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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
How can you do the polarity test of a switch?
A 'polarity test', as it applies to a switch, is performed to confirm that the switch is located in the line conductor and not in the neutral conductor.
Ohm's law: Current = voltage divided by resistance
240 volts divided by 0.2 ohms = 4,800 amperes.
1,152,000 watts, by the way, so don't even think about trying it.
How you improve power factor in synchronous motor?
Power Factor measures the difference in phase between the current and voltage. When they are in phase the Power Factor is defined as 1. When out of phase the value is less than 1. If they are 180 degrees out of phase the Power Factor will be zero.
How do you use a multimeter to measure a short?
1.) Turn all the power in the circuit off. 2.) In volts mode (both AC and DC) check to make sure there is no power. 3.) In ohms mode check to see if the resistance is close to zero. (Check zero by connecting the leads together momentarily.) Note that light bulbs will have far less resistance cold than when hot, due to their negative temperature coefficient, so you should remove them, and that transformers and motors will appear to have zero ohms due to their inductive reactance, so they will also need to be pulled from the circuit.
544 million kilowatts equals how many megawatts?
1 megawatt = 1,000,000 watts
1 kilowatt = 1,000 watts
So 544 million kilowatts is 524,000,000,000 watts. In megawatts this is 524,000 MW. Or 524 gigawatts (GW)
Voltage across a resistance = (resistance) x (current through the resistance) =
4 x 1.4 = 5.6
If the ' 1.4 ' is Amperes of current, then the required voltage is 5.6 volts.
Do they make 3 phase oven for home use?
Three phase ovens are made for home use. It is important however to know if the home is wired for three phase or for single phase.
Why is there a high voltage line on 3 phase?
The high leg is a byproduct of another feature. It is not in and of itself useful. On a three phase delta transformer, one of the three windings (only one) is center tapped to create a neutral - from the nearest two phase legs to the center tap you get a half voltage which can be used for lighting. (typical arrangements are phase-to-phase = 240 volt, phase to neutral = 120 volts) From the third, furthest phase leg you get the unusable high leg. (208V)
What is the size breaker per phase 200kva generator?
if you have 200 kva so it's 160 KW then ,you need 400 A MCCB and setting at 0.9 and use cable 4c.185 mm2 if the SMDB is nearby and all this will be change according to the ambient temperature and the electrical code used in your area
How much does a wind farm cost to build?
Considering the fact that a 500MW coal-fired plant can cost upwards of $1 billion just for land acquisition and construction (not considering operational and maintenance costs or fuel costs), a wind farm with equivalent energy output, zero emissions and no-cost fuel (wind) comes in at about $600 million.
'Equivalent energy output' is incorrect. The original author is confusing 'installed capacity' - the power it could generate under ideal conditions - with output. This is a very important distinction.
For example, if you have 500MW of coal capacity and 500 MW of wind capacity, as long as you have optimal fuel for each system, they will output the same amount. In the case of coal, the operator can control the fuel supply (mostly) and run at any percentage of peak capacity for as long as is desired, up to 100% of the time. For wind, the operator is at the mercy of how much and how fast the wind blows and can only operate at peak capacity when conditions are perfect, which is less than 15% of the time. The concept is called 'capacity factor'.
Why is gain affected when the bypass capacitor is open?
Applied input signal at the base of the amplifier appears across the emitter resistor (RE) due to inter electrode capacitance so it should be bypassed the emitter resistor (RE) through the bypass capacitor (CB). unbypassed signal will be amplified (common emitter amplifier) and reverse back from the emitter to the collector through the base, amplified signal from the emitter to the collector (common emitter amplifier) is 1800 out of phase to the amplified signal from the base to the collector (common base amplifier), so reduced the gain.
Where ac voltage controllers are used?
AC voltage controllers are used for controlling the speed of universal motor or induction motor by changing the firing angle :) -vinodh gav
What precautions to be taken when working with Transformer?
Frist putt of the main incomer HT side then Rack out the breaker and put the LOTO after that Discharge the cable Both side (HT/LT).
What is the difference between single pole mcb and double pole mcb?
A single pole circuit breaker can protect one hot wire to a given load where as a two pole circuit breaker can protect two hot wires to a given load. In the North American system this would equate to 120 volts on a single pole circuit breaker and 240 volts on a two pole circuit breaker.
How can one convert 180 VDC to 24 VDC?
If you are talking about alternating current you would use a step down transformer with the primary being 240 volts and the secondary being 24 volts.
The total resistance would be 40 ohm.
Which voltmeter will used for measuring 50kv dc?
Any standard voltmeter but however the voltage to be measured must be stepped down to a safe value using a Potential transformer.
What classes to take in high school to become an electrical engineer?
None. An electrical engineer is educated by an ABET accredited university. However, a solid high school educational background in math and physics may help one to master electrical engineering in college.
What is the difference between an open delta and an open wye connection?
An open delta connection is a delta connection with one phase removed, but still supplied with three line conductors. An open wye is a wye connection with one phase removed, supplying a three line conductors and a neutral conductor.
An open-delta/open-wye is a method of providing a reduced-load three-phase supply using just two single-phase transformers, rather than the preferred method of using three single-phase transformers.
Why brushes are made of only carbon graphite in dc machines?
The brushes are made up of carbon because it has low friction as compare to other materials and cheaply also, but carbon has high resistance due to which output can vary. So we mix carbon with copper metal to reduce resistance.
Note that we cannot use copper only for brushes because it creates more friction with commutator.
What is the SI unit of charge?
coulomb
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Coulomb (symbol C) is a derived unit for electrical charge in SI; the base units are:
1 C = A x s
So, the coulomb is the electrical charge transported by an ampere in one second.
