selecting FO patch panel,Pigtail,Patch Chord Components

You need to have the following prior information;

Type of FO cable: Single Mode OS1/OS2;
Multi Mode: OM1/OM2/OM3/OM4;
Netowork is Simplex/Half Duplex/Full Duplex;
For Simplex network One core of FO cable will be enough;
for Duplex netowkr: Minimum 2 Core’s FO cable is required.
Single Mode Pigtail:
Pigtail will have connector at One end only.
Type of FO for pigtail shall be same as that of Network FO cable:
If main FO cable is Single OS2 then Your Pigtail shall also be OS1 Pigtail with connectors being typically SC/LC;
If your network is Simplex: SC/LC Connector will be Simplex;
If Your network is Duplex: SC/LC Connector will be Duplex;

FO Patch Chord Selection:

FO patch Chord will connector at both ends (in contrast with the pigtails which has only one end Connecotr)
Further to the above, You need to check your Media Convertor Port/ Ethernet Switch FO Port Type;

If the Network switch Port is SC Duplex type then FO patch one end Connector shall be SC Duplex Connector and other end will depend on the Pigtail connector selected.

If Pigtail Connector is LC Duplex then better to patch chord second end shall be LC duplex type;

Selection FO Patch panel:
You need to specify the no of Fiber Port and Adapter specifications;
Typical Adapter specifications will be:
SC-SC Duplex Single Mode OS2 Adapter;
SC-LC Duplex Single Mode OS2 Adapter;
No of adapter required shall also be mentioned in your enquiry to supplier;

1 SC-SC Duplex Adapter would occupy Two Port/Slots of patch Panel where as 1 LC-LC Duplex Adapter will occupy One Port/Slot of Patch panel.

With8 SC-SC Duplex Adapter will have 16 Slot FO patch panel and you will be able to connect 16 cores of FO cable;
where as 8 LC-LC Duplex adapter will have 8 Slots of FO patch Panel, but still you will be able to connect 16 Cores of FO cable.

This is because LC-LC Duplex adapter is half the size of SC-SC Duplex adapter.
So care must be taken while specifying the no of FO ports of patch panel.

Posted by: SATYASRINIVAS | February 11, 2016

Selection of Ethernet Switches

Posted by: SATYASRINIVAS | February 11, 2016

Selection of FO cable for 1 GBPS network

care Mustbe taken while selecting FO Cable for 1 Gbps Network.

FO Cable has major classification of : OS1/OS2 for Single Mode and
OM1/OM2/OM3 & OM4 for Multi Mode;

Care must be taken while choosing the Type of OF Cable mainly based on the Distance they will support w.r.t the 1Gbps/100Mbps Network your designing;

Once your know the distance and Network speed: The you can select the type of FO Cable based on the following wiki article.

Posted by: SATYASRINIVAS | February 11, 2016

Fiber Optic cable Design & Costing

Unitube vs Multi Tube;
FRP Armoured and Armoured thickness;

Type of Constuction:

Whether Single Tube armoured cbale/Multi Tube single sheath Armoured;
Multi Tube double sheath armoured/Multi tube steel wire armoured/Multi Tube FRP Rod Amrmored;

Cheapest is Single Tube armoured cable;
costliest is Multi tube FRP Rod armoured;

For construction details Refer:

Posted by: SATYASRINIVAS | January 21, 2015

Standard Phases for professional E-mails/Letters

Dear Mr/Mrs xxxxxx,;

With reference to our telephone conversation today, I am writing to confirm….;

Please find enclosed a copy of the proforma invoice for this order ;

We would be grateful if you could make payment as soon as possible;

Should you have any questions, please do not hesitate to contact us;

Thanks for your understanding.

Yours sincerely (British English)

Sincerely yours  (American English)

Yours faithfully (if you don’t know the name of the person you’re writing to).

Best Regards/Regards  (In mails to your colleagues at-par/Sub-ordinates in allocating works )

Thanks & Regards ( In mail to your immediate in charge and also to show more courtesy towards colleagues & Sub-ordinates when they do a favor or complete the assigned job )

Better to write Dear Mr Sir Name instead of writing Dear Mr. Full Name

Hope the above time is convenient  for you to discuss all the points related to Raaxha Project.

Request for information

I am writing to inquire about . . .
I am writing in reference to . . .
I read/heard . . . and would like to know . . .
Could you please send me . . .
at the address below/above
Thank you for your assistance.
I look forward to hearing from you.

Response to request
Thank you for your interest/inquiry
Enclosed is the information you requested.
You can learn more about this at . . .
If you have further questions,
If you require assistance, please contact:
If I can be of more help, please feel free to contact me at . . .

Sample Sentences: Requests
Could you please send me your most recent brochure?
Could you fax me the results of the market survey?
I would like to order ten copies of the book, Touchy Situations.
I would be very grateful if you could send me this information.
Please return the enclosed envelope with your payment.

Sample Sentences: Goodwill
Thank you for your hospitality.
I enjoyed having lunch with you last week while I was in New York.
Congratulations on your promotion to General Manager.
I want(ed) to congratulate you on your new position.
I was happy to hear that contract negotiations went well.
Sample Sentences: Introduction of Product/Service
I am writing to tell you about . . .
(Our new product) is coming out next month.
This product/service is designed to (help you) . . .
Sample Sentences: Reference
I am writing in regard to . . .
I am writing in reference to . . .
Please refer to the enclosed invoice/brochure.
I hope you have had a chance to look over the materials we sent

Sample Sentences: Confirmation
I am writing to confirm . . .
I would like to confirm what we discussed last Friday.
I would just like to confirm the main points we discussed . . .

Sample Sentences: Notification
I am writing to let you know that . . .
Please be aware / informed that . . .
I would like to inform you of a recent policy change. I am happy to inform
you that . . .
Your request for funding has been approved.
Sample Sentences: Offering Assistance
We would be happy to . . .
If we can be of assistance, please don’t hesitate to ask.
Sample Sentences: Collection
According to our records . . .
Our records show that . . .
Your monthly installment is past due.
Please send payment as soon as possible.

Addition References;Formal Letters_6

IRIG refers to the Inter-range Instrumentation Group.

The ‘formats’ of IRIG time codes are many, but the 3 most common formats are IRIG-B ( with significant share of the market), IRIG-A (Minimal market share), and IRIG-G (very little marker share).

IRIG time code signals may be:
(a) Unmodulated (DC level shift, no carrier signal)
(b) Modulated (amplitude-modulated, sine wave carrier).
(c) Modified Manchester (amplitude-modulated, square wave carrier).

The above with reference to IRIG-B application

(a) IRIG-B (TTL/DCLS): It is more common with New IED’s. It offers better resolution than IRIG-B AM But but cannot be used in runs of more than 100m (unless you use repeaters or optical outputs)

(b) IRIG-B AM: It is more common with older IED’s. Comapred with TTL case It is less accurate, But it can be run further than above. AM IRIG-B signals generally use coaxial cables, and most commonly BNC connectors. However, use of BNC connectors does not guarantee that it is an AM IRIG-B signal being used

IRIG-B AM is generally used in a larger power plant with master and slave clock system. With slave clock’s and BOP/Off-site PLC’s typically located more than 100m from DCS Room.

(c) Rarely used. Hence not discussed.

In summary “IRIG-B” alone does not adequately define protocol or electrical requirements. Specify AM IRIG-B or DCLS IRIG-B (or the full IRIG-B code) to be more specific. To be helpful, also specify the electrical requirements (desired voltage level) of the IED and to be really helpful, specify the connector type at the IED (BNC, screw terminal, DB9 etc).

For Detailed Information on IRIG-B kindly go to the refer this Technical Note.

Phasor Diagram:

The two alternators are running in parallel with their excitations constant. The armature currents I1 and I2 are also equal so that total load current is 2I1 or 2I2. The terminal voltage V is constant. Each alternator is sharing a load equal to P

Now when mechanical torque of alternator 1 is increased, its output will also increase. But E1 (Induced E.M.F), V and Xs are constant. So to increase power angle must be increased from δ to δ1 so new Ewill be ahead of previous position. The alternator 1 shares greater load than P. Therefore for constant load of 2P the load on alternator 2 must be less than P. This will make new E2 to fall back from its previous position. Due to the different positions of Eand E2, resulting voltage AB appears in the local circuit which will send a circulating current ISY lagging behind the voltage by 90o. This current ISY must be added to I1 and subtracted from I2.
The alternator 1 carries increased current I’1    (Note the Angle between V and I’ is Φ1  . This is why there is change in Power factor) and alternator 2 carries decreased current I’but total load current remains same  (Ī = Ī’1 + Ī’2). The power factor of alternator 1 is improved from cosΦ to cosΦ1 whereas it is reduced from cosΦ to cosΦfor alternator 2. But the load power factor remains unaffected.
Thus increase in mechanical torque in case of alternator will increase armature current and improve the power factor. The alternator will share increased load whose driving torque is increased whereas the other alternator which is in parallel is relieved from the load whereas the reactive power distribution remains unaffected.
     To consider the effect of change in input on corresponding power triangles of the two alternators we will assume that the two alternators are turbo alternators whose prime mover are supplied with steam.
       Now the excitations for the two alternators are kept constant where steam supply i.e. power input to prime mover of alternator 1 is increased. The two alternators are running in synchronism. So machine 1 cannot overrun machine 2. The increased power input for alternator 1 makes it possible for carrying more load. This will make rotor fort machine 1 advancing its angular position by an angle δ.
       The resultant e.m.f. Er is produced in the local circuit which will setup a circulating current ISY which lags Eby 90and almost in phase with E1. The power per phase fort alternator 1 is increased by an amount E1ISY whereas it is decreased by same amount for alternator 2. This current ISY has no appreciable reactive component and it will not disturb the reactive power distribution but active power output of alternator 1 will increase and that of 2 will decrease.
Posted by: SATYASRINIVAS | January 11, 2014

250 kW Biomass Gasification based Power Plant

What is Biomass and Biomass fuel?

Biomass fuels are organic materials from living plants and animal waste. They


·   Wood and wood residues such as sawdust, wood pieces etc.

·   Crop residues such as straw from grains, rice husks, sugarcane etc.

·   Residues from livestock production such as excreta, slaughterhouse residues, 


In this 250 kW power plant project, rice husk is used as biomass fuel.

Biomass gasification technology

Biomass gasification is viewed today an alternative to conventional fuel. Biomass gasification is the process of converting solid fuels (rice husk, wood/ wood-waste, agricultural residues etc.) into a combustible gas mixture usually called the “Producer Gas” i.e. biomass materials are gasified to produce “Producer Gas”. The technology can be used for both thermal applications and power generation.

The advantages of gasification are:

·         It ensures efficient usage of traditional biomass products by converting it into a high quality, combustible gaseous fuel.

·         Biomass gasification technology is environment friendly which significantly reduces environmental pollution caused by traditional usage of biomass products.

·         Reasonable cost of energy/ power production to operate as a commercially viable entity.

Biomass is a renewable source and its application as a fuel does not result in net CO2 emission because the CO2 released during the conversion of biomass is equivalent to that which has been absorbed by the biomass from the atmosphere. Thus, unlike fossil based fuels, it is a CO2 neutral energy source.

Biomass gasification technology: Power Generation

For Power generation, biomass gasification process consists of 3 major components:

  1. Gasifier unit

  2. Gas purification unit

  3. Internal Combustion (IC) Engine

At first, rice husk is fed into the gasifier and gas is produced inside the gasifier. Produced gas is then cooled and cleaned in the purification unit and finally clean gas is fed into the engine to generate power.

1.   Gasifier unit

The gasifier is essentially a chemical reactor where various complex physical and chemical processes take place i.e. drying of fuel, pyrolysis, combustion and reduction. There are mainly two types of gasifier: 1. Updraft 2. Downdraft. In updraft technology, the produced gas is drawn from the top of the gasifier while in down draft technology; the gas is drawn from the bottom of the gasifier. In this project downdraft technology is used. Biomass is fed into gasifier at specified intervals. Biomass is burnt inside of gasifier and gas is produced which is known as “Producer gas.” The equipment is designed in such a manner that it takes in air in controlled quantities, resulting in partial oxidation of biomass. One kg of biomass can produce 2.5 to 3.0 Nm3 of producer gas with a calorific value of 1000-1300 Kcal per Nm3. Specifications of the gasifier used in this project given below:



Gasifier Type



Total 250 kW

Rated Gas Flow

625 Nm3 /hr (up to total 250 kW capacity)

Average Gas calorific value

> 1,050 (Kcal/Nm3)

Rated Biomass consumption

Up to 300 kg/hr (for total 250 kW capacity)

Gasification Temperature


Gasification Efficiency

Up to 75%

Temperature of Gas at Gasifier Outlet

250 to 400oC

 Biomass Feeding


Desired Operation

Continuous (minimum 300 days/yr)

Typical Auxiliary Power Consumption

Up to 11 kW

Typical Gas composition

CO-20.62%, H2-10.62%, CO2-13.61%, CH4– Up to 4%, N2-52.62%

2. Gas purification unit

The gas coming out of the gasifier has a temperature of 450oC or higher. The hot gas generally contains tar and fine particles of ash, which need to be cleaned before feeding to the engine. Since this project uses downdraft technology, therefore gas cleaning and cooling system is less complicated and easy for maintenance. Following gas purification stages and filter element have been used in each stage of this rice husk based power plant:

Stage 1: Coarse Filter: uses rice husk char as filter element to partly clean the gas

Stage 2: Fine Filters: sawdust is used as filter element to trap all the particulate and ash particles

Stage 3: Safety Filter (‘SF’): a special kind of fabric (rated for 5 micron particulate size) is used as filter element

3. Internal Combustion (IC) Engine: Duel-fuel Engine

In this project, a 300 kW capacity duel-fuel generator is used to generate electricity. Mainly the gas that has been produced by the gasification of biomass, generates electricity. However, in this rice husk based power plant, to run the generator certain amount of diesel is required. Because, the producer gas has relatively lower heating value and needs to be supplemented by diesel to get the necessary power output. That’s why the IC engine has been converted into duel fuel mode, i.e. it can run both on producer gas and diesel. Using this technology Producer gas to diesel ratio is. 70:30. During start up of the plant, main generator is started first on diesel and then changed over to duel fuel mode when the producer gas is available for charging to the engine.

Power distribution Network

A mini grid has been constructed to sell the power to the adjacent area. The plant is able to deliver power at least 200 households and over 100 commercial entities of that area.

Environmental impact

Generally 4 types of effluent are generated from the gasification process like ash, char, tar, and waste water. Ash is collected in wet condition. Around 20% of rice husk is made up of ash and the ash coming from the gasifier contains 10 to 15% carbon by weight. The ash-laden water can be used as organic fertilizer or land filling purpose. The plant has on site storage facility for ash. Char can be transformed into charcoal which is used as a domestic fuel for cooking and heating. Tar can be either recycled or burnt in the gasifier or used as black paint for the wooden materials like boat, wooden structures and construction of roads. In case of a downdraft gasifier, there will be little liquid emission from the plant. The plant has onsite storage facility to deposit waste water which needs to be changed in every three month.


Source : Renewable Energy Information Network, Bangladesh

Posted by: SATYASRINIVAS | September 14, 2013

how to stop receiving airtel flash message

  I recently bought an Airtel sim. I am getting flash messages on the screen continuously. To stop this, We  can do the following steps.

Step1: Go to Airtel Live! (In my sony mobile: It is in Enetertainment  ICON)

Step2: Click on Airtel Now

Step3: Click on Start/Stop

Step4: Click on Stop

Posted by: SATYASRINIVAS | September 9, 2013

Life is like a cup of coffee

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