Active PFC PSU requires A sine wave generatin UPS ???

[Anonymous user]

my sys config :: Quad core , Intel Classic seriesMB, 2GB ram,250GB SATA HD , XFX 9800 GTX card....and my UPS is a old model APC 500VA one

I'm gna get a Cooler Master Real power Modular 600W SMPS ...
But i found in some posts that it requires a real sine way generating UPS ...But those posts were posted in 2004-06...is it still incompatible ??? or should I go for a passive PFC???

[BillP]

Hi:

You are correct in the fact that active PFC power supplies often do not respond well to a stepped approximation to a sine wave, as our Smart-UPS SC's and Back-UPS's output.

See the following knowledge base for details on the technical aspect: http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=8883

A passive PFC power supply may give you better results, OR if you prefer, you can purchase a UPS that does output a pure sine wave. This includes our Smart-UPS "SUA" models; i.e. SUA750, SUA1000, SUA1500. Feel free to trade in an existing UPS for a discount towards one of these.

Thanks

[Anonymous user]

I have an APC BN1250 UPS. My computer has an Antec EA-500D P/S which does have power factor correction.
During self-test, when the UPS switches to battery my computer shuts down then restarts after a few seconds. All other equipment on the battery backup outlets (cbl modem, router, computer display, hardware firewall do not shut off during self-test.
The ups output is advertised as a "stepped approximation to a sine wave." Using a scope, utility power is a perfect sine wave. When the ups is on battery power it is a 50% duty cycle square wave - not even close to a stepped sine wave. With the computer off while on battery if I start the computer it does boot and runs with no errors which confirms that the computer p/s will run with the ups on battery. My first guess is the Antec P/S can't handle the UPS transition time (advertised as 6-8ms) from utility to battery backup.
Any comments are welcome.

[BillP · Accepted solution]

Good day Frank,

Since you have mentioned that your computer booted up and worked fine while your UPS is on battery then your analysis is right. One reason why the computer dropped is due to the transfer time that our BackUPS has. The time to switch from online to on battery is too long that the power supply has already detected it as power loss.

For a much more shorter runtime, i.e. 2-4ms our SmartUPS (SMT/SMX/SUA) unit should be able to help you out. If you do need 0ms transfer time that you need to get the Smart-UPS Online UPS (SURTA/SURT/SURTD).