What is the difference between KW and KVAR?

Answer 1

kW is the unit of real power & kVA is the unit of Apparent power.

Apparent Power= real power + reactive power

Besides this,the ratings which we write on a motor or generator is KVA & not KW. B'coz there are two types of losses in a motor or generator- core losses & ohmic losses. Core loss depends upon the voltage applied & ohmic losses depend upon the current flowing & none of these losses depend upon the power factor i.e. Cos@. As we know that

KW power = V * I *Cos@.

But as the losses are independent of the power factor hence we need to calculate only KVA = V*I.

Comment

Apparent power is the vector sum of real power and reactive power, not the sum.
KVA is the unit of apparent power and KW is unit of active power.

KW is kilowatts, and KVA is kilovoltamps. KW is the apparent power that a normal power meter would measure, while KVA is simply the maximum of the instantaneous product of volts and amps divided by 1000. The difference between these two terms is due to phase angle, which is due to the reactance of the load to an AC power source.

KW (kilowatts) is apparant power, while KVA (kilovoltamps) is true power. They are different when the phase angle between voltage and current is not zero, i.e. when the load is reactive, such as in a motor. The ratio of KW over KVA is Power Factor, and is the cosine of the phase angle between voltage and current. It is zero at a phase angle of 90 degree, which occurs for purely (ideal) inductive or capacitive loads with no resistance in the source or conductors, and it is one for purely resistive loads.

Answer 2

kw means total usefull power if the power factor is unity

Alternative Answer

The symbol 'kW' (not 'kw') represents 'kilowatt', and the symbol 'kV.A' (not 'kva') stands for 'kilovolt ampere'.

In a.c., the product of supply voltage and load current is called 'apparent power', and is expressed in volt amperes. To determine 'true power', expressed in watts, you must multiply apparent power by the power factor of the load.

apparent power = voltage x current

true power = voltage x current x power factor

Power factor is the cosine of the angle by which the load current leads or lags the supply voltage.

Answer 3

kV is kilovolt, whereas kV.A stands for kilovolt ampere. Kilovolt means the potential difference measured between two points. Kilovolt ampere is the apparent power of an electrical load.

kV is kilovolts, while kV.A is kilovolt-amperes. kV is a measure of voltage, in kilojoules per coulomb, while kV.A (and kW, kilowatts) is a measure of power, in kilojoules per second.

kV.A and kW are related, in that they are both a measure of power. The difference there has to do with power factor in a reactive circuit, such as a motor.

Answer 4

KW is kilowatts, and KVA is kilovoltamps. KW is the apparent power that a normal power meter would measure, while KVA is simply the maximum of the instantaneous product of volts and amps divided by 1000. The difference between these two terms is due to phase angle, which is due to the reactance of the load to an AC power source.

kVA is apparant power, while

KW (kilowatts) is true power. They are different when the phase angle between voltage and current is not zero, i.e. when the load is reactive, such as in a motor. The ratio of KW over KVA is Power Factor, and is the cosine of the phase angle between voltage and current. It is zero at a phase angle of 90 degree, which occurs for purely (ideal) inductive or capacitive loads with no resistance in the source or conductors, and it is one for purely resistive loads.

Not asked, but answered for completeness: Also a component is KVAR, or kilovoltamps-reactive, which is a measure of reactive power. There is also reactive power factor, KVAR over KVA, which is the sine of the phase angle, but this is not commonly used. It is one for purely inductive or capacitive loads with no resistance in the source of conductors, and it is zero for purely resistive loads.

Answer 5

Yes. KW is real power, while KVA is the sum of the vectors of real and reactive power.

Put another way, KW output (of a generator, for example) can be defined as the KVA at a specific power factor.

Answer 6

On the ligher side:

(Norwegian has got two forms. Bokmål and Nynorsk)

In Nynorsk,

Kvar mean the same as "Where?" and

Kva mean the same as "What?".

Answer

To answer the question...

Typically, an alternating-current load is resistive-reactive. In other words, it has resistance and either inductance or capacitance. For example, a motor is typically a resistive-inductive load.

The rate at which energy dissipated by a resistive load is called true power, which is measured in watts(W).

The rate at which energy is alternately stored (in the magnetic or electric field) and, then, returned to the supply by the reactive load is called reactive power, which is measured in reactive volt amperes (var).

The overall rate of transfer of energy is called apparent power, and is measured in volt amperes(V.A), where apparent power is the vector sum of true power and reactive power.

Answer 7

Electrical power absorbed by the load is a combination of real power as a heat ( I2R) and is measured in KW, but the second port of energy consumed is in the form of imaginary power ( for inductive and capacitive loads ) like a motors , compressors and is measured in KVAr .

Answer 8

In an ac system the kVA is the product of the kV and the amps. But in some loads such as electric motors the current is not in phase with the voltage so some power flows from the load back into the supply for a fraction of the ac cycle. That means that the average power flow in kW is generally less than the kVA by a factor known as the power-factor. The ideal power factor is 1 and power factors of less than about 0.8 are not good because the current supplied, and therefore the power loss in the cable, is more than necessary for the given amount of power. In many cases the power factor of high-power loads can be corrected by adding special components.