Practical example of power factor
Posted: Wed May 02, 2012 9:02 pm
(This doesn't directly involve PC PSUs, but this seems the most reasonable place to post it.)
I've been using a borrowed Adcom GFA-555 for a couple weeks & watching it through my Kill-a-Watt. This amp has a pretty sizable power supply, and the KaW has shown some interesting data.
The 555 draws about 45W/70VA idling (a bit more when it's hot). But it sucks a lot more to charge its capacitors when first powered up. I've seen this hit between 275-375W; it's very inconsistent because the KaW samples too slowly. Tonight I looked at power-on VA for the first time. 830! The power factor goes way out of whack with that 1st second's hugely capacitive load.
I've been using a borrowed Adcom GFA-555 for a couple weeks & watching it through my Kill-a-Watt. This amp has a pretty sizable power supply, and the KaW has shown some interesting data.
The 555 draws about 45W/70VA idling (a bit more when it's hot). But it sucks a lot more to charge its capacitors when first powered up. I've seen this hit between 275-375W; it's very inconsistent because the KaW samples too slowly. Tonight I looked at power-on VA for the first time. 830! The power factor goes way out of whack with that 1st second's hugely capacitive load.