Can anyone verify the power factor on one of these? I'm wondering if the one I tested is defective, or if they're all crap with a PF of 0.93.
I always struggle with pf vs efficiency
These are supposed to be 93% efficient platinum.
So what are they?
I know the 2880 IBM psu is gold at best
Th 2980 IBM psu is a platinum.
Both my test on them were done with stock fans and with my fan mods
Stock screamers use 60 watts, my mods use 25 watts.
So does pf = eff?
No 2 different things although PF does impact efficiency.
Power Factor is how well the load compares to a purely resistive load which is a PF of 1.0. A purely resistive load has current draw exactly in-phase with the voltage.
Toss in capacitance or inductance eg. the cap inputs to a switching supply or a filter choke and current then either leads or lags behind voltage. Normally not an issue for users but when you start running heavy loads like several 10's of kw -- then the power grid starts to complain because the out of phase current draw will start to become much higher that what the average current reflects.
PF can either be passively or actively corrected in a PSU. Passive correction works at the expense of overall efficiency, active control is more efficient but costs more to implement.
EDIT: All about PF
http://powerelectronics.com/power-electronics-systems/back-basics-power-factor-and-why-we-correct-it