APC UPS on PFC Type Power Supply

[Anonymous user]

Are APC Back-ups product compatible for PFC type power supply? I heard from some friends that the APS back-ups
were having problem with their DELL and IBM desktops which are using PFC power supply.

Thanks in advance

[EZ_Button_apc]

There is an APC Kbase with regards to PFC Type Power Supplies.

http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=8883

It's not that APC back-ups aren't supported, you just need to size appropriatly. As the Kbase states, PFC power supplies will show a high amount of inrush current and cause potential overload situations for undersized back-ups.

[Anonymous user]

Taking the inrush current issue apart, it seems there are some issues with UPSes that outputs a 220-240 Stepped Sinewave. Something regarding voltage peaks on the bulk capacitor of the power supply. You can read it at:

On the topic below it seems some information are not very accurate, but some stuff are cleared on the Badcaps forum:

http://www.jonnyguru.com/forums/showthread.php?t=3964

Things are more throughly discussed on the topic below (to see the pictures posted there you need to be a registered user):

http://www.badcaps.net/forum/showthread.php?t=5181

I myself have an APC Backup BE600-LM (made for the latin american market), it outputs 115-120V Stepped Sinewave and I've been using it for about 4 months on a Zalman ZM460B-APS and haven't noticed anything wrong with it yet, apart from a buzzing noise coming out from the PSU while on battery.

Message was edited by: rau

[Anonymous user · Accepted solution]

It depends on the power supply and the UPS.

For example, my 32" LCD has an active PFC power supply and it works fine on an APC BK650, a modified squarewave inverter UPS.

A two lamp F32T8 fluorescent fixture with active PFC ballast as well as many magnetic ballast fixtures go haywire when powered by a low-frequency switcher(a topology used on most UPSs) type and they flicker beyond practical use.

However, these same fixtures work better on high-frequency switcher topology modified squarewave inverter(commonly used on 12v to 115v inverters sold for vehicle use) as the inverter vs load interaction is different for some reason.

A non-PFC CFL works perfectly fine on modified squarewave APC UPS.

An active PFC in power supply is a measure intended to satisfy the environmental groups and the utility company and sometimes, it manifests itself as an unfortunate expense to the end user as having to employ a sinewave inverter UPS should it be incompatible with modified squarewave type.

Message was edited by: KVAr