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Active PFC What benifit do I get besides getting to pay more for my UPS?

Last response: in Components
July 30, 2011 12:06:56 PM

No one seems to be addressing this issue.

From my very limited understanding of this subject if you have an active PFC power supply you need a pure sine wave UPS to actually provide power interruption protection.

Those are quite a bit more expensive.

Is a one of the main benefits of active PFC more stable voltages to the computer system, when voltages fluctuate at the wall?

If that is case maybe it would be important to decide before buying a power supply if you are going to use a UPS or not.

If you are then you do not need this benefit, as the ups will stabilize the voltages before sending power to your PC.

a c 694 ) Power supply
July 30, 2011 2:09:28 PM

Not only does it give you better voltage regulation but also much higher efficiency!
Quality of voltage regulation in budget consumer UPS's has been disputed for a long time.
July 30, 2011 4:15:45 PM

we already have a standard for PSU efficiency.
Certified 80 PLUS bronze up to platinum.
is not good enough now?
it needs to be Active PFC too?

please define much higher.
because what I have read online says you won't see a difference in your electricity bill unless you are a large business with a hundred computers.

So can I buy any UPS I want for these active PFC units?

a c 694 ) Power supply
July 30, 2011 6:35:36 PM

Agree with the statement on the electricity bill since even with the large PSU's in gaming rigs today it is just a small part of the electricity consumed at a given home today! All quality PC PSU's today are made with active PFC to reach the 80+std's. Borrowed from Wikipedia
"For example, SMPS with passive PFC can achieve power factor of about 0.7–0.75, SMPS with active PFC, up to 0.99 power factor, while a SMPS without any power factor correction has a power factor of only about 0.55–0.65.[15]"
"With the rising cost of energy and concerns over the efficient delivery of power, active PFC has become more common in consumer electronics.[16] Current Energy Star guidelines for computers (ENERGY STAR® Program Requirements for Computers Version 5.0) call for a power factor of ≥ 0.9 at 100% of rated output in the PC's power supply. According to a white paper authored by Intel and the U.S. Environmental Protection Agency‎, PCs with internal power supplies will require the use of active power factor correction to meet the ENERGY STAR® 5.0 Program Requirements for Computers.[17]
In Europe, IEC 555-2 requires power factor correction be incorporated into consumer products.[18]"

Full article
On the UPS side I have little knowledge since I always buy quality PSU's with internal protection to protect my other components, never had data corruption or lost other hardware during power outs or lightning storms which is plenty of in south Florida.
July 30, 2011 7:36:38 PM

I guess i did not define problems.

here are some quotes regarding problems with UPS and Active PFC PSU's
if you want more just google

"UPS problems with active PFC power supplies"
or something similar

Both. I just spoke with both Silverstone and APC. Silverstone is going to get back to me on this question, but APC was pretty clear -- they strongly felt that PFC power supplies should use true sine wave UPSs. They told me that the reason for this was because PFC power supplies require a much faster changeover time when the battery kicks in, and that due to the design of stepped sine wave UPSs, they were not always fast enough to satisfy the power supply. This could lead to the PSU *****shutting down when the battery tried to kick in.******The guy I spoke with said that the stepped sine wave wouldn't "damage" the PSU, but that it simply might not work, and that if it DID work, it might not "always" work. Apparently it depends on the specific power supply.

I recently bought an APC BACK-UPS RS 1500VA 230V. After I had bought it i found out that there is a rumor in the Internet that this series of UPS is not compatible with PSUs that have Active PFC.
Is that so ?
Did anyone ever used this UPS with a UPS that was Active PFC ?

You just need to find the UPS models that output a true sine waveform. The majority of the household ones are simulated sine - and that caused a problem with my Enermax Infiniti. It would cause the overload to trigger when first turning the PC on, even though there was no overload.

It still worked, except for the occasional overload trip on startup, but I can't imagine it would be good for the PSU.

"Have an APC RS 1500, which I'm fairly certain is a simulated sine wave (if it wasn't ungodly expensive it's probably a simulated sine"

July 30, 2011 8:08:06 PM

All quality PC PSU made today use active PFC?

So any PSU that does not say Active PFC in its name or description is not a quality PSU?

Best solution

a c 271 ) Power supply
July 30, 2011 8:22:59 PM

Active PFC isnt really meant to benefit the consumer, thats not its primary purpose.

What it does do is save the power companies significant amounts of money, in the US consumers are only billed for real power used not complex power, active PFC makes the computer look like a simple toaster that is only using real power which lessens the load on the power lines and reduces transmission losses which saves the power company quite a bit of money.

The way Active PFC is implemented in modern PSUs has the advantage of providing universal input voltage capability so that the same PSU can be sold all over the world and wont need the little voltage switch for the voltage doubler circuit for North America.

Active PFC doesnt make a PSU more efficient, thats a miss conception caused by the fact that very few high efficiency units have APFC and all high efficiency units do. Active PFC actually consumes a bit of power BUT it boosts the voltages inside the PSU to a higher level than the passive circuits do so the other circuits in the PSU are more efficient, again this isnt because of the APFC its just a side effect of how they chose to implement it.
July 31, 2011 3:43:52 PM

Best answer selected by alohascott.
a b ) Power supply
July 31, 2011 6:09:34 PM

This topic has been closed by Mousemonkey