Electrical Engineering

Not much if it is a fixed capaitor. If it is a variable capacitor, rotating the shaft to mesh the two sets of plates more closely will increase the capacitance.

Ionised particles are particles that carry a positive or negative charge. This is due to the loss or gain of an electron or electrons. Losing an electron will cause a particle to become more positively charged, while gaining an electron will cause a particle to become more negatively charged.

No. You need 12 volt AC to run a 12 volt AC motor, not 12 volt DC.

1. Digital multimeters are very high impedance, they therefore draw very little current from the circuit under test. This makes them very sensitive to stray voltages. A voltage reading may not neccessarily mean that there is a useful voltage available on the circuit under test. Take readings other than expected, with a pinch of salt. Understand the circuit under test.

2. A varying, or fluctuating voltage on the circuit under test, is not easy to see from digits. The numbers may just appear to change at random, whereas with an analogue meter, a pulse or variation will be easy to see from the needle movement.

Protective devices - relays, CT,PT, isolators, circuit breakers are used for fault protection. Fault protection means If there is a fault in the circuit, the circuit must be cut off before any damage occurs due to fault.

Have you ever seen the video of the collapse of the Tacoma Narrows Bridge? The Tacoma Bridge was built in 1940. From the beginning, the bridge would form small waves like the surface of a body of water. This accidental behavior of the bridge brought many people who wanted to drive over this moving bridge. Most people thought that the bridge was safe despite the movement. However, about four months later, the oscillations (waves) became bigger. At one point, one edge of the road was 28 feet higher than the other edge. Finally, this bridge crashed into the water below. One explanation for the crash is that the oscillations of the bridge were caused by the frequency of the wind being too close to the natural frequency of the bridge. The natural frequency of the bridge is the eigenvalue of smallest magnitude of a system that models the bridge. This is why eigenvalues are very important to engineers when they analyze structures. (Differential Equations and Their Applications, , pp. ).

Car designers analyze eigenvalues in order to damp out the noise so that the occupants have a quiet ride. Eigenvalue analysis is also used in the design of car stereo systems so that the sounds are directed correctly for the listening pleasure of the passengers and driver. When you see a car that vibrates because of the loud booming music, think of eigenvalues. Eigenvalue analysis can indicate what needs to be changed to reduce the vibration of the car due to the music.

Eigenvalues can also be used to test for cracks or deformities in a solid. Can you imagine if every inch of every beam used in construction had to be tested? The problem is not as time consuming when eigenvalues are used. When a beam is struck, its natural frequencies (eigenvalues) can be heard. If the beam "rings," then it is not flawed. A dull sound will result from a flawed beam because the flaw causes the eigenvalues to change. Sensitive machines can be used to "see" and "hear" eigenvalues more precisely.

Oil companies frequently use eigenvalue analysis to explore land for oil. Oil, dirt, and other substances all give rise to linear systems which have different eigenvalues, so eigenvalue analysis can give a good indication of where oil reserves are located. Oil companies place probes around a site to pick up the waves that result from a huge truck used to vibrate the ground. The waves are changed as they pass through the different substances in the ground. The analysis of these waves directs the oil companies to possible drilling sites.

Eigenvalues are not only used to explain natural occurrences, but also to discover new and better designs for the future. Some of the results are quite surprising. If you were asked to build the strongest column that you could to support the weight of a roof using only a specified amount of material, what shape would that column take? Most of us would build a cylinder like most other columns that we have seen. However, Steve Cox of Rice University and Michael Overton of New York University proved, based on the work of J. Keller and I. Tadjbakhsh, that the column would be stronger if it was largest at the top, middle, and bottom. At the points of the way from either end, the column could be smaller because the column would not naturally buckle there anyway.
Does that surprise you? This new design was discovered through the study of the eigenvalues of the system involving the column and the weight from above. Note that this column would not be the strongest design if any significant pressure came from the side, but when a column supports a roof, the vast majority of the pressure comes directly from above.

Ready to parlay your knowledge of linear algebra into fame and fortune? Read "The 25,000,000,000 Eigenvector: The Linear Algebra Behind Google". (the seventh link below)

energy source :)

A reactor is composed of a coil of wire. A transformer is at least two coils, wrapped around a core. The core provides a path for the magnetic flux, which results in strong magnetic coupling between the coils. This allows a voltage applied to one coil to be induced in the second coil.

With this in mind, some differences are:

-Function - a reactor can be used in filters, to control system voltage (pull extra VARs off the bulk electric grid), and to isolate circuits from a noisy ground, among other things. A transformer can be used to step voltage or current up or down, and to isolate circuits from eachother, among other uses.

-Size - Reactors are inherently smaller than transformers. You likely have some reactors in your computer monitor that look very much like resistors. Transformers are much more obvious. Utility size reactors can be as big as utility transformers, though.

-Terminations - A reactor is a two - terminal device. A transformer will have at least three, and likely many more terminals.

-Cost - Reactors are cheaper - last time I purchased for a small signal design project I spent as little as 20 cents (US) per reactor. The last small transformer I purchased was $6.00. When you start getting into larger sized equipment, the difference becomes less extreme.

The linear induction motor works on the same principle as that of normal induction motor with difference that instead of rotational movement, the rotor moves linearly. If the stator and rotor of the induction motor are made flat then it forms the linear induction motor. The flux produced by the flate stator moves linearly with the synchronous speed from one end to the other. The synchronous speed is given by,

v

s = 2wf

where v

s = Linear Synchronous Speed (m/s)

w = Width of one pole pitch (m)

f = Frequency of supply (Hz)

It can be seen that the synchronous speed is independent of number of poles but depends only one width of pole pitch and supply frequency.

The CPU or processor

Firstly turn of the power before this test...
Using a resistance or continuity tester you should get the following results:

Short circuit: Very low resistance (nearly 0 ohms) or the bell will ring.
Open circuit: Very high resistance (Somewhere in the range of Mega ohms) or the bell will not ring.

The reason for this is because and open circuit has a gap in it (which has high resistance).
The short circuit has wires that are crossed and so has a really low resistance.

amps

Much to my dismay i found its an experimental value, depends on type of core, cooling tech, resistance of wiring etc.

It may not be possible to physically convert AC generator to DC generator. What can be done is that 'Rectifier' of suitable capacity can be connected to the out put of AC generator to get DC supply.

With a constant voltage and increase in wire length will increase the end to end resistance and therefore the current will decrease.

AMF stand for Auto Mains Failure. Generally a generator/alternator power and normal commercial line switching over is done through it. A normal changeover, if mains fails you have switch the load circuit to generator, and when mains restors, generator supply will be cut off and fed to mains.

in AMF this done by contactors and control circuits.

if you want to know more......

motor can be control by using variable frequency drive

The equation for parallel circuit is:

1 / X = 1/R1 + 1/R2 + ... + 1/RN

Plug in the known resistances:

1 / 25 = 1 / 220 + 1 / X

Solve for X:

1 / 25 - 1 / 220 = 1 / X

8.8 / 220 - 1 / 220 = 1 / X

7.8 / 220 = 1 / X

X = 220 / 7.8

X = 28.20512821

For those who need a three-phase supply, they are essential. If a single-phase supply is needed, a three-phase generator is uneconomic.

Three-phase is used for loads of more than about 15-20 kVA.

A: Brown B: Orange C: Yellow Neutral: Grey Ground: Green or Green with a yellow stripe.

Since power is current times voltage, doubling current while keeping voltage the same will double the power. Ignoring slight non-linearity, if the power doubles, the heat will double.

Cable tray is a system of wiring in a building in which insulated electrical wires are used to distribute power and communication to various access points. Cable trunks are power supply lines that are used to distribute power and communication services to large areas such as industrialized cities.

The English term mains electricity usually refers to the general purpose alternating current (AC) electrical power supply. The term is not often used in the USA and Canada. There, mains power has a variety of names: These include household power, household electricity, domestic power, wall power, line power, AC power, city power, and grid power. So you see, that a mains adapter must be a power adapter.