How much power used when device is Off.

I hope you all can explain this to me.

Let's assume we have an AC adapter with only a small number of parts, a step-down transformer and 1 to 4 diodes.

Let's assume that the primary of the adpater uses 0.1 amps at 120 volts. (I don't think it matters for the sake of this question how much the device itself uses. We can pretend that there are no losses and it has an output of 1 amp at 12 volts, and powers a device that uses the full amp. Or that the device uses less than that.)

So in this case when the device is on, it's consuming 12 watts from the power company. The primary of the AC adapter is using 12 watts.

Roughly, with an adapter of typical, simple, only 5 parts, design, how much in watts would the adapter use if the device were turned off, that is, if the secondary circuit of the adapter were open? The primary circuit would still be closed. The inductive impedance of the primary winding would go up -- it took me years to figure that out -- but I have no idea how much.

2) Yesterday, someone gave me a broken AC adapter used to power a Westell DSL modem. I broke it open and instead of the 5 or 6 parts such things used to have, this one had about 25 parts, including a small transformer and what looked like another winding on a metal core. Plus 3 big caps (one or more filter caps), I need more light and better glasses to count the diodes, one transistor, and something looking like a little glass fuse but with a white sandy body.

Something this complicated must be smarter than earlier adapters. Does that mean it uses less current when the device intended to be powered is Off? Any idea how much a 25-part adapter like this uses when the devices is Off, assuming when it's On it uses 12 watts?

Thanks.

Reply to
mm
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"mm"

** The number is not fixed - like most things, it varies.

The range is from about 0.5 watt to 3 watts for a 12 watt adaptor.

Some fuckwits think this matters and have passed laws banning the sale of adaptors that use more than 0.75 watts or so when off load.

DAMN WANKERS !!!

Like YOU !!!

... Phil

Reply to
Phil Allison

There's a market inefficiency. An adapter that wastes 3 watts when left plugged in would cost about $4.50 per year to run under Powersmart residential rates in NSW. But purchasers are unlikely to factor that into their decision to buy, which will probably be determined by sticker price.

To address this market ineffeciency, a regulator has two options - either ban such profligate power consumption, or require clear labelling of the power consumption implications. Since it is highly probable that a less power hungry adaptor can be manufactured for less additional cost than the annual cost of the excess power consumption, it makes sense to take the route that dictates a maximum unloaded power consumption.

Sylvia.

Reply to
Sylvia Else

"Stupider than Anyone a Else Alive"

** No there is not.

** The energy is not wasted.

** Which does not exist.

** Nothing of the sort is happening.

Profligate power consumption is not due to tiny adaptors and a few watts.

Large appliances like water heaters, air conditioners and domestic halogen lighting are the main culprits.

Fuckwits like Sylvia can never see the wood for the trees.

Cos her ugly head is made entirely of rotten wood.

.... Phil

Reply to
Phil Allison

You seem to be assuming that the intervention is about energy consumption. Well, maybe it is. But the intervention can be justified on purely economic grounds. The comsumers* are better off as a result of the intervention, even if they don't realise it.

Sylvia

[*] Except for the smally minority who unplug/switch off their adapters.
Reply to
Sylvia Else

"Stupider than Anyone a Else Alive"

** No there is not.

** The energy is not wasted.

** Which does not exist.

** Nothing of the sort is happening.

Profligate power consumption is not due to tiny adaptors and a few watts.

Large appliances like water heaters, air conditioners and domestic halogen lighting are the main culprits.

Fuckwits like Sylvia can never see the wood for the trees.

Cos her ugly head is made entirely of rotten wood.

.... Phil

Reply to
Phil Allison

"mm"

** The only thing that consumes power in standby mode is the iron transformer.

Some heat goes into in the wire of the primary and the rest in the iron core.

So it gets a tad warm to the touch.

** Most recent design switch mode adaptors virtually shut down when there is no load on the output.

Older ones do not do this and run warm, like the iron tranny ones.

Nothing is a simple as you might like.

... Phil

Reply to
Phil Allison

While Phil and Sylvia (who is Sylvia?) duke it out...

The primary current drawn by an "off" power supply is (I believe) mostly reactive, so (I assume) the watt-hour meter doesn't see it. (I still haven't called PSE to confirm this.) Of course, if the supply runs warm even when unloaded, it's definitely wasting energy.

There are market forces moving manufacturers in the direction of highly efficient supplies -- specifically, international sales. Products are increasingly supplied with small switching supplies that can work at 50 or

60 Hz, at 100 to 240 volts. Thus, only one supply is required, regardless of where the product is sold.

I'm a great believer in government intervention in markets, to make them do what they should be doing. But forcing companies to make efficient power supplies doesn't seem to be necessary, as they're doing it themselves.

California is considering a law that would phase in reduced TV power consumption. The problem is that this isn't easily done (particularly with plasma sets), and LCD manufacturers are switching to LED illumination, anyway.

Reply to
William Sommerwerck

Depends on the quality of the transformer. A properly designed and manufactured transformer can be very efficient. A cheap Chinese POS can be incredibly inefficient, more a room heater than a transformer.

Switching powersupply perhaps?

Cheaper to make. Can be more efficient.

Well, measure the power consumed and see what you get? That is what I'd start with.

Another test, limited, is to measure temperature rise. Start with a 'cold' unit, no load, and watch how the temperature rises when it is powered up. Any power consumed when unloaded will be converted to heat. Testing loaded efficiency is more difficult, but clearly not impossible to do with either a power in/power out ratio, or even a heat rise measurement loaded to unloaded.

Reply to
PeterD

We have electric heat. People tell us we should turn off our (incandesent) lamps whenever possible. "It's the green thing to do..." they say.

Clueless.

Reply to
PeterD

e of

s.

alogen

Hide quoted text -

The government knows what is best for you!

Just ask sylvia.

Reply to
sparky

Can you say "simple, cheap adapter"? Sure you can.

Reply to
William Sommerwerck

"William Sommerwanker"

** Completely irrelevant to the question which was about "power" and not VA.
** Absolute BOLLOCKS !!

Small AC adaptors are built to plug into a domestic power outlet - there are dozens of different kinds round the world.

So a different PHYSICAL design is therefore required for each part of the world.

formatting link

..... Phil

Reply to
Phil Allison

"PeterDope"

** The question was not about efficiency - it was about standby or "off - load " power consumption.

The transformers fitted to most AC adaptors are designed to do a given job while using the least amount of materials - PLUS must be completely safe to users in case of any kind of overload or internal failure.

The trannys that have become standard practice are finely tuned to these two requirements. Hence we see only E-core types with split bobbin construction with fireproof insulation around the insides of the core and/or a thermal fuse in the primary.

One sized to produce 12 watts of DC power will necessarily have a standby power draw of a watt or two - simply as a result of the iron core being fully magnetised all the time.

Regulations that require standby powers of 0.75 watts or less preclude to use of such designs - certainly if the output power is more than 6 watts.

BTW

The kind of adaptors that output AC volts are simply not included in the new regulations - since there exists no replacement for them.

.... Phil

Reply to
Phil Allison

"William Sommerwanker"

** The above congenital idiot does not even read the posts he replies to.

** Completely irrelevant to the question which was about "power" and not VA.
** Absolute BOLLOCKS !!

Small AC adaptors are built to plug into a domestic power outlet - there are dozens of different kinds round the world.

So a different PHYSICAL design is therefore required for each part of the world.

formatting link

..... Phil

Reply to
Phil Allison

You've apparently little experience with the *manufacturing* side of things. Otherwise, you would realize that you can

*easily* specify a different physical power plug attached to the *same* bit of electronics.

Indeed, some vendors now provide wall warts with interchangeable plugs (though they *install* just one -- whichever is appropriate for your region). The external disk drives I recently purchased went this route (I suspect I could even remove the "plug" if I spent 30 seconds tugging on it).

The 5V 1A wall wart that I rewired yesterday was a similar design: the PCB within mated to a specific plug style molded into the casing -- move the PCB to a different case and it is now suitable for ~220VAC operation.

IIRC, certain places in England have different outlets and within the same country/region (?). It is foolishly expensive to design different adapter electronics just to accommodate different plugs/voltages (my designs have used "universal power entry" since the mid 1980's -- the choice of "plug" being left to the power cord sold with the unit!)

Reply to
D Yuniskis

** My comment above still applies.

Either there is a different case and plug arrangement produced for each market or, in some cases, a plug adaptor is attached to the existing plug.

To comply with safety rules in most places, such plug adaptors must be permanently attached PLUS the combined contraption be not too likely to fall out of a wall socket.

** Fraid that is not safety approved in most places.

** Backs up my point - a different PHYSICAL design is needed for each market.

It is not possible to produce one design of "wall wart" adaptor and sell it world wide - which was the point at issue.

..... Phil

Reply to
Phil Allison

Yeah, and I am sure they sell pink ones and blue ones too! But that doesn't affect the DESIGN OF THE ELECTRONICS within (I suspect the *color* of the device does little to affect the power consumed! :> )

This is apparently not the case in the US. :>

Well, I have only designed products for 7 or 8 markets so I won't claim to be an expert here. I can talk with friends servicing european markets (lots of countries in a small geographical region) to see how their experiences have fared...

That won't affect the power consumption, heat radiated, etc. any more than the color would. The internal design of many of these units is the same. Certainly anything *I* have designed in the past 25 years. And, as William pointed out, I suspect that is becoming increasingly the case. It costs money to maintain different designs. To do the actual engineering. To stock the parts. To fabricate the product. To service it. Etc. Far cheaper to come up with *a* design and just slip the guts into a "locale specific" shell.

Reply to
D Yuniskis

"D Yuniskis"

** FUCK OFF !!!

YOU INSANE BLOODY YANK MORON

Reply to
Phil Allison

Go to a Costco -- or any other place that sells a Seagate "FreeAgent | Desk" UPC code 7 63649 01223 9, part number

9ZB2B8-571 (i.e., this is a real part, I am holding two of them in my hands right now)

The part number for the wall wart is WA-24E12. It is manufactured by "Asian Power Devices, Inc."

The wall wart is listed as "100 - 240VAC 50 - 60 Hz" with a "12V 3A" output. The "plug" clearly is a separate piece that slides onto the body of the wall wart. Not only is it NOT "permanently attached" but it has a "button" clearly labeled "PUSH" which, when pushed, allows the "plug" to be slid off of the wall wart. The force required to actuate this button is just a bit over 4 ounces (i.e., something an *infant* could manage).

Just to be sure we are all in agreement on what "permanently attached" means, my Webster's New World defines "permanent" to mean "lasting or intended to last indefinitely or for a relatively long time" -- something that I can alter within

*seconds* of opening the box and holding it in my hands I doubt would qualify as "indefinitely"; nor even "a relatively long time" (unless measured against the half-life of some of the elements having atomic numbers in excess of 100!)

Likewise, the best definition I can find for "attach" would be "to fasten by tying, etc.". So, I guess "sliding onto" the wall wart would be consistent with "attachment". I guess we just have vastly different ideas of what "permanent" means!

There should be enough INDEPENDANTLY VERIFIABLE information in my post (unlike your random, unsubstantiated rants) for others to verify this and decide who speaks truly. :>

Or, perhaps Seagate is selling these things despite YOUR apparent prohibition on their use/sale?

(sigh) Yet another USENET wacko. Welcome to my killfile! Isn't it time for your meds? Maybe *past* time?? ;-)

(OK, now you can go and rant some more. I -- and anyone else who has been smart enough to add you to their killfile already -- won't be bothered with your meaningless posts.)

Reply to
D Yuniskis

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