Posted: 28 Dec 2010 10:45 PM PST

Hello friends,

Just logged in to tell you that my PC mouse has been broken. Therefore I am here to get some advice to buy a new wireless mouse. I am clueless that where should I visit to buy a new wireless mouse. Please suggest me any website where I can checkout and purchase latest and good quality wireless mouse.

Posted: 28 Dec 2010 08:36 AM PST

Why Hydrogen Gas is the best cooling medium for rotating machines?

Utilization of Hydrogen gas as the cooling medium either for inner-cooled or for conventional type hydrogen cooled units has the following advantages:

1) Hydrogen gas is small in density; therefore decrease windage and ventilation loss.
2) Hydrogen gas has large thermal conductivity and surface heat transfer coefficient, Therefore, the output per unit volume of active material will increase and the limit of maximum practical rating can be made larger than with an air-cooled unit.
3) Freedom from oxygen and moisture results in little corona effect, thereby prolonging the insulation life of the stator coil.
4) Small gas density and closed ventilating system will reduce noise.
5) Hydrogen-cooled machine is convenient for converting into an outdoor type.

-Common gases which are much lighter than air are (hydrogen and helium). Although helium is inert non-flammable, and an ideal medium for ventilating purposes, it cannot be obtained in quantities, which makes its price high and makes it unsuitable as cooling medium,
-On the contrary, hydrogen can be obtained rather inexpensively, and it has advantages over helium in having a small density and better thermal characteristics.

SFETY NOTE.
-The intensity of explosion of an air-hydrogen mixture varies with the proportion of the two gases present, and also has to do with the gas pressure.
-A curve on which the values of intensity are plotted against the properties of gases will be approximately a sine wave having zero values at (4 % and 75 % hydrogen), and reaching a maximum intensity in between.
-So we have to take care:-
*Hydrogen and air should never be mixed.
*Carbon dioxide should be used as an intermediate gas when changing air to hydrogen, or from hydrogen to air.
*When charging gas, provide vent to the atmosphere from generator.

Project based on Computer Networks

Posted: 28 Dec 2010 08:29 AM PST

Hi all.
Am a student of Electronics and Telecomm Engg,3rd yr.
I need some tips from you guys regarding what I can pursue as my major project.
I don't want it to be even near to robotics(no mechanical engg involvement).Also it shouldn't be completely based on Microcontroller.!
Can I make a project based on Networking(WWW or any cellular network based.)
Also it should have features that makes it an Electronics project,like i can interface lcd with microncontroller for display n so on.
I mean it shouldnt seem like a total CS project.
Can you guys suggest me some project based on Networking.Am ready to learn and work at any level of programming and we have around one full year time for the completion of the project.

The right way to wire an electronic ballast to T9 tube

Posted: 28 Dec 2010 06:56 AM PST

I would like to draw your attention to an illustration linked to an old post on this forum entitled "Circuit diagram of tube light/ December 2008":

I have purchased a draughtsman's lamp from the USA last year since it was the only fluorescent/ incandescent combination lamp I could find on the internet. I had to operate it using a 240V to 110V step-down transformer, which was an economical concern from the onset, so I attempted to convert the lamp to the British 240V convention and replace the inductance ballast with an electronic ballast. I rewired the incandescent lamp by adding an L pole from the mains. The whole rig works fine, if not for a little bit of unconventional wiring for the tube light.

The original lamp's circuit has a conventional inductance ballast and starter identical to the second diagram in the illustration above.

My lamp's ballast lives in the base of the lamp with the N wire and the ballasted L wire fed through the swing arm stem to the lamp housing, i.e. only two wires, in stead of four, which appears to be the proper way to wire an electronic ballast to the tube viz. illustration above.

I have removed the inductance ballast and replaced it with an OSRAM Quicktronic ECO electronic ballast. Having played around with the contacts on the ballast I managed by chance to find an unconventional way to power the lamp without the use of the starter condenser and without adding more wires to the lamp housing. This was achieved by jumping S1 to S3 and jumping S2 to S4 as in the diagram. The FS-22 starter is removed:

I am not currently using the lamp with this configuration, and I'm not professing such a use. I would like to draw your attention to the fact that the circuit does work, though. Can anyone shed some light on the function of the electronic ballast and how the electricity is conveyed to the tube. How does the lamp ignite and retain luminescence with an apparently broken circuit? I also need some advice as to how safe this configuration is and weather such a configuration may shorten the life of either the ballast or the lamp.

Crazy Engineers .CoM

Wednesday, December 29, 2010

CrazyEngineers Forum - Electrical & Electronics Engineering

CrazyEngineers Forum - Electrical & Electronics Engineering

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