How a nuclear reactor makes electricity

 A nuclear reactor produces and controls the release of energy from splitting the atoms of uranium.

Uranium-fuelled nuclear power is a clean and efficient way of boiling water to make steam which drives turbine generators. Except for the reactor itself, a nuclear power station works like most coal or gas-fired power stations.

The Reactor Core

Several hundred fuel assemblies containing thousands of small pellets of ceramic uranium oxide fuel make up the core of a reactor.  For a reactor with an output of 1000 megawatts (MWe), the core would contain about 75 tonnes of enriched uranium.

In the reactor core the U-235 isotope fissions or splits, producing a lot of heat in a continuous process called a chain reaction.  The process depends on the presence of a moderator such as water or graphite, and is fully controlled.

The moderator slows down the neutrons produced by fission of the uranium nuclei so that they go on to produce more fissions.

Some of the U-238 in the reactor core is turned into plutonium and about half of this is also fissioned similarly, providing about one third of the reactor's energy output.

The fission products remain in the ceramic fuel and undergo radioactive decay, releasing a bit more heat.  They are the main wastes from the process.

The reactor core sits inside a steel pressure vessel, so that water around it remains liquid even at the operating temperature of over 320°C.  Steam is formed either above the reactor core or in separate pressure vessels, and this drives the turbine to produce electricity.  The steam is then condensed and the water recycled.

PWRs and BWRs

The main design is the pressurised water reactor (PWR) which has water in its primary cooling/heat transfer circuit, and generates steam in a secondary circuit.  The less popular boiling water reactor (BWR) makes steam in the primary circuit above the reactor core, though it is still under considerable pressure.  Both types use water as both coolant and moderator, to slow neutrons.

The main design is the pressurised water reactor (PWR) which has water in its primary cooling/heat transfer circuit, and generates steam in a secondary circuit.  The less popular boiling water reactor (BWR) makes steam in the primary circuit above the reactor core, though it is still under considerable pressure.  Both types use water as both coolant and moderator, to slow neutrons.

Natural Prehistoric Reactors

The world's first nuclear reactors operated naturally in a uranium deposit about two billion years ago in what is now Gabon. These were in rich uranium orebodies in the Earth's crust and moderated by percolating rainwater. (At that time the uranium-235 isotope was more concentrated than it is today.)

Nuclear energy's contribution to global electricity supply

Nuclear energy supplies some 12% of the world's electricity. Today 31 countries use nuclear energy to generate up to three quarters of their electricity, and a substantial number of these depend on it for one-quarter to one-third of their supply. Over 15,000 reactor-years of operational experience have been accumulated since the 1950s by the world's 440 nuclear power reactors (and nuclear reactors powering naval vessels have clocked up a similar amount).

Water Level Indicator with Alarm System

This is a simple and very useful circuit to check the water level in a container or a Tank. It gives visual indication at three levels and when the tank is about to overflow then it gives audio alarm. This is a very economical and easy to build project. But please take the help of adults if you are not familiar with soldering iron.

Required Things

Required Tools

Circuit Diagram

Construction and Description:

Paint the rectangular wooden base of the size 8 inches x 6 inches with acrylic color.

If you are not familiar with soldering technique then ask an adult or go to your nearest electronics shop and ask them to assemble the circuit on general purpose board (according to the circuit diagram).

Fix the plastic container on the wooden base (as shown in the picture above).

Fix the battery, buzzer and assembled board on the wooden base with the help of Foam Tape.

Make a probe of an insulating material such as plastic (you can use empty sheel of pen) as shown but ensure that its length is more than the height plastic container.

Put the probe vertically inside the empty plastic container.

Now attach the battery clip to the battery and start filling the water in the container.

As the water crosses each level of the probe in the container, you will notice the corresponding visual indication on the circuit. And in the last level alarm will sound.

After Whole Assembly 

How to Compensate Power Factor in 5 ways

Power Factor Improving Methods
1-Individual (fixed) Compensation
2-Group Compensation
3-Centralize Compensation
4-Dynamic PFC
5-Active Harmonic Filter

Electric Machinery Fundamentals 5th Edition By Chapman

Electric Machinery
Fundamentals
5th Edition
By Chapman

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What is Inside A Car Engine and how it Works basic information about engines

HOW THE PARTS COMBINE

Most vehicles operate on three or more cylinders and for the four-stroke process to work, at least two cylinders must be used. Cylinders work in cycles so that each will be on a different, though complementary, stroke from the others. In a four cylinder engine (one of  the most common in automotive), for example, the first cylinder may be operating on the Intake Stroke as the second is under Compression, the third producing Power, and the fourth Exhausting. Thus, one cylinder is producing power while the others are going through their strokes to do the same down the line, each in turn.

Typical engine configurations are “flat” four-cylinder, an inline, and V. Each operates the same way, but has a different camshaft configuration and harmonic balance. Similarly, an engine’s output is measured in four ways: RPM, torque, horsepower, and fuel efficiency. RPM is simply rotations per minute – the number of times the crankshaft is turning a full rotation in one minute. An engine operating at 3,000 RPM, for example, is turning it’s crankshaft 50 times per second. Torque is a physical measurement of the amount of actual power turning the crankshaft. Horsepower is a power measurement used to illustrate the amount of work the engine is doing. Fuel efficiency is a measurement of the amount of fuel required to do a certain amount of work with the vehicle (such as propel it to or sustain speeds of 55 mph).

Digital Fundamentals 9th Edition By Floyed

Digital Fundamentals
 9th Edition
 By Floyed

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How to Find Apmeres Drawn by Electric Motors according to size ?

Amp draw is a measurement of the power being consumed by a blower motor to move the air through your HVAC system. It’s one of the lesser-used diagnostic tests, but perhaps if we focus on how to measure amp draw and learn to better interpret what it can tell us, we will expand our ability to provide comfort to those we serve.

To interpret the meaning of an amp draw reading, you need to know the capacity of the blower motor that’s turning the fan. This is found in the nameplate of the motor and is called “full load amps,” designated by the initials FLA.

When a motor operates at 100% of its FLA, it’s operating at 100% of its capacity. The goal of the test I’ll present here is to compare the measured amps that the motor is using to the FLA capacity of the motor.

When a system has been renovated and system performance has been maximized, it’s common to read amp draw at 80% to 90% of FLA on a most direct-drive residential units.

If the measured amp draw exceeds the capacity of the motor, the motor will fail prematurely. Excessive heat is what usually causes damage to a motor, and when a motor is working beyond its FLA, its life expectancy is decreased significantly.

If the measured amp draw is only half of the FLA, the chances are that you have a serious air flow problem that will require additional work to get the system to perform properly.

Test Instruments

Most of us carry one of many electrical multimeters that are on the market to test electrical properties. On these meters, there is a selection for AC Amperage that allows for a wide range of testing sufficient for all sizes of residential blower motors. An electrical meter will range in cost from $60 to $500. As with all tools, you get what you pay for.

Some meters come with a built in AC current clip that looks like two fingers at one end of the meter that wrap around the wire being tested.

To measure ampacity on most smaller systems, you clamp onto a wire in the blower compartment, then close the blower compartment door during the test.

To get access into the blower compartment requires a remote amp clamp attached to the end of a 3-ft. to 4-ft. cord. The amp clamps look like a clothespin with two insulated wires that attach it to the meter. This clamp snaps onto the power lead of the motor and measures the flow of the current pulled by the motor.

Remember to have your test instruments calibrated annually so that you can have trust and confidence with your readings and diagnostics.

First, Safety

Before we discuss taking measurements, let’s look at safety. This amperage measurement is taken with the power on and a fan that often moves from 500 to 2,000 rpm. With some systems you may have fingers and test leads dangerously close to this moving fan.

Also, whenever you’re measuring electricity, whether this is a new test for you or if you’ve successfully performed it a thousand times, please pay attention to your personal safety.

Here’s my favorite safety quote: Whenever taking electrical measurements, or working with fans and pulleys, remember that even a fleeting misunderstanding or inattention to energized equipment may easily carry the punishment of death, enforced promptly, without the chance of appeal anywhere on Earth.

No diagnostic measurement is worth a finger.

Should you ever be tempted to reach in and pull out a wire to test with your bare fingers, be aware that insulation may have been stripped from the wires and you could be headed for some serious pain, or even the punishment mentioned above.

Having said that, let's take a look at how to measure amp draw of a residential direct drive blower. Even if you often deal with large commercial systems, read on, the same principles apply.

The Test Procedure

1. Disconnect power from the blower motor by shutting it off at the disconnect box to the unit or unplugging the power source.

2. Open up the blower compartment of the furnace or air handler. Find the Full Load Amp (FLA) rating of the blower motor. If the motor is direct-drive these numbers can be difficult to read. They are usually located on the nameplate located on the side of the motor. An inspection mirror may be required, just be careful not to read the numbers backwards!

Some air handlers now have the FLA of the blower motor listed right on the nameplate of the equipment. These manufacturers have gone the extra mile to understand the needs of their HVAC contractors.

3. Check the rotation of the fan. “Bump” the fan by depressing the blower compartment safety switch. Check that the blower is rotating in the right direction, that it is tight on the shaft, and that there is no restriction or grinding as the motor turns.

4. Locate the power wire leading to the blower motor. This is normally the wire leading to the air conditioning or high-speed wire on the speed tap. (Remember to normally balance in cooling mode.) If you have a single-phase, multiple-speed motor with speed taps, place the unit in cooling mode with the fan switch in the “on” position and the temperature set to 55F.

One rule of reading amp draw is that only one wire at a time can be measured. Testing two or more at a time will cancel each other out or the reading will be false.

If there is not an exposed wire within the unit, you will have to find an exposed single lead to the motor where you can test. This may be in the electrical disconnect, or at a junction box.

5. Connect the amp clamp from your electrical meter around the power wire.

If the only access to the wire is in the blower compartment, you must be sure that the test is taken with the blower door on, or at least closed as much as possible.

If the door is left off during the test, the fan will move more air than it would if it had to pull all its air through the return air ducting. Therefore, the fan will work harder and the amp draw will be higher than it would be under normal operating conditions.

6. Read the amp draw of the blower motor. Record the reading and compare it to the FLA listed on the motor.

Check the amp draw against the manufacturer's fan performance data to verify the airflow that the fan is producing. A rule of thumb is that on high speed most motors will draw 70-100% of the FLA if it is moving the required 400 CFM per ton on residential systems.

How to apply for Admission in Quaid-e-awam University for 2015-16 Batch

Admission in QUEST Nawabshah 2015-16
Here you can apply for admission  at QUEST Nawabshah easily in few steps and if you have any question about the admission then please comment here we will soon reply you

Electric power Distribution System Engineering By Turan Gonen 2nd Edition

Electric power Distribution
System Engineering
By
Turan Gonen
2nd Edition

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How Density based automatic traffic signals works fully animated.

Urban traffic control (UTC) systems are a specialist form of traffic management which integrate and co-ordinate traffic signal control over a wide area in order to control traffic flows on the road network. Integration and co-ordination between adjacent traffic signals involves designing a plan based on the occurrence and duration of individual signal aspects and the time offsets between them and introducing a system to link the signals together electronically. A traffic responsive signal control system is a means of adjusting the traffic signal settings (cycles, green splits and offsets), which optimise a given objective function, such as minimising travel time or stops, in real-time based upon estimates of traffic conditions. There are many different UTC systems in operation around the world, but they can provide the basis for an extended control system, generally termed Urban Traffic Management and Control (UTMC).

UTC systems can be used to obtain better traffic performance from a road network by reducing delays to vehicles and the number of times they have to stop. UTC systems also can be used to balance capacity in a network, to attract or deter traffic from particular routes or areas, to give priority to specific categories of vehicles such as public transport or to arrange for queuing to take place in suitable parts of the network.

Demand impacts usually reduce travel time, but reduced travel times and good network performance may increase road capacity. This may cause a shift in demand towards car use. UTC systems may not make a positive contribution to all policy objectives.