How much power used when device is Off.
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From: Phil Allison on 26 Dec 2009 06:51 "Stupider than Anyone a Else Alive" > There's a market inefficiency. ** No there is not. > An adapter that wastes 3 watts ** The energy is not wasted. > To address this market ineffeciency, ** Which does not exist. > either ban such profligate power consumption, ** 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
From: Phil Allison on 26 Dec 2009 08:17 "mm" > > Let's assume we have an AC adapter with only a small number of parts, > a step-down transformer and 1 to 4 diodes. ** 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. > 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? ** 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
From: PeterD on 26 Dec 2009 09:17 On Sat, 26 Dec 2009 04:12:58 -0500, mm <NOPSAMmm2005(a)bigfoot.com> wrote: >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, 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. >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. Switching powersupply perhaps? > >Something this complicated must be smarter than earlier adapters. Cheaper to make. Can be more efficient. >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? 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. > >Thanks.
From: PeterD on 26 Dec 2009 09:19 On Sat, 26 Dec 2009 21:06:42 +1100, "Phil Allison" <phil_a(a)tpg.com.au> wrote: > >"mm" >> >> 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. > > >** 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 > > <g> 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.
From: William Sommerwerck on 26 Dec 2009 08:29
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. |