Google Offers a Million Bucks For a Better Inverter

On 25 Jul 2014 11:56:13 GMT, Jasen Betts Gave us:

All ahead astern, Cap'n!

and

for

220V

is

50

So start from any PC and swap out the power supply with one that runs from

48 V (yes they are available). And you are set to go.

?-)

Sounds like total hooey to me. A great deal of added complexity and losses for no benefit (except for skinning ignorant buyers).

And have you seen the reviews on such, rather miserable.

?-)

over

OK, i will check on it for USA markets.

Haven't heard of them yet. I will check this also.

Probably. Be damn expensive though. Then again so could GE of Schneider (or is it Cooper) (or one of its subsidiaries).

?-)

instantaneous

loads..."

Sorry, no sale. Think it through more thoroughly with numbers the next time.

?-)

On Fri, 25 Jul 2014 22:58:16 +1000, Sylvia Else wrote:

instantaneous

power

sine

Nah, with pure RLC loads nothing is that hard except for resonances. You need diodes to get really bad loads.

OK. I started the simulation. It is really slow, about 30 ns steps for a

1 second simulation. Here is the .asc file:

Version 4 SHEET 1 880 680 WIRE -80 -32 -128 -32 WIRE 112 -32 -80 -32 WIRE 240 -32 112 -32 WIRE 112 48 112 -32 WIRE 240 48 240 -32 WIRE 112 128 112 112 WIRE 368 128 112 128 WIRE 448 128 368 128 WIRE -80 144 -80 -32 WIRE 368 160 368 128 WIRE 448 160 448 128 WIRE 240 224 240 112 WIRE 304 224 240 224 WIRE 112 256 112 128 WIRE 240 256 240 224 WIRE 304 256 304 224 WIRE 368 256 368 224 WIRE 368 256 304 256 WIRE 448 256 448 240 WIRE 448 256 368 256 WIRE -80 400 -80 224 WIRE -80 400 -128 400 WIRE 112 400 112 320 WIRE 112 400 -80 400 WIRE 240 400 240 320 WIRE 240 400 112 400 WIRE 352 400 240 400 WIRE 352 512 352 480 FLAG -128 -32 1 FLAG -128 400 2 FLAG 352 512 0 SYMBOL diode 96 48 R0 WINDOW 3 118 64 Right 2 SYMATTR InstName D1 SYMATTR Value MUR460 SYMBOL diode 224 256 R0 SYMATTR InstName D2 SYMATTR Value MUR460 SYMBOL diode 256 112 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D3 SYMATTR Value MUR460 SYMBOL diode 128 320 R180 WINDOW 0 24 64 Left 2 WINDOW 3 24 0 Left 2 SYMATTR InstName D4 SYMATTR Value MUR460 SYMBOL cap 352 160 R0 SYMATTR InstName C1 SYMATTR Value .05 SYMATTR SpiceLine V=600 Irms=10 Rser=.1 SYMBOL res 432 144 R0 SYMATTR InstName R1 SYMATTR Value 60 SYMBOL voltage -80 128 R0 WINDOW 123 24 124 Left 2 WINDOW 39 0 0 Left 2 SYMATTR InstName V1 SYMATTR Value SINE(0 240 60) SYMATTR Value2 AC 240 SYMBOL res 336 384 R0 SYMATTR InstName R2 SYMATTR Value 1G TEXT -164 462 Left 2 !.tran 1

?-)

Yep. There is also the need for some space for connections.

?-)

Well, yes. It's exactly a circuit that is parallel resonant at the fundamental frequency that I was thinking of.

Of course, it's plain silly to design a mains powered device like that, but in the context of a competition with specified limits on inverter behaviour, one has to assume the worst. I think it illustrates that the specifications haven't been sufficiently thought through.

Sylvia.

You could still buy microwave ovens with line frequency doublers in them. a few years ago although switchers were becoming more popular (they call it an inverter)

--
umop apisdn 


--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

Much depends of the construction of the house and the climatic conditions.

A flimsy wooden house with no thermal insulation will heat up the inside walls quite quickly on a sunny day. The air conditioning will have to cool down the fresh air for breathing and in addition also the heat entering through walls and windows.

On a cloudy day, you just have to cool the air intake.

In a well insulated house with double/triple windows, you just have to cool the air intake regardless if it is sunny or cloudy.

In dry conditions, say dew point at 10-15 C, the night time temperature can be well below 20 C, so any massive stone, brick or concrete building will even out much of the temperature variations, so indoor temperatures can be comfortable even without air conditioning. Alternatively, dump the day time heat into water and get rid of it during the night.

Of course, the situation gets ugly in humid climate, were the night time temperature remains high, but then, pay attention to the heat entering the building through walls and windows. In this case, you should know how much fresh (hot) air needs to be cooled, in order to exchange indoor air volume, say once each hour.

Even in this case, you could take the heat extracted from cooling the input air to a heat exchanger in the exhaust air blowout tube to transfer the extra heat into 20-25 C exhaust air instead of 30-40 C outdoor air and save some electricity.

As far as it goes, that's a correct reading. Notice that I did not say that appliances designed for AC mains power should be operated directly from a DC supply; quite the opposite - design the gadgets for the supply.

In Google's scenario, nothing electrical is being replaced. They want something to provide electricity where there is no supply at present, so the users will have no appliances in use for which adaptors or adaptation would be required.

I rather thought it could be assumed that anyone designing an appliance for a particular form of power supply, would actually design it for safety and efficiency.

[...]

450 is 'high' compared with 0.5 but 'low' compared with 1000. Google seem to be using the sort of specification that might be appropriate for an inverter feeding power into an existing mains grid, but that isn't the scenario they describe as the basis of their idea.

They could probably explain just what it is about their 12v DC appliances that they don't like. Sounds like another useful project for someone with oodles of cash to pay for.

Perhaps that's part of what Google should be funding as a competition; design a domestic electrical system and appliances to operate directly off the DC power supplied by photo-voltaic cells and electrical accumulators. Safety should of course be part of the specification.

The standardisation of "USB charging" for small appliances shows that 5 volts and 2 amps is perfectly adequate for many purposes. Fans TVs computers and fridges probably work better at something in the 10 to 20 volt range; sewing machines vacuum cleaners washing machines and the like may be best at 100+ volts.

Off-grid use of electricity for space heating or cooling doesn't seem sensible, but good building design obviates the need.

--
-- ^^^^^^^^^^ 
--  Whiskers  
-- ~~~~~~~~~~

Really? Outside temperature is a function of the home's construction? Wow! Talk about global warming!

So don't do that, dummy!

Ah, you have *perfect* insulation. Good theory. Air intake is much of the problem on hot, humid, days (~100/yr here).

So double-pane windows have infinite R? I have a house full of them that are somewhat less (and the e-bills to show it).

So you admit that your plan makes no sense.

Nighttime lows of 20C are of no help when the daytime temps are 35C and muggy.

More goal post movement...

There are ways to save electricity though the don't help your case for solar panels one little bit.

One guess, the equivalent weight 12v DC applicances are underpowered vs. their 120v AC cousins, and the equivalent power 12v DC appliances are significantly heavier than their 120v AC cousins.

The reason is simple ohms law.

Take a 1200 watt hair dryer. At 120v it needs to draw 10 amps to dissipate 1200 watts. 10 amps is managable with reasonable weight wiring.

A 12v hair dryer, however, to dissipate 1200 watts, must draw 100 amps. The wiring necessary to safely draw 100 amps without overheating the wires due to parasitic resistances is significantly larger (i.e., think of the size of the main battery cables under the hood (bonnet for those in the UK) of your car).

No one is likely to want to use a 12v hairdryer with 1 or 0 AWG wiring attached. Not to mention that the dryer itself will be heavier due to larger internal wires to handle a 100 amp draw. So the end result is that something like a 12v hairdryer is likely only 300 watts (still a draw of 25 amps) or less, meaning it simply does not work as well as its higher voltage cousins.

I bought one a few months ago for experiments with plasma.. I think it cost $50. Half wave doubler, same as it ever was.

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward" 
speff@interlog.com             Info for manufacturers: http://www.trexon.com 
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

Low power domestic appliances would of course run nicely from say 12 V, however, any high power loads such as electric stoves etc. would still need much higher voltage AC or DC feed su7ch as 380 Vdc. .

It would make sense in _new_ buildings to add sockets for small loads at 12/24/48/60 Vdc. For high power fixed loads use some suitable AC or DC voltage.

The transition could be gradual, as new houses are built. The heavy loads would be fixed to the building, but for small loads, problems will occur, when people move from old house to new house or vice versa. In this case adapters can be used.

All could be usable, 12 V is common in customer products, 24 V in industrial applications and 48/60 V in telco applications.

Perhaps +/-12 V so both 12 V or 24 V equipment can be used, thus eliminating a huge number of wall warts.

But in addition to this, you will need some high voltage high current feeds.

450 Vdc is by definition low voltage, both in the USA (limit 600 V) and internationally IEC 1000 Vac or 1500 Vdc.

However, I would not like to use 450 Vdc panel strings on my roof, in very hostile environment, rain, heat, snow, ice, sand, bird droppings, UV radiation etc.

"To be eligible to enter the Contest, you must be: ... (2) not a resident o f Italy, Brazil, Quebec, Cuba, Iran, Syria, North Korea, or Sudan? (3) not a person or entity under U.S. export controls or sanctions?..."

Low end junk ...and that's Canada right? ( surprised they even have uwave ovens available )

Well I wasn't looking forward to drilling holes for the vacuum lines in a $250 Panasonic inverter unit.

Yeah, here's the latest style here- runs off of black flies and moose droppings (actually the most recent one I bought for home and didn't return)

Current models are all too deep (except the 'low end junk' tiny ones), excepting only expensive commercial units that have inappropriate controls for home use. Probably because of the turntable..

Best regards, Spehro Pefhany

--
"it's the network..."                          "The Journey is the reward" 
speff@interlog.com             Info for manufacturers: http://www.trexon.com 
Embedded software/hardware/analog  Info for designers:  http://www.speff.com

This might explain why: It's not a new phenomenon. Some contest-makers have avoided Quebec over the years because of strict rules governing how those competitions are run in the province. The rules have been in place since 1978 and are designed to protect consumers and ensure prizes are paid out.

Some of those rules include deposits for certain contests depending on where they're being held; registering advertisements before contests begin; and allowing the government to mediate any lawsuits that may stem from contests.

Google for the country names and you'll find that it's a common blacklist for contests:

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558