Re: UPS va/watt ratings
So then the second number of the UPS rating is the maximum load that the UPS will supply (360 watts) and the first number is the total power that the UPS consumes including the load served by the UPS(600va). Is that correct?
Not exactly. Both the 600 va and 360 w are output ratings, in other words, the load that the UPS will handle.
Most UPS units are designed to operate electronic equipment that usually includes a switch-mode power supply.
The switch-mode power supply, when viewed as a load, is neither capacitive nor inductive, but non-linear. A switch-mode power supply draws current in short pulses that are not in phase with the line voltage.
This can cause the Power Factor to be less than 100% in the same way that an inductive (motor) load can.
The volt-amps (product of RMS volts x RMS amps) is considerable higher than the watts (real power consumed), and thus the Power Factor is less than 100%, typically around 60 to 70%.
Many UPS manufacturers assume the load Power Factor to be 60% for lower rated units, and 80% for their larger rated units.
600 va X .6 = 360 watts
This is a difficult subject to try to explain in a forum such as this. It takes my students a week to understand it.
Ed