Re: What kind of UPS do Europeans use? My modified sq wave UPS + PFC'ed load = CRASH !

phil-news-nospam_at_ipal.net
Date: 07/08/04 

Date: 8 Jul 2004 16:37:33 GMT

In alt.engineering.electrical AC/DCdude17 <dude17@sacremovebeemail.com> wrote:

| An example of power factor corrected PSU:
| http://www.savastore.com/products/product.asp?catalog_name=Savastore&product_id=10262447&pid=44

Do you have any schematics or design theory?

| The passive PFC on a power supply like the one linked above is the same
| type as the one in my ballast. Since computer power supplies in the US
| typically don't have a PFC, we're fine, but how do Europeans get their
| PFC equipped computers to get along with their UPS? I searched "PFC
| UPS" on Google and looks like I'm not the first one to have issues with
| a UPS interecting badly with a PFC power supply.

I would have thought that a proper power factor corrected load would be
indistinguishable from a linear resistive load. Maybe what they are
talking about is just the phase angle, rather than harmonics? Maybe
this kind of PFC is actually making harmonics worse?

| My UPS shares the transformer between inverter operation and charging.
| It's a steel core transformer with center tapped secondary. When
| operating on battery, the center tap on secondary is tied to one of the
| battery terminals and the MOSFETs switch the other terminals back and
| forth between the two taps on the sides. A relatively common design.

And that's not producing any backfeed? 

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