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Electrical Engineering
Electrical engineering is a field of engineering that deals with the study and application of electricity, electronics and electromagnetism.
23,056 Questions
What is the size of cable for 5 tons ac with three phase supply?
The size of cable required for a 5-ton AC unit with a three-phase power supply will depend on factors such as the distance between the AC unit and the power supply, the voltage level, and the specific installation requirements. It is recommended to consult a qualified electrician or electrical engineer to determine the appropriate cable size to ensure safe and efficient operation.
Why skin effect for a conductor is not applicable for DC?
As we know that skin effect occures in ac system.skin effect dependes on frequncy.In case of dc syastem frequncy is zero.So skin effect for conductor is not applicable for dc.
What is dangerous limit of voltage for 50Hz AC current for adult?
The danger level is dependent on the individual, and the individuals environment. You need to understand the danger of electricity is due to the fact that our bodies operate on electrical impulses. When electrical impulses are induced into your body by forces outside your body that override your brain's signals, bad things begin to happen. The number 1 factor that determines what force (ie voltage) is necessary to "inject" electricity into your body is the resistance of your epidermis. This resistance is impacted by dryness, fat content, stress levels, the presents of salts and other minerals, and a host of other things.
Current flowing through your body in excess of ~20mA at 50Hz can be dangerous. Your body's resistance is likely to be somewhere between 1000 and 500000 ohms. Using ohm's law, as little as 20 volts could, under the right conditions, be dangerous. That is why you should always treat electricity with respect - Don't turn on/off lights with soaking wet hands; don't use electronics plugged into a wall socket in a bathtub, turn off the circuit breaker if you are doing any home wiring that impacts that circuit, etc.
By "Dangerous", I'm referring to the let go current levels. These are the current levels where you no longer have control of whatever part of your body has completed the circuit. At these levels, the signals from your brain are too small relative to the outside influence to tell your muscles to do anything. That's why it's called the let go threshold - you can't let go anymore! As little as 50 volts can cause ventricular fibrillation/death in a matter of minutes.
The voltage of a battery goes as the current times the resistance (V=IR). Because the voltage is being held constant, the resistor that draws the most current will have the lower resistance.
Why red yellow and blue are chosen as three phase supply colors?
easy identification & world electricity standards.
AnswerI understand that, in the UK at least, the colours were originally red, white, and blue. But, for underground distribution cables, the white-coloured paper insulation usually ended up being dyed yellow by the oil-impregnation process, so the colour code was changed to red, yellow, blue. Whether this story is true or not, I cannot say.
How many windings does a single-phase transformer have?
Generally a single-phase transformer will have twowindings. One of the Low voltage side and one on the high voltage side. North-American distribution transformers will have three: one high-voltage winding, and two low-voltage windings connected in series.
However...
...a single-phase transformer can also have several primary and several secondary windings. The primary windings can be connected in series or in parallel with each other, as can the secondary windings. For example, taking the primary winding as an example, it could consist of two 120-V rated windings: if connected in series, it could be supplied with 240 V without exceeding its voltage rating; if connected in parallel, it could be supplied with 120 V without exceeding its voltage rating. Multiwinding single-phase transformers allow for a variety of connections.
What is the fastest kind of diode?
The step recovery diodes are the "fastest" in that, while they may take relatively a long time between when the external voltage becomes negative until they switch fully off, the reverse current stops much more abruptly than other diodes.
The tunnel diodes and Gunn diodes are the "fastest" in that the time after the external voltage becomes negative to the time they switch off is shorter than other diodes.
The Schottky diodes are the "next-fastest" in that the time after the external voltage becomes negative to the time they switch off is very short.
List two important things to remember when using an ammeter?
Make sure it is placed in the circut series so you can measure the electrical current at a specific point.
A trembler bell is a non-polarized bell operated by current that is made intermittent by a contact associated with the bell hammer. It was invented and later patented by J. F. Molaughlin.
Why skin effect is frequency dependent?
skin effect occures in ac system due to un uniform distribution of current in conductor.Ac system has frequency.SO we can say that skin effect is frequecy dependent.
AnswerThe skin effect is caused partly by self inductance which will only occur with a varying current -i.e. with an a.c. current.
When It is required to calculate average voltage and when RMS voltage?
It is usually required in electrical examinations to make calculations. Simple answer to a complicated calculation. Remember, take peak to peak voltage and multiply by .707, the result being average voltage. This is the voltage that electrical test meters read.
I don't understand how a unit of measurement is supposed to be "good" or "bad".
Overall, induced voltage is proportional to the product of the number of loops of coiled wire and the rate at which the magnetic field changes
What is meant by Generator P.f?
the cosine of the angle between voltage and current of generator is called power factor (pf) of generator.
What are the materials of a prank buzzer?
use this link for a prank buzzer chair http://www.instructables.com/id/Awesome-April-Fools-Prank-Buzzer-Chair/step1/Materials/
