Aspire PSU with bad caps

[Rulycat]

Re: Aspire PSU with bad caps

Aren't you just wasting money on electricity bills through using such an inefficient POS though?

[BigTroll]

Re: Aspire PSU with bad caps

Aren't you just wasting money on electricity bills through using such an inefficient POS though?

Good point luckily our electricity bill is subsidized so its only like $50 a month.

[Rulycat]

Re: Aspire PSU with bad caps

Unfortunately they are anything but subsidised here. Efficiency is worth its weight in gold!

[BigTroll]

Re: Aspire PSU with bad caps

yeah well my main rig has that pc power and cooling supply its pretty efficient with active pfc.

[tom66]

Re: Aspire PSU with bad caps

UGH! Sorry, I hate when people say active PFC is more efficient.

It isn't! If anything it makes it LESS efficient. It's like adding 5-10% of losses. It's not a free lunch by any means. All it does is shape the input current to give the power supply a high power factor. You as an electrical supplier's customer do not pay a penny more if your PSU uses power at 0.5 PF or 0.99 PF.

The only reason it is used is a) it makes a PSU cheaper for high output power (smaller main capacitors and relaxed primary design) and b) it's a legal requirement in the EU above about 75W (though you can get away with passive PFC up to 200W.)

[BigTroll]

Re: Aspire PSU with bad caps

UGH! Sorry, I hate when people say active PFC is more efficient.

It isn't! If anything it makes it LESS efficient. It's like adding 5-10% of losses. It's not a free lunch by any means. All it does is shape the input current to give the power supply a high power factor. You as an electrical supplier's customer do not pay a penny more if your PSU uses power at 0.5 PF or 0.99 PF.

The only reason it is used is a) it makes a PSU cheaper for high output power (smaller main capacitors and relaxed primary design) and b) it's a legal requirement in the EU above about 75W (though you can get away with passive PFC up to 200W.)

Thats quite interested I never knew that, I really appreciate that I will use it to TROLL my co-workers tomorrow.

[Behemot]

Re: Aspire PSU with bad caps

UGH! Sorry, I hate when people say active PFC is more efficient.

It isn't! If anything it makes it LESS efficient. It's like adding 5-10% of losses. It's not a free lunch by any means. All it does is shape the input current to give the power supply a high power factor. You as an electrical supplier's customer do not pay a penny more if your PSU uses power at 0.5 PF or 0.99 PF.

The only reason it is used is a) it makes a PSU cheaper for high output power (smaller main capacitors and relaxed primary design) and b) it's a legal requirement in the EU above about 75W (though you can get away with passive PFC up to 200W.)

Active is not that much like 5-10 % I think. Quite interesting is ppl still talk about PFC only, but they do not consider loses in the network (when higher current flows before and after the PSU, there are always loses). Not mentioning the necesity of higher-dimensed brakers and so on.

[tom66]

Re: Aspire PSU with bad caps

Active is not that much like 5-10 % I think. Quite interesting is ppl still talk about PFC only, but they do not consider loses in the network (when higher current flows before and after the PSU, there are always loses). Not mentioning the necesity of higher-dimensed brakers and so on.

Typical PFC boost stage efficiency is 88-95%, so 5-12% losses.

- https://cdn.badcaps-static.com/pdfs/...389b97635a.pdf (page 11)
-

Typical losses in the UK distribution network are less than 2%, and that's for hundreds of km of wire. Your home typically has about 1-2 ohms of resistance in the cabling, which makes hardly any difference (if you've got an 500VA reactive load, it's about 9W of losses, or 1.8%.)

Don't know about your house, but we have (at home) 32A breakers on the upper and lower sockets. The computer uses less than an amp typically, but the washing machine and tumble drier use about 15A total. Which matters most to the breaker?

PFC is good for the electric company, but costs the consumer more.

[Behemot]

Re: Aspire PSU with bad caps

To the braker matters everything. Typically in average house/flat ppl have at least 1 PC, 1 display, 1 TV, 1 satellite reciever/set-top box running. Than you turn on oven and cooker and when you also want to turn on electric kettle (is there some word for that? ), suddenly breaker goes off. Oh whatafuk? Is it those SMPS-build electronic appliances take 3-5 extra amperes more than it could just because they have no/passive PFC?

I guess you use superconductors than, our distrubiton losses are arround 10 % (that is only oficial statement I found in some electricity usage overview, but it is many years old number).

I am sorry, but I do not believe that PFC efficiency numbers. Or more specifically, I do not believe the number is so big in computer PSU PFC circuits. Half of the better todays PSUs on consumer market has efficiency of 85-90 % total. So if the PFC had your 88-95 % efficiency than it would mean from 66 % up to 100 % wasted power is wasted by the PFC only! This is not true obviously.

Our major electric producer is state-owned company so we indirectly pay new power stations anyway. So I rather see lower wasted power (cause power station-wise, reactive load is wasted power). Sorry, but it's your problem you privatised your energetic companies (or never had any, don't know), it is one of the things which should belong to state under every circuimstances.

[mariushm]

Re: Aspire PSU with bad caps

Power factor correction is indeed something more beneficial to power companies, as the power company loses money due to losses in electrical network due to low power factor.

However, there are also some benefits due to the higher voltage the power supplies have when using Active PFC.. lower losses in the transformer and inductors among other things.

So the minor loss due to pfc boost circuitry is often offset by the benefits.

There's a couple of videos which explain nicely the power factor in a surprising way, by explaining what impedance is:

http://www.youtube.com/watch?v=xyMH8wKK-Ag
http://www.youtube.com/watch?v=tZBMfDvWF4U

I quite enjoyed learning about impedance from these, and the power factor discussion was the cherry on the cake.

[tom66]

Re: Aspire PSU with bad caps

Hmm, I have never tripped a breaker myself when using normal loads. Trip curves - you can draw about 64A from a 32A breaker (type C) for about 2 minutes IIRC... and 32A for around 2 hours. If you breaker is tripping too early, it needs to be changed.

PFC can be efficient, but the point is it contributes only losses to the customer. It can be beneficial for the power company. Which MAY be beneficial for the consumer, but there are a lot of non-PFC loads still out there, and as I said, there's not much lost, so it just leads to greater usage.

Reactive loads aren't lost to the power company. They just cost more to transmit. But it's not like 500VA with 250W real power costs twice as much to generate, it's maybe a couple of percent (with cut-throat margins, it can mean a lot to the power company.)

The 2% statistic came from a science textbook. I'll try and get a source.