Understand kVA kW Relation
KiloVolt-Amperes in short kVA is the unit estimating evident power and KiloWatt in short kW is the unit estimating real power. The connection between kVA and kW are corresponding. kW is the measure of 'actual power' an electrical framework has. This gives you how much power is being changed over into an effective, working yield. kVA, then again is the proportion of 'apparent' power. If kW is the amount of force you can work with, kVA reveals to you the amount that is being used in the framework by and large. On the off chance that the productivity of an electrical framework is excellent, at that point kW would be equivalent to kVA.
kW to kVA Formula
In the kW to kVA calculations, the kW to kVA conversion formula is -
kW = kVA × PF
Where,
kW is the unit estimating real power.
kVA is the unit estimating apparent power.
PF is the Power Factor.
In the kW to kVA conversion, kW is directly relative to kVA, which implies that-
When kW increments, kVA will increment.
When kW declines, kVA will diminish.
When kVA declines, kW will diminish.
When kVA increments, kW will increment.
In mathematical terms, we can write it as:
kW = kVA x PF
kVA to kW Calculations
The conversion of kVA to kW; these two units of power are significant to solve many problems in Physics. kVA to kW formula is:
kVA= kW/PF
For example: If the Power factor is 0.2 and kW is 150 then kVA = 150/0.2 = 750 kVA.
kW to kVA Calculations
To convert kW to kVA; The power units are essential to solve kVA calculations in Physics.
To convert kW to kVA-
kW=kVA×PF
Example: If the Power Factor is 0.2, and kVA is 150 then to convert kW to kVA
kW=150kVA×0.2 = 30kW
Convert kWH to kVA
Just like kW to kVA conversion, A kilowatt-hour (kWh) is the measure of the energy a circuit working at a kilowatt of power moves through the span of 60 minutes. This unit is equivalent to 3,600,000 joules. The kilovolt-ampere (kVA) is the power rating of a circuit conveying 1,000 volts and an ampere or 1,000 amperes and a volt. A single kilovolt-ampere is comparable to a kilowatt. To change over from kilowatt-hours to kilovolt-amperes, you have to know just the time the circuit takes to move the energy. Measure the time length for which the circuit runs.
Difference Between kW and kVA
The main difference between kW (kilowatt) and kVA (kilovolt-ampere) is the power factor. kW denotes the unit of real power and kVA denotes the unit of apparent power. The power factor, which is defined and known, is, therefore, an approximate value (typically 0.8), and in the kW to kVA calculations, kVA value will always be more than the kW value.
Under industrial as well as commercial generators, kW is most commonly used in the US generators. The majority of the rest of the world mainly uses kVA as the set of generators.
To explain it a bit more, the kW rating is primarily the result of power output a generator can supply based on the engine’s horsepower. kW is figured by the horsepower rating of the times of engine 0.746. For example, if you have a 600 horsepower engine, it has a kW rating of 473. The kilovolt-amperes (kVA) are the generator capacity end. Generator sets are displayed with both ratings usually.
To determine the kW to kVA calculations ratio, the kW to kVA formula below is used.
0.8 (pf) x 750 (kVA) = 600 kW
Solved Questions
1. Convert the Real Power in Watts to Apparent Power in kVA (Kilovolt amps).
Solution: S in kilovolt-amps (kVA) which is the apparent power is equal to the P in watts (W) which is the real power, divided by 1000 times the PF:
S(kVA) = P(W) / (1000 × PF)W
Watts divided by 1000 times the power factor is equal to kilovolt-amps.
kVA = kW / (1000 × PF
Fun Facts
A fraction of kVA is only accessed to do any work, and the rest fraction is considered current.
kW represents the actual power that does the valid work.
When we consider a DC circuit, the kW and kVA are both equal because of the reason that the current does not go out of phase. But in the case of AC circuits, many differences can be found.
Points to Remember with the Relation Between KVA and KW
The Relation between KVA and KW is one the most interesting topics from the Class 11 and 12 Physics part which deals with Electrical concepts and their applications. At a higher level, the relationship between KVA and KW is one of the most talked-about in electrical engineering and electronics engineering. Hence, the relation between KVA and KW finds its relevance in school-level exams as well as higher technical examinations as well.
Hence, students should be ready with all the basic concepts at their fingertips which will ensure that they will be able to answer any questions appearing from the topic of the relation between KVA and KW. Vedantu has come to the rescue and solved all the queries of the students by providing free and necessary learning materials which will ensure that students will be able to grasp important concepts and tips and tricks to make sure they will be able to remember them as well. Here are the points to remember in the relation between KVA and KW:
KVA is used to represent the apparent power in the circuit. On the other hand, KW is used to determine the true power in the circuit. True power and apparent power, both are the components of power in the circuit.
KW or true power or actual power is the measure of how much power has been useful in the circuit, which means KW represents how much power has been able to generate the output in the power system.
KVA is the measure of the power that can be generated from the power circuit. It does not necessarily mean that all of KVA or the apparent power will be useful or will be able to generate any output in the system. We can say that apparent power is the calculated power or the expected power provided by the power circuit. However, the actual power generated by the circuit is lower than the apparent power.
The relationship between apparent power and true power is established with the help of the efficiency of the power factor. Students can learn about power factors on Vedantu.
FAQs on Relation Between KVA and KW
1. What is the fundamental difference between kW (kilowatt) and kVA (kilovolt-ampere)?
The fundamental difference lies in what they measure. kW (kilowatt) represents Real Power, which is the actual power used by an electrical system to perform work. In contrast, kVA (kilovolt-ampere) represents Apparent Power, which is the total power flowing in the system, including both the power that does work and the power that sustains the magnetic field (reactive power). Essentially, kVA is the vector sum of real power (kW) and reactive power (kVAR).
2. What is the formula to convert kVA to kW?
To convert kVA to kW, you must know the Power Factor (PF) of the electrical circuit. The formula is:
kW = kVA × PF
For example, if a generator is rated at 100 kVA and has a power factor of 0.8, its real power output is 100 kVA × 0.8 = 80 kW.
3. What is the Power Factor and why is it crucial for understanding the relation between kVA and kW?
The Power Factor (PF) is the ratio of Real Power (kW) to Apparent Power (kVA). It is a dimensionless number between 0 and 1. The Power Factor is crucial because it indicates how efficiently electrical power is being converted into useful work. A higher power factor means higher efficiency. It is the critical component that links kVA and kW; without it, you cannot determine how much of the apparent power (kVA) is actual, usable power (kW).
4. Why are electrical devices like generators and transformers rated in kVA instead of kW?
Manufacturers rate devices like generators and transformers in kVA because they do not know the power factor of the loads that will be connected to them. The device's internal components, such as windings and conductors, are designed to handle a specific maximum current (amperes) and voltage (volts), which together define the apparent power (kVA). Since the real power (kW) depends on the load's power factor, rating in kVA provides a load-independent measure of the device's maximum capacity.
5. When are kW and kVA values equal, and why is this uncommon in AC circuits?
The values of kW and kVA are equal only when the Power Factor is 1 (unity). This occurs when the circuit's voltage and current are perfectly in phase. This scenario is typical in simple DC circuits or purely resistive AC circuits (like heaters or incandescent bulbs). However, it is uncommon in most real-world AC circuits because they almost always contain inductive or capacitive elements (like motors, transformers, or fluorescent lights), which cause the current to lead or lag the voltage, resulting in a power factor less than 1.
6. How does the 'power triangle' help visualize the relationship between kW, kVA, and kVAR?
The power triangle is a right-angled triangle that provides a graphical representation of power in an AC circuit:
- The base of the triangle represents Real Power (kW), the power that does useful work.
- The height (perpendicular) represents Reactive Power (kVAR), the power required to sustain magnetic fields in inductive components.
- The hypotenuse represents Apparent Power (kVA), which is the vector sum of real and reactive power.
This visualization clearly shows that kVA will always be greater than or equal to kW, and the relationship is governed by the angle between them, where the cosine of that angle is the power factor.
7. How do you convert 10 kVA to kW if a machine has a typical power factor of 0.8?
To convert 10 kVA to kW with a power factor of 0.8, you use the standard conversion formula:
kW = kVA × Power Factor
Plugging in the values:
kW = 10 kVA × 0.8
kW = 8
Therefore, a machine rated at 10 kVA with a power factor of 0.8 can deliver 8 kW of real, usable power.
