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VA, or volt-amperes, is a measure of the output of the transformer. VA is also called apparent power. Watts on the other hand, is also called true power. If the transformer feeds a resistive load, then watts are equal to VA, because the voltage and current are in phase. If the transformer feeds a reactive load, such as a motor, then the voltage and current are no longer in phase, and the true power (watts) is less than apparent power.

Since the true power, or watts delivered can change depending on the load, it is not very useful as a transformer rating. The VA remains constant irregardless of the load characteristics, and so is a much better indicator of transformer performance.

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Why transformer rating is called kva not kw?

Transformers are rated in KVA because that is a more accurate way to measure their capacity requirements. KWH is apparent power, while KVA is true power, and the ratio between them is power factor. The power factor is a function of the load, and not the transformer, so a poor power factor would make KWA look less to the transformer while, in fact, the true power, if not met by the transformer, could overload the transformer.


How do we Calculate Kwh to Kvah?

To convert 'kwh' to 'kvah' you first need to measure the length of time. You will then convert this amount to hours by dividing by 3,600. You will then divide this amount by the length of time.


How do you convert kwh to amps?

There is no kva in volts, kva stands for kilo = 1000, volt = working voltage, amps = maximum amperage draw at that voltage. eg. 1000 VA =100v at 10 amps or 200v at 5 amps. If you had a transformer that had a primary voltage of 480 volts and you need a secondary voltage at 240, with a maximum load of 5 amps, the transformer rating should be 1.2kva or 1200VA. On the premise 480V primary, amperage will be 2.5 amps. Secondary 240V, amperage will be 5 amps. 480 x 2.5 = 1.2 KVA, 240 x 5 = 1.2 KVA. Transformer size is 1200 VA or !.2 KVA.


How to convert kva-kwh?

To convert from KVA (kilovoltamperes) to KWH (kilowatthours) first convert to KW (kilowatts) by multiplying by power factor. Power factor is the cosine of the phase angle between voltage and current. Then multiply by the number of hours that you run the load.


How do you calculate 3 phase kWh from amps measured on each phase?

The voltage and current will give the kVA, but the kW depends on the power factor of whatever load is connected to the supply. For a (let's say) 11 kV supply, the voltage from line to neutral is 11,000/sqrt(3) which is 6351 v. The kVA on each phase is 6.351 times the current, and you just add up the three kVA values to find the total. At higher voltges like 11 kV the three currents in the lines are usually very nearly equal.

Related Questions

Why transformer rating is called kva not kw?

Transformers are rated in KVA because that is a more accurate way to measure their capacity requirements. KWH is apparent power, while KVA is true power, and the ratio between them is power factor. The power factor is a function of the load, and not the transformer, so a poor power factor would make KWA look less to the transformer while, in fact, the true power, if not met by the transformer, could overload the transformer.


What ratio ct to use for a 250 to 5 rated kwh meter?

The ratio would be a 50:1 current transformer.


How do we Calculate Kwh to Kvah?

To convert 'kwh' to 'kvah' you first need to measure the length of time. You will then convert this amount to hours by dividing by 3,600. You will then divide this amount by the length of time.


How do you convert kwh to amps?

There is no kva in volts, kva stands for kilo = 1000, volt = working voltage, amps = maximum amperage draw at that voltage. eg. 1000 VA =100v at 10 amps or 200v at 5 amps. If you had a transformer that had a primary voltage of 480 volts and you need a secondary voltage at 240, with a maximum load of 5 amps, the transformer rating should be 1.2kva or 1200VA. On the premise 480V primary, amperage will be 2.5 amps. Secondary 240V, amperage will be 5 amps. 480 x 2.5 = 1.2 KVA, 240 x 5 = 1.2 KVA. Transformer size is 1200 VA or !.2 KVA.


Why you used different Current Transformer ratios?

The selection of CT Sizing is based on total connected load. If for example a Main CB of 2000 KVA Trafo is 4000 A -- then best selection would be 4000:5 -- this would match also in the Energy Meter (KWH Meter) with 800 as multiplier.


Is there a difference between kWh and KWH?

There is no difference in the meaning of kWh or KWH. Both forms of writing kWh mean "kilo watt hours," and the format acceptable to most in the technical community is "kWh."AnswerThe correct symbol for kilowatt hour is kW.h.


What capacity of battery for 20kva ups 30 minutes backup time?

To determine the battery capacity needed for a 20 kVA UPS to provide 30 minutes of backup time, you first need to convert kVA to kW, assuming a power factor of 0.8, resulting in 16 kW. For 30 minutes of backup, you would calculate the energy requirement: 16 kW × 0.5 hours = 8 kWh. Therefore, you would need a battery capacity of at least 8 kWh, but it's advisable to consider additional capacity for efficiency losses and battery discharge characteristics, so a battery rated around 10 kWh would be recommended.


How to convert kva-kwh?

To convert from KVA (kilovoltamperes) to KWH (kilowatthours) first convert to KW (kilowatts) by multiplying by power factor. Power factor is the cosine of the phase angle between voltage and current. Then multiply by the number of hours that you run the load.


What is the fuel consumption of 5 kva generator?

if your generator fuel consumtion is 275g/kwh, then you multipli 5kva*.8=4kw. (4*275)/1000=1.1 liter per hour.


Why do energy companies use kWh for bills instead of joules?

Energy companies use kilowatt-hours (kWh) instead of joules because kWh is a more convenient and practical unit for measuring the amount of energy consumed by households and businesses. Joules are much smaller units, requiring large numbers for typical energy usage, whereas kWh provides a more manageable figure for billing purposes.


Working principle of trivector meter?

trivector meters are used to measure kVAh and also kVA of maximum demand.it has a kwh meter and reactive kvah meter in a case with special summator mounted between them.


What is fullform of kwh?

KWH