watts to va conversion 1

[jeffreyco]

hello! can you guys suggest any websites that provide conversion from watts to va?

i only managed to find one

http://haddow.albury.net.au/ups/VaWatts.html

but it is not complete (e.g. 250W to ? VA)

perhaps gurus could teach me some kind of formula... =)

Any suggestions or recommendations would be greatly appreciated. Thanks!

 

[josepablomir]

In any kind of load (load is the device draining power from an electrical circuit, for example a computer), the formulas are as follow:

Volts x Amps = Volt Amps (apparent power)
Volts x Amps x Power Factor = Watts (real power)

Power Factor is usually between 0.3 and 0.75 for computers and other electronic-type load.
For electronic-type load I am referring a PWM based power supply without 60 Hz input transformer (computers, routers, UPSs, etc.).

In the table your link points the Power Factor used to calculate the table is 0.7, which is a common assumption in computer systems (but only an assumption).

In case you want it, a formal definition of Power Factor could be: “ The cos of the shift angle between the voltage applied to a circuit and the current forced to circulate in it”.


Hope this help.
Regards,
_________________
Jose P. Mir
jpm@jpmir.net