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In an AC system power is equal to Voltage x Current x Power factor. Power factor is not constant and depends on the type of the load. Ideal value of the Power factor is 1, where as practically remains less then 1.

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Q: Why Voltage x Current do not equal rated power?
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What is meant by rated voltage rated current and rated power of a transformer?

The ratings state the limits on voltage and current for operating the transformer at full load. The rated voltage times the rated current gives the rated VA of the transformer. Transormers are not usually rated directly for power because this depends on the power factor of the load applied.


What is meaning of apparent power in transformer?

Apparent power is the product of voltage and current in an a.c. system, and is expressed in volt amperes. The rated apparent power of a transformer is the product of its rated secondary current and rated secondary voltage.


What is current carrying for 2200kVA transformer?

Presumably you are asking about the rated secondary current of a transformer rated at 2200 kV.A?This depends on the rated secondary voltage. You divide the rated apparent power of the transformer by the rated secondary voltage.Of course, the actual current depends on the load.


Why the rotor of an alternator at rated power dissipates more heat at a low power factor load?

In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)


Why ups rating is in kva?

The kva rating includes the power factor of the connected load.KW * Power Factor = kva.AnswerThe above answer is incorrect, as it's actually kV.A x power factor = kW.The answer is straightforward, the output of the UPS is the product of its rated output voltage and its rated output current, and the product of voltage and current is 'apparent power', expressed in volt amperes.

Related questions

What is meant by rated voltage rated current and rated power of a transformer?

The ratings state the limits on voltage and current for operating the transformer at full load. The rated voltage times the rated current gives the rated VA of the transformer. Transormers are not usually rated directly for power because this depends on the power factor of the load applied.


What is meaning of apparent power in transformer?

Apparent power is the product of voltage and current in an a.c. system, and is expressed in volt amperes. The rated apparent power of a transformer is the product of its rated secondary current and rated secondary voltage.


What is the current of a 45 kva transformer?

Presumably, you are asking what is the rated secondary current for a 45 kV.A (not 'kva') transformer? The answer depends on its rated secondary voltage. To obtain the rated secondary current, you divide the (apparent) power rating by its secondary rated voltage.


What is rated voltage and current in transformers and how to calculate them if given 50k VA?

Rated voltage is the voltage at primary side. Rated current can be found from the equation, Rated Current= Output KVA / Output rated voltage


If the voltage in a resistive is double the power will be?

In a resistive load circuit, the power = multiplication of voltage and Current. By increasing the voltage power will not be increased. Power is defined by the load as per its design. If the voltage is higher the load current will reduce. However running a load at double the rated voltage is not good for the device. Insulation may fail.


How do you calculate MVA rating of power transformer?

The product of the secondary rated current and the secondary rated voltage will give you the rated V.A of the transformer.


How do you tell the voltage of landscape lights?

take the power it needs and the current it pushes, and divide.V=P/IAnswerLook at the nameplate of the voltage converter -it will specify the output voltage to the lamps. Alternatively, look at one of the lamps, it should have its rated voltage printed on it together with its rated power.


Why ups rated in kva?

The kva rating includes the power factor of the connected load.KW * Power Factor = kva.AnswerThe above answer is incorrect, as it's actually kV.A x power factor = kW.The answer is straightforward, the output of the UPS is the product of its rated output voltage and its rated output current, and the product of voltage and current is 'apparent power', expressed in volt amperes.


Relationship between current and brightness of a light bulb?

the current is a factor that affects the brightness of the bulb but there are other factors such as if the circuit is in series or parallel. Overall though the current does affect the brightness of the bulbAnswerFor a lamp to operate at its rated power, it must be subject to its rated voltage. It's as simple as that! This is why a lamp's rated power is listed together with its rated voltage on the glass envelope of any lamp. If the voltage is allowed to fall below its rated voltage, then its power output will fall; in fact, a small fall in voltage will result in a proportionally-larger fall in power.


Why unity power factor is used in load test?

When power factor is at unity, the voltage and current waves are aligned or in phase with one another. Since power is the product of voltage and current, power transfer is maximized at unity power factor. When power is transmitted at a lower power factor, greater current is required to deliver the same amount of power. When current is increased, the size of the transmission, distribution and generation systems, all have to be increased accordingly, along with the price of the killowatt-hour at the meter.


What is current carrying for 2200kVA transformer?

Presumably you are asking about the rated secondary current of a transformer rated at 2200 kV.A?This depends on the rated secondary voltage. You divide the rated apparent power of the transformer by the rated secondary voltage.Of course, the actual current depends on the load.


Why the rotor of an alternator at rated power dissipates more heat at a low power factor load?

In an alternator, the load current is supplied by the stator and the excitation is applied to the rotor. When the power factor is low (lagging), more excitation is required to maintain rated output voltage at rated current. More excitation is also required to maintain rated output voltage with increased output current. Increased excitation current means increased rotor losses that must be dissipated as heat. (akash)