Active PFC?

The

Non-PFC offers around 0.5~0.6 PF (Power Frequency), 40%~50% power lost.

they talk rubbish which doesn't inspire much confidence

Power factor isn't about efficiency, it is about the way the power supply draws current, which without PFC distorts the power waveform and presents a bad load to the generator.

You will not see any dollar savings with a PFC supply, it will use a bit more power, but it will present a cleaner load to the power grid.

Bill C

while.

computer?

In the UK if you had enough equipment to significantly lower your power factor you can (on the correct tarrif) install power factor correction & save money. (one PC won't do it)

Ok, so if there is no dollar savings in an Active PFC power supply, why is the manufacturer of the power supply talking about lost power? I don't understand the terminology.

Say for example that I have two power supplies. Each is rated at 360Watts. One is non-PFC and the second has Active PFC. According to what you said, they both still use the same amount of power? So the 40-50% power loss would mean that I can hook up fewer devices to a non-PFC power supply? Which would mean I could use a lower wattage Active PFC power supply to support the same number of devices that a non-PFC power supply would support? If that's right, then I could use a 216Watt Active PFC power supply to do the same job as a 360Watt non-PFC power supply ( assuming a 40% power loss on the power supply that's non-PFC )?

I hope the above is correct .... otherwise I'll just give up.

has

savings.

The one with poor power factor would draw more current, so you couldn't put as many on the same circuit, or, if large, you might need a circuit with greater capacity. The extra current drawn by the non-PFC supply doesn't do any work (it is like reactive current), so it doesn't add to the output power. The output power would be the same for both, but the non-PFC one would _appear_ to draw (say) 700 watts if you just looked at voltage and current.

PFC does increase efficiency of the electrical wiring a bit, since there is lower current, hence lower wiring losses.

Regards, Allen

I think you mean "Power Factor"

Not true, if we're talking power factor, the "lost" power is returned to the supply each half cycle. The consumer won't be paying for it, if his meter is properly designed.

Active power factor correction only makes much sense to supply companies, who want their voltages and currents as nearly in phase as possible. Unless the load is quite large, the extra losses in wiring won't be more than a few cents a month.

As do most companies playing on the susceptibilities of the average non-technical punter.

I suspect that whoever wrote that simply doesn't understand what they are talking about. A power supply with poor power factor doesn't "lose" power, but it does draw almost all its power near the peak of the AC waveform. A PFC corrected supply draws current throughout the AC waveform. Ideally, current would be proportional to voltage.

The 360 watt spec is the maximum output power. With 360 W out, the input power is somewhat higher - but probably about the same for both designs. If you reduce the load to 180 W, the input power will also drop in half (or nearly so). The supply doesn't "use" much power internally.

No, both have the same output rating. And the "40-50% power loss" is nonsense.

Dave