Electrical Engineering

Inherently, the actual impedance seen at the secondary voltage will be different than that seen at the primary voltage. To make things easy, we use symmetrical components, where transformers are reduced to a p.u. (per unit) impedance. 100 x p.u. is equivalent to the percentage impedance you are referring to. When converted to per unit, a transformer has one impedance, not two, so it does not matter whether you are looking through the transformer from the secondary or the primary.

Torque is a measure of how much a force acting on an object causes that object to rotate. Speed is how fast something is going. Another way to think of this is as how far you can go in a certain amount of time.

polarity is of major importance in dicect current circuits.

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When using meters please remember that a volt meter does not connect into a circuit, the leads are placed across the component that you are measuring. It is an amp meter that connects into the circuit, becoming part of the circuit, to measure the current flowing through that circuit.

Multimeters measure AC in two primary ways... The older style meter uses a diode, capacitor, and resistor to measure the peak voltage of the AC signal. They then compensate their calibration to read in a close approximation of what the RMS value will be. Problem is that this only works well for true sinusoidal waveforms - if the waveform is triangular, for instance, the indicated value will not match the RMS value. The newer style meter, if it states that it is a true RMS meter, will sample the input waveform and actually calculate the RMS value. This is done by adding up the squares of the input, and then taking the square root of the result. That is a much better approximation of how much power the waveform can deliver.

"60 Hz" means "60 cycles per second".

Each cycle lasts 1/60th of a second = 16-2/3 milliseconds

In general, increased resistance will lower current draw.

See ohm's law (V = IR)

first calculate the full load amps of the motor by using formula,

line amps = KW * 1000 / (line volts*1.732*P.F)

Of the mentioned motor the amps will be 96 amps at the P.F 0.8. The motor will have star delta starter so the cable size would be 2 runs of 3c x 70 sq mm AL if laid in air.

False

This seems like a question from an electrical course, and is probably best answered by your course materials. It's your test question, not ours, and there won't always be someone to ask the answer of. Earn your diploma.

Most electrical wires use unalloyed copper. The exception is high-power overhead lines that use aluminium for its low density, which means there is a lot less mass for the towers to support, so they are lighter and less expensive.

Aluminium overhead cables are either ACSR - aluminium core, steel reinforced, which uses multi-strand cables with steel strands in the centre; or AAAC which is all-aluminimum alloy conductor.

AAAC cables use an aluminium-magnesium-silicon alloy with silicon 0.5-0.9%, magnesium 0.6-0.9%, iron 0.5% max, copper 0.1%, manganese 0.03%, chromium 0.03%, zinc 0.1%, boron 0.06%. The purpose of adding other elements is to increase the tensile strength of the conductors so they can be tensioned up without too much dangling.

Applications of Voltage shunt feedback amplifier?

Basic componets of a plc are: power supply, CPU(central prossesing unit), I/O CARDS ( INPUT/OUTPUT CARDS)

The answer to the question as phrased is yes, unless you run a factory in your house. 25kW is a substantial amount of power. However, you probably meant "how much energy is 25kWh?" This is about the amount of energy needed to run 25 electric kettles for an hour, or two electric kettles for a day. It's still quite a lot.

The 240 volts coming in is coming from two separate 120 volt lines (phases). In your home, it's called single phase, although it really should be called two phase or double phase. In the box, there are two "hot" wires coming in, and one "neutral" wire. You add a ground wire to that yourself (check local codes).

Basically (this is very simple description), one of the hot wires gives 120 volts, and the other gives 120 volts, but just a little bit behind the first phase. If you pull the cover off your electric panel, you would see two "hot" wires connected to two separate 'bus bars'. Every other slot on the left side of the breaker box is connected to hot 1, and the alternate slots are connected to hot 2. When you need 240 volts, the breaker you install will take up two slots, adding the 120 (hot 1) plus 120 (hot 2) to give you 240. For your regular plugs, a single slot breaker will deliver 120 volts.

If you have a 240 volt plug, it will normally have 4 prongs. Two of the prongs have 120volts each (relative to ground) and 240 volts relative to each other (due to the lagging/leading phase difference.)

None: "high tension" is just another way of saying "high voltage".

For the same power - Watts - you need to run twice as many amps at 220V than at 440V.

For the same load, it'll pull half the amps at 220V than it did on 440V

A: If there is resistance within the device it will cause to dissipate some of the energy as heat. The rest will continue

Any coil produces a magnetic field when it has an electic current passing through it.

It's usual to use copper wire, and 1 amp through ten turns has the same effect as ten amps through one turn . . etc.

Voltage Rise : The energy added to a circuit.

Voltage drop: The energy removed from the circuit.

Power=Volts x Amps Unit for power is watts

light can be altered by using different types of gas and varying the pressure in the bulb. Gases such as neon, argon, krypton, mercury, and xenon allow electric-discharge lamps to be used in a variety of applications

Work is usually measured in joules, which are a unit of energy. Work/time is called power and is usually measured in Watts (joules/second) other common units of power include Horsepower and ft*lbs /sec.

in short, is is power, which is measures in watts.

Electrical angle is half of mechanical angle in unipolar electrical machines. In multipolar electrical machines, the relationship between the mechanical angle and electrical angle is Electrical angle = (P/2) x Mechanical angle where: P = Number of poles.