Electrical Engineering

pretty close to 1 square inch for 250W

4sqin for 1kw

depend on the R value(s) because V Source = Sum of individual voltage across each R in the series so if R in the series are equal value, then their V are the same and their V total will be equal of the V Source

Your power supply can supply 1 A, but your device requires 2 A. So the power supply will be overloaded. So the simple answer is no.

it is used in voice transmission,to active vibration control and is used in channel vocoder

Divide the wattage by the voltage. If it is 120Volt then the answer is .15Amp

Damaged or frayed wires that can cause shocks or short circuits, loose wire connections that cause sparking, overloaded circuits that consistently trip breakers and overloading extension cords beyond their rated capacity.

High-voltage transmission relies on the fact that for a given amount of power (watts), as the voltage goes up, the current (amps) goes down. The main issue with long distance transmission is voltage drop, which is proportional to current. Consider a transmission system supplying a 1 megawatt load. At 132,000 volts (3-phase), the current will be about 4.4 Amps (132kV X 4.379A X 1.73 = 1MW). Now, even 14 gauge wire would carry 4 or 5 amps, But the wire will have to be much larger than that to limit voltage drop to an acceptable level. The cost of the line itself is relatively small, BUT you have to buy transformers, one for each end! Utility-grade high voltage transformers are enormously expensive, and the hardware for high voltage transmission is also more expensive. Now consider a hypothetical transmission system supplying the same 1MW load, but now our transmission voltage is 4,160 volts. The current would now be 139 Amps! (4,160V X 138.9A X 1.73 = 1MW). You can see that the conductors must be very large to carry that much current. The problem is we still have to make the conductors larger to make up for voltage drop, and we end up with huge conductors. Of course, now you don't have to buy expensive high-voltage transformers! This is an extreme example just to make the point, by the way. At some distance, the cost of the transformers and associated hardware will equal the cost to eliminate them and just use larger conductors. At any distance less than that, it will be cheaper to use the low-voltage, high current setup. At any greater distance, the cost of the transformers, etc. will be more than offset by the cheaper transmission infrastructure (smaller conductors, etc.).

You Don't. 440volt 3-phase is actually 480 volts, taking a single phase gives 277Volts single phase.

To get single phase 440 you would use one leg of three phase 440/760 three phase power.

The amount of current that flows in a circuit is proportional to the voltage and inversely proportional to the resistance, as per Ohms law (I=V/R) where I is current.

When resistances (IE loads) are connected in series, the total resistance is the sum of the loads (IE Rtotal = R1 + R2 + R3 ...)
When they are connected in parallel, the total resistance is the inverse sum of the reciprocals of each resistance (IE 1/Rtotal = 1/R1 + 1/R2 + 1/R3 ...)
Therefore in parallel the total resistance is much lower, and therefore at the same voltage more current will flow.

To answer this question, let's look at the definition of the following words.

Voltage, Current, and Resistance

One volt is one joule of energy per coulomb of electrons. One ampere means one coulomb of electrons is moving through the wire each second.

R = V ÷ I = J/s ÷ C/s = J/C

The resistance measures the amount of energy that is required to make one coulomb of electrons move through the wire. The charge of one electron is 1.6 * 10^-19 C. To determine the number of electrons per coulomb, invert this number.

Number of electrons per coulomb = 6.25 * 10^18

One ampere means 6.25 * 10^18 electrons are moving through the wire and resistor each second. If the resistor is one ohm, one volt will be required for this to happen. To determine the amount of charge that is moving in a wire each second, you will need to wire's resistance and the voltage that is being used. Voltage and resistance determine the amount of charge that is moving through the wire each second. I hope this answers your question.

Once an SCR has been turned on by means of a gate pulse, it latches, or remains on. The only way to turn the SCR off is to either remove the anode to cathode voltage, remove the load current (SCR's have a minimum current below which they will not fire), or reverse bias the SCR. If the SCR is used in an AC circuit, turn off is easy. This is because the voltage falls to zero, then reverse biases the SCR every cycle. This naturally turns off the SCR. In fact, you have to re-trigger the gate every cycle to turn it back on. In a DC circuit, the SCR must be reset by some means as mentioned above. Once the SCR fires, there is nothing you can do to the gate to control the device. The gate only turns it on, not off. There is a similar device, called a GTO, or gate-turn-off device, that can be turned off via the gate. Once an SCR is on it will not turn -off unless the minimum holding current is met. that can be accomplished by reversing anode polarity or by decreasing loading to below holding current

Because higher voltage can carry further.

That answer is too simplistic. The actual reason is as follows: for any given load, the higher the supply voltage, the lower the resulting current. Lower currents mean smaller diameter transmission/distribution conductors can be used and the line losses(I2R) are lower.

A current rating of a fuse is designed to open a circuit at a specific current flow. This rating is imprinted on the fuse and lets you know what the maximum amount of current the fuse is designed to open at. A fuse is in the circuit to protect the conductor that the current flows through. Never over fuse a conductor's current carrying capacity.

that depends on,motor size, number of coils, company,and wire gauge.

you can make a simple dc motor with just 10 winding or less.

it would be very low on torque and speed though.

for three phase the calculation is 30,000 = 1.73*V*I - simple as that.

For single Phase the calculation is 30,000 = V*I - simple as that

It is important to note the voltage in the first line is Line to Line (typically how it is specified in three phase power systems), and the second line it is Line to neutral.

A 30KVA transformer is the same as 30,000VA to find out the Amps you need to divide the voltage if the transformer is single phase for example:

30,000VA / 480V = 62.5 Amps

The calculation for a 3 phase transformer is the VA / voltage / 1.73 for example:

30,000VA /480V / 1.73 = 36.12 Amps

3 core 35 sq mm alu. Or 3 core 25 sq mm cup.

The charge in this case is simply the current multiplied by the time.

The charge in this case is simply the current multiplied by the time.

The charge in this case is simply the current multiplied by the time.

The charge in this case is simply the current multiplied by the time.

There are two conductors were electricity begins and runs through wires which make energy come out of a battery.

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In the center of each cell there is a rod called a cathode. It is usually composed of graphite. Surrounding this cathode there is an electrolytic substance which acts as a medium to conduct electricity. The cathode and electrolytic substance are separated from the outer container by a cardboard tube. This assembly is sealed into a metallic cylinder. In older type batteries this cylinder was made of zinc. This part of the battery is known as the anode. When a load is connected between the cathode (+) and the anode (-) terminals, a chemical reaction takes place between the cathode and the electrolytic material. This chemical reaction generates a 1.5 volt potential between the two terminals.

Your question is better expressed as why can an ac circuit be shorted to earth when a dc circuit can't be? With an ac supply only the positive feed is actually present at the socket. There is no negative, just a neutral return which is actually connected to earth at the power station / substation. Earthing an ac curcuit just provides a shorter route to the earth, which is where it would have gone anyway. The earth connection at the socket is just to provide a safe means of dumping the current locally in the event of a fault. In a dc circuit the current has nowhere to go, other than to the negative terminal / rail. Without both positive and negative being present no circuit can be formed.

An alternating current (AC) is an electric current whose direction reverses cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy.

From line-to-line (any two of the three leads) voltage or 'line voltage', the voltage is 208 V. The line-to-neutral (one of the three leads and the neutral conductor), or 'phase voltage', is 120 V.

Yes you can use. But, Normally DC voltage is 1/5 of the AC rated voltage of the Breaker. So it means if you have 220 volts rated breaker then 44 volts (round up 48) of DC. Because in AC will go every 10 mS (milli Seconds) to Zero in 50 Hz but in DC no break, so in DC the arc on contacts will go to a long distance as compared to DC which may melt more quickly the contacts than AC. At the same time, better, that the breaker specifications mention DC too.