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Author Topic: Astron Power Supply efficiency  (Read 16228 times)
WX7G
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Posts: 6136




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« Reply #30 on: February 23, 2011, 12:08:57 PM »

I do see where you're coming from on CR. I believe that running a higher compression ratio (CR) is just a means to an end. The next intermediate goal on the way to higher efficiency is a greater temperature differential (there's that heat engine thing again) and a higher CR is just a means to this end.  

IC engines do run some pretty high compression ratios these days thanks to electronics. What is the CR of a WWII era 115 octane engine?


« Last Edit: February 23, 2011, 12:11:25 PM by WX7G » Logged
W8JX
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« Reply #31 on: February 24, 2011, 08:16:04 AM »

I do see where you're coming from on CR. I believe that running a higher compression ratio (CR) is just a means to an end. The next intermediate goal on the way to higher efficiency is a greater temperature differential (there's that heat engine thing again) and a higher CR is just a means to this end.  

IC engines do run some pretty high compression ratios these days thanks to electronics. What is the CR of a WWII era 115 octane engine?


The "effective" CR was about 14 to 1 in that they typically ran about 65 inches of mercury of absolute manifold pressure at rated output. (about 16PSI of boost relative to sea level or about 31 PSI true pressure) They experimented with a P47 running as much as 90 inches of mercury (abt 30 PSI of boost) to increase level flight speed to over 500 mph to try to deal with potential German ME-262 threat. Threat never real materialized in a large scale and project was abandoned but they did break 500 in testing. If you can believe it they had cooling problems with engine getting warm enough to run properly. (they had some other problems too)

On the flip side pre 1973 cars had factory CR's as high as 12 to one in some models when 100 plus octane leaded fuel was widely available. Main reason CR was chopped 8 to 1 in 73 was to reduce NOx emissions as higher CR's generate it in higher amounts and there was no technology to control it otherwise.  When this happened MPG really went down toilet for many years. Today they have restored some compression and use advanced fuel management and spark knock control to tolerate low octane fuel and reduce/eliminate consumer complaints of fuel knock as they strive to buy and burn cheapest possible fuel. It is a double edged sword though in that while it masks fuel knock really well it reduces efficiency a lot at times. Particularly in warmer weather and when towing or loaded heavy.  If many would run a higher octane fuel they would find they would get better power and economy. Problem is engines are quick learners when low octane fuel is used (they have a knock sensor that detect vibration of knock potential before you even hear it and quickly retard spark curve) and slow to restore timing curve for higher octane fuel and if you switch you will not see a change for a few tanks of fuel unless you pull ECM fuse and force it to relearn spark curve. The ONLY reason modern engines have spark management is for knock prevention and to limit consumer complaints as it serves no emission purpose. In "old days" you knew when you were not feeding your car proper octane as it knocked but today it is hidden/masked. If they were to put a "octane" light on dash that lit every time spark was retarded to control knock you would realize how much 87 octane hurts you at times. But then that will never happen because many would complain of it being on nearly all the time with 87 octane fuel and consider it a car defect and not operator error from feeding it wrong fuel.
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N8CMQ
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Posts: 375




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« Reply #32 on: February 24, 2011, 09:03:39 PM »

Hog wash, this is the same crap that has been forced on the public since the seventies...
They just claim it is "Going Green" today. There is no green if it uses any fossil fuel.
But how many want to go back to caves and animal skins? I sure don't.
Oh ya, let me jump into my flying car and buzz over to the automart for lunch...
Don't get that last line, you're too young...
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W8JX
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« Reply #33 on: February 24, 2011, 09:17:40 PM »

Hog wash, this is the same crap that has been forced on the public since the seventies...
They just claim it is "Going Green" today. There is no green if it uses any fossil fuel.
But how many want to go back to caves and animal skins? I sure don't.
Oh ya, let me jump into my flying car and buzz over to the automart for lunch...
Don't get that last line, you're too young...

There will always be sheep that will follow those how want to believe that all is well and fish bowl we live in will never fill up and oil will never run out. They are the ones that ignore science too. Wishing is not gonna change things. To put this into perspective, here in US we use the equivalent of about 125,000 semi tanker trucks of oil a day. Bumper to bumper it would make a line nearly 1800 miles long, every day, day after day and it cannot go on for ever. And, of all the know proven reserves in world the US owns or controls less than 3% of them. Remember the big stink about ANWR oil reserve in AK? They never bother to tell you in fine print that at its peak it would never make more than 1% of US daily needs and if it could be fully recovered all at once there is less than a years supply of oil in it based on US consumption. But again those promoting it never bothered to tell you that.
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N0SYA
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Posts: 369




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« Reply #34 on: February 28, 2011, 09:07:41 AM »

if only the warmers/greenies would do the right thing, the one thing that will keep them from being hypocrites and live in caves eating roots and grubs, traveling only by foot, there would be just that much more energy for the rest of us

Cheesy
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If you have a clumsy child, you make them wear a helmet. If you have death prone children, you keep a few clones of them in your lab.
W8JX
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Posts: 6093




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« Reply #35 on: March 01, 2011, 04:56:44 AM »

Ignorance of problem will not make it go away and will only make it more costly to fix long term.  Their are some in politics that believe never fix today when it can be fixed later for 5 to 10 times the cost because it "looks" better today.   
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NO9E
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Posts: 417




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« Reply #36 on: March 02, 2011, 01:28:13 PM »

Coming back to power supplies.

MFJ switchers are considered quite clean but generate birdies on 160m. Those birdies drift a bit and are are dependent on load. Probably same with other switchers as filtering lower frequencies is more difficult. So when one is running and those real DX start coming in, the birdy moves in and jams!  Not a problem if one has a beverage 500 feet away but a problem with K9AY next to the house.

The moral end of story: linear PS may be still preferable for top banders.

Ignacy, NO9E
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WB6DGN
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Posts: 619




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« Reply #37 on: March 09, 2011, 11:16:58 PM »

And THEN, there's the issue of reliability!  There's got to be a reason why, every time I have to leave for an hour or more, I go around turning off and unplugging every switcher I'm unfortunate enough to own. With few exceptions, I consider them a potential fire hazard and the ones that I do trust are VERY pricey.  I've seen them fail.  They not only let the smoke out, but, often, a few flames as well.  As for me, I'll stick with my linear supplies as long as the law will let me.
By the way, thanks for the article even though the method and equipment used to measure power consumption was conspicuously absent.  I would have expected a bit larger difference.  Now you need to compare them against the ferroresonant supplies used in an earlier generation of two-way gear (Micor, MastrII, for example).  Those will REALLY make your switchers look good (but NOT any more reliable!)
Tom DGN
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W8JX
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« Reply #38 on: March 10, 2011, 06:50:05 AM »

I have had my switch for 3 years now and I would by more. Every time you turn on your PC, laptop with power adapter, new HD TV and so on you are using a switching supply. They are far more reliable than you give them credit for. I never unplug anything but I do have most devices plugged into surge suppressors and have for many years. Any addition pwr supplies I buy will be switches.
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K7KBN
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Posts: 2814




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« Reply #39 on: March 10, 2011, 04:54:47 PM »

Hog wash, this is the same crap that has been forced on the public since the seventies...
They just claim it is "Going Green" today. There is no green if it uses any fossil fuel.
But how many want to go back to caves and animal skins? I sure don't.
Oh ya, let me jump into my flying car and buzz over to the automart for lunch...
Don't get that last line, you're too young...

I think you meant automat.  Prof. Peter Schickele reminded us of them in the "Concerto for Horn and Hardart".  (Google "Horn & Hardart", with or without the quotes.)

73
Pat K7KBN
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73
Pat K7KBN
CWO4 USNR Ret.
W3LK
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Posts: 5639




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« Reply #40 on: March 10, 2011, 07:02:45 PM »


I think you meant automat.  Prof. Peter Schickele reminded us of them in the "Concerto for Horn and Hardart".  (Google "Horn & Hardart", with or without the quotes.)

73
Pat K7KBN

I have that album, as well as all the others. Did you know that Schickele was actually the conductor of the Baltimore Symphony Orchestra at the time the Peter Schickele albums were recorded?
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WB6DGN
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Posts: 619




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« Reply #41 on: March 10, 2011, 10:11:27 PM »

Quote
Every time you turn on your PC, laptop with power adapter, new HD TV and so on you are using a switching supply. They are far more reliable than you give them credit for. I never unplug anything but I do have most devices plugged into surge suppressors

Yes.  In fact it was a popular brand PC supply that was one of the ones that "let the flames out".  Having been an electronics (LMR) tech. for just over 50 years I am familiar with which of my devices have switching power supplies, hence my comment about the ones I unfortunately own.  As for "surge suppressors", they don't prevent failures from anything except surges (if you're lucky).  Even then, it takes very good quality ones, constantly maintained (read frequently replace the battered MOVs) along with a properly designed and installed single point ground system, for them to be effective.
By the way, I was recently reading an article about a study that examined the "leakage" current, and, thus, unintended power consumption, of the increasing numbers of devices that are never actually turned off (most switching power supplies fall into this category).  The on-off switch cuts power OUTPUT from the device, NOT power INPUT to it.  While the current used per device while in the "OFF" state is quite small (in the microamp range), the massive and ever increasing numbers of these devices is having a significant impact on the demands made to power generation facilities.  Could this, perhaps, indicate that a large percentage of the "power savings" of these types of devices is, in reality, illusory?

You like your switchers; in their present state of development, I loathe them.   I'm sure that nothing I say will change your mind and I'm equally certain that AT THIS TIME nothing will change mine either so these exchanges could probably go on ad infinitum (much to the dismay of other readers, I'm sure).  That said, I'll wish you luck with yours and call it a day on this topic.
Tom DGN
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K7KBN
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Posts: 2814




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« Reply #42 on: March 10, 2011, 10:28:30 PM »


I think you meant automat.  Prof. Peter Schickele reminded us of them in the "Concerto for Horn and Hardart".  (Google "Horn & Hardart", with or without the quotes.)

73
Pat K7KBN

I have that album, as well as all the others. Did you know that Schickele was actually the conductor of the Baltimore Symphony Orchestra at the time the Peter Schickele albums were recorded?

I wasn't specifically aware of that.  But I did get a chance to meet him at a birthday roast for one of the other old-timers in the Bremerton Symphony.  This guy had been pretty close friends with the Prof. in school, and without any fanfare, Schickele shows up for the party!  This was only a couple years ago.  He looks a bunch different up close and dressed semi-regularly than he does in his PDQ mode as seen from a hundred feet or so away.
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73
Pat K7KBN
CWO4 USNR Ret.
W8JX
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Posts: 6093




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« Reply #43 on: March 11, 2011, 08:51:45 AM »

You like your switchers; in their present state of development, I loathe them.   I'm sure that nothing I say will change your mind and I'm equally certain that AT THIS TIME nothing will change mine either so these exchanges could probably go on ad infinitum (much to the dismay of other readers, I'm sure).  That said, I'll wish you luck with yours and call it a day on this topic.
Tom DGN

To me a Switch vs Linear supply is like having a 15 mpg car vs a 20 mpg car. Both get you there but one costs less to run. You could say that maybe a switch saves you 20,40, 60 bucks (or much more a year if you use them a lot) it is still money to spend on something else instead. Kinda like toilet paper in that you flush it away and no sense in spending excessively here either. BTW I have seen some spectacular failures of linear supplies but the few switches I had fail (laptop pwr adaptors after 1000's of hours of usage) simply died with no "show". 
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KJ6HYC
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Posts: 103




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« Reply #44 on: March 12, 2011, 10:37:03 AM »

Now that we have saved the planet, worked out the gas mileage, how about back to the original thread? Linear vs. switchers efficency? The linears are the old tryed and true method, and the switchers are the current and more complex technology. I have found that with either one, if it is quality, it lasts. The switchers are much more efficent, so depending on your on-line hours, electric cost, and cost of additional air conditioner heat load, you would have to calculate the pay back period for a switcher upgrade. I have recently picked up a good quality 13.5V 25.8A 350W chinese switcher on E-baY for $38.00 delivered to the USA. Runs my FT 896 at 100W no sweat. Wasn't difficult to justify, as my electric is at $0.20 KWH w/all taxes/sur-charges etc. 
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