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  1. #41
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    Quote Originally Posted by hanermo View Post
    The EU / global 50 Hz-type 3-phase grid with 220V household power needs much smaller wires in houses and permits easy, cheap, and fairly common 3-phase power wherever users want it.
    3-phase mostly has little/no structural costs to deliver to any consumer who wants it.

    Depending, eu, 3-phase may have zero installation costs (modern) to very high costs (antique old city centers and protected buildings and no infra).
    .....


    The EU 2-phase AC is much simpler than the US system.
    Less wires (US has 3+gnd, no), not keyed, much less copper and cost, half the wire thickness.

    And dual igbts mean the system is very safe.
    I have shorted the main power by hand, tripping the igbts.
    Nothing happens.
    Not dangerous, no burns, hurts quite a bit.

    .....
    A couple details that are often not realized about US power.

    1) it is delivered to the house as 240VAC

    2) The delivery wiring is 3 wires.... 2 "hot" and one grounded (neutral). 240V between hot wires. 120V line to neutral

    3) The UTILIZATION voltage may be either 240V OR 120 V. Ranges, A/C, hot tubs, hot water heaters, etc use 240V.... any high power load does.. Regular outlets use 120V for lower power, but it is perfectly legal to have a 240 V outlet anywhere. The 240V uses a different plug..

    For some installations, as in apartment buildings, 208V 3 phase is used. Then there is 208V between the hots, and 120V to neutral.

    For a 240V (208V) circuit, there are 2 wires and earth as you have. So, a floor cleaner or the like would use 3 wires.

    Some special circuits do use 4 wires, mostly because cheap ranges and dryers use 240V AND 120V, so they need a neutral.

    So, really, there is not a great deal of difference, we just have one additional voltage available, which happens to be the common voltage for lights and other low power items.

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    Quote Originally Posted by Froneck View Post
    I read what Tesla claimed. Something must have been correct since all power generation in all countries is 50 or 60Hz. I haven't heard of anyone planning or even arguing it should be increased. I know aircraft us 400 Hz, read sometime ago why but can't remember!
    Historical reasons are the biggest single motivation for 50 or 60hz.
    Germany was seriously considering switching to 400hz after the WW2 as lots of the infrastructure needed to be rebuilt anyways.

    50...60hz is adequate compromise between transformer size (higher frequency would let you use smaller transformers) and long-distance reactive losses (underground high voltage lines at 400hz would be LOT more difficult. Or long (>1000km) air lines)

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    Quote Originally Posted by 9100 View Post
    I looked at Schumann resonance. Our brainwaves are changing the resonant frequency of the earth's electromagnetic field???? Apparently some people take it seriously.
    Bill
    Now how and where on earth did you find that? The text I found was much more sensible.
    fusker

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    wikipedia.com has a long and seemingly plausible article on Schumann resonance.
    The ionosphere seems to act like an electromagnetic wave guide. Oscillations are triggered by lightning and are in the VLF (very low frequency) range, around 10 - 100 CPS (or Hz as we say here). Apparently many scientists are studying the phenomenon which was predicted a hundred years ago but is quite difficult to register.

    Of course, once this becomes common knowledge many crackpot theories of brain waves etcetera will be published.
    fusker

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    Quote Originally Posted by fusker View Post
    Now how and where on earth did you find that? The text I found was much more sensible.
    fusker
    What does the spike in the Schumann resonance mean? – Dr. Joe Dispenza’s Blog

    Google "Schumann resonance spike" and you will turn up far more nonsense than I have the patience to read.

    Bill

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    Sometimes the "nonsense" is based on misinterpretation of, or false theories built on, a real phenomenon. So somewhere buried in the noise (just read the comments at the link) there may be something interesting and worth study. There is some reason to be interested in the effect of external fields on brainwave activity, after all there is such a thing as electromagnetic interference in electronics, which can have unforeseen effects.

    No really good reason brain waves should be different. The real question is whether there is sufficient field to make a difference, whether it can be picked up with an "antenna" the size of a person, and the like. it's interesting, but the conspiracy theorists have to assume the existence of someone who understands and is manipulating the system, which is a bit questionable.

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    9100, there is an enormous gap between "Dr." Dispenza's blog and the article in wikipedia. I managed to read twenty lines of the good doctor's ravings, then my patience ran out too, so I dispenzed with him (sorry, couldnt help it).

    As someone said, there's more nonsense between Heaven and Earth than anywhere else.

    JST, if our brain waves could be artificially interfered with, someone would surely have done it already.

    fusker

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    The problem here is that many effects that proved to be true were originally met with skepticism. Before James Clerk Maxwell's calculations, suggesting that there was an invisible wave that went through the air and not only could provide communication between any two points in the world, could be bounced off other planets, and also cook food would get you laughed off the stage.

    Same for tiny invisible creatures that made you ill and countless other things like X-ray, MRI, and on and on.

    I don't believe these theories about ELF waves, but you cannot completely disregard them.

    Bill

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    Okay, so after all the amusement of both physics fact and theory, and phenomena yet undetermined, here is the REAL reason why...

    Tesla worked for Westinghouse.

    Westinghouse was a RAILROAD baron. Think AIR BRAKES. He was in the railroad business FIRST, and moved to electricity because he realized TIMES were CHANGING.

    He pushed into railroad signaling... you know... stop lights... switches... block protection...

    What's the #1 critical aspect of railroad operation?

    The watch, in your pocket. Every railroad officer had a watch. Every railroad station had a clock. Every clock was synchronized EVERY DAY via TELEGRAPH SIGNAL.

    Prior to electric clocks, every clock, every watch... was hand-wound. Railroad policy had a formality that was adhered to with extreme rigidity- synchronizing the watches.

    An electric clock is a mechanical gadget that makes a specific number of rotary motions in a fixed time frame.

    Nikolai Tesla's assignment by George Westinghouse, was to make an electric clock who's second-hand would reliably rotate exactly 1440 times in one day... 60 times an hour... once per minute.

    And Nikolai made it happen using a 60hz shaded-pole AC motor. Connected to a 60-cycle nationwide grid, it would always be within a second or two.

    All of Westinghouse's railroad switchgear timers are built on this same principle.

    Consider THAT, the next time you hear someone mention that 'Mussolini made the trains run on time'.

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    So why 50, 40 and 25 Hz?

    Tom

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    Iron losses were high, lower frequency but larger transformers cost more but were more efficienct.

    16-2/3rds was generated by rotary phase converters to drive previously dc series and parallel wound train traction motors. 60 was too fast for two reasons. One being leakage inductance in the field coils and the other being the iron laminations too thick

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    This article covers it all.

    Utility frequency - Wikipedia

    Tom

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    Why 60 cycles for the clock? Any even number of cycles is just a matter of the number of gear teeth. When I worked with 400 cycle equipment a lot, one of the main annoyances was that 60 does not go into 400 evenly. We had a couple of motorgenerator sets with adjustable pullys that were reasonably close, but nothing was dead on 400 except tube amplifiers fed by accurate oscillators.

    Bill

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    Because clocks were made with gears, hours, minutes, and seconds are all based at 60, not 25, not 100.... and a circle is divided in fractions divisible evently by two... 360 degrees, 180 degrees, 90 degrees... Divide a circle by 50, and how many degrees do you get? 7.2. hard to make a gear tooth that way, and have 'easy math'.

    Your observation of acquiring 400hz from MG sets with accuracy, is exactly th esame situation they faced with electric clocks and frequency standards.

    If the power line frequency was not also providing a time standard, it would clearly have been some other frequency... but remember the electric clock you had in grade-school? Plug it into the wall... it had NOTHING in it that would serve as a time reference... just the motor.

    Yes, <I have a Hammond... an M2... and a Rhodes 77, but not a Clavinet or Mini-Moog...)

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    Interesting reading. To get back to the US standard 120VAC 'house current', it traces directly back to Edison's invention of the incandescent lamp. Edison's big problem was finding a material that would have decent life for the filament. When he had his carbon filament material, he then did some experimentation as to what voltage gave the longest life, and settled on 110 volts. Of course the original Edison system was DC, but when Westinghouse was pushing their AC generating and transmission system, there was already a large installed user base of Edison lamps, which would work just fine on AC, so long as it was the correct voltage, which led Westinghouse to adopt 220VAC for their 'service' voltage, which was then center tapped to provide 110V for the lighting circuits. Our utilization voltage has since been raised to 240/120VAC, but that was long after carbon filament lamps were obsolete.

    Chicago was another pocket of 25'cycle' industrial power; the entire transit system originally ran on this system. One of the reasons that the Chicago Transit Authority has no neat historic rotary converter substations left is in the sixties Commonwealth Edison, the local electric utility wanted to stop supplying 25 Hz power, so the transit authority was forced to do a huge capital improvement program to replace all the substations that supply 600 VDC for the subway system, and all were replaced with modern rectifier equipment. Converting the subway was a must, but the decision was made to not spend the money to convert the former streetcar substations that powered the electric bus system, and by 1972 or so all the electric buses were gone.

    Dennis

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    Minor quibble- Edison did not invent the incandescent lamp. There were dozens on the market. Swan in England was in the business and Sawyer-Mann probably should have been the US manufacturer if Sawyer had not been so difficult to deal with. "Evolution of the Incandescent Lamp" by Franklin Pope, published in 1889, only mentions Edison in passing and does not consider him an important player. Hiram Maxim was making lamps until someone suggested that if he really wanted to make a lot of money, to come up with a better way for Europeans to kill each other in the incessant wars there. Maxim took the advice and made the Maxim machine gun. If you want to read some history of that era, look up Lewis Howard Lattimer.

    Edison accomplished two things. First was what was called "subdivision of the electric light", that is, making small ones, and he did the same thing Bic did for ball point pens. While others were making large bulbs that could be repaired, Edison made cheap, small throwaways. Actually, you didn't throw them away; you returned them for the factory to salvage the platinum in the leads, but the bulbs were not salvaged. Edison's patents for the lamp are detail improvements, not overall coverage because those were well known already. Edison's lamps used a higher voltage than most others, which were low voltage, high current and had to be used in series or accept large line losses.

    Bill

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    Quote Originally Posted by 9100 View Post
    Minor quibble- .... ...Edison's lamps used a higher voltage than most others, which were low voltage, high current and had to be used in series or accept large line losses.
    Bill
    I'll add note that railroad cars were illuminated with electric lights before most homes were. My dairy barn was illuminated with electric lights a decade before my farm's four-square was built. It was formerly 72vdc, by virtue of glass batteries recharged by a hit-and-miss pumpjack with auxiliary dynamo.

    Our common 120v power is not random... but there's a reason why you see 110v and 115v. There's also a reason you see 90VDC motors. Passenger railcars and locomotives still use 72v as a DC battery... a carry-over from the big glass-cased nickel-iron and nickel-cadmium batteries who's successors STILL sit in big racks on each side of locomotive noses, and in the box below equipment cabinets of railway signalling huts. Those relays were all wound to operate as low as 70v, and as high as 90v. The signal solenoids and electric switching motors... 70-90vdc. There were even small air-compressors running on 70vdc motors, to provide high actuation force for railway switches, and electrical switchgear.

    These batteries had to be charged by SOMETHING. On DC, they used whatever dynamo they had on hand, and adjusted the dynamo's speed to yield appropriate charging voltage, which is why you'll see antique engine-driven dynamos in the 110vdc range. If you do some math, you'll find that the RMS value of 115vac, you get... 80... which is within reasonable range of being used to charge the big cells, and the railroads did... they used a rectifier tube and a variable resistor.

    Now, my previous home was along the Mississippi River, and the back of the property had a right-of-way for the Clinton, Davenport & Muscatine interurban railway. The railway's right-of-way was negotiated in 1899, the railway's first segment went active in late 1904. It was powered by catenary 600Vdc, which was energized by steam dynamos, but there were some long spans, so the cars ran a 'little slow' in the long-reach spots... but notable that the 'private right-of-way' was negotiated with landowners along the river, my former property being one of them, and in the abstract, the right-of-way agreement clearly stated the terms of the right-of-way easement included electrification of the house with 1 electric lamp in each room, one electric outlet in the kitchen, and one electric outlet in the living room. The wiring from this as well as one of the 72v lamps, was still in place, (but not connected) when I renovated the kitchen in the fall of 1993... but my neighbor's photos revealed how they got DC power to the house- at the signal box down the block, was a motor-generator, that took high voltage DC from the catenary, and output low-voltage DC to that signal box, and the houses of the block.

    My neighbor Dean (now passed) was kind enough to take time to talk about it, and the one thing he mentioned that was particularly amusing, is that he rode the train into town every morning for school, he knew when the train was coming, because the lights would dim in the house each time the train started from a stop... each time, the lights would dim more... he always knew when it was going to arrive... and since it was a railroad, it ran on a timetable, so he would always check the family clock, and correct it, against the train's arrival.

    Here's a good historical read:
    Westinghouse batteries and industrial lead-acid accumulators

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    And by the way, since 9100 noted... Sir Hiram Maxim invented his automatic gun, his brother Hudson was inventor of firearm powder and explosives, his son Hiram Percy Maxim invented the 'silencer'... initially for the purpose of reducing noise from the recent invention 'internal combustion engine', it was also very effective at reducing the report of sealed-breech firearms...

    but don't believe what the movies show... a silencer on a revolver, or a slide-automatic, is a silver-screen joke.

    Hiram Percy Maxim is also considered a icon of radio, particularly Amateur Radio... referred to as 'The Old Man', one of the founders of the ARRL, and inventor of the Wooff-Hong, and the Rettysnitch.

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    Quote Originally Posted by DaveKamp View Post
    but don't believe what the movies show... a silencer on a revolver, or a slide-automatic, is a silver-screen joke.
    Not completely. When The Guns of Navarone was in the theaters with commandos running around piffing at people with their silenced Berettas, friends wondered if silencers really worked that well. I made one on the Maxim pattern for a .32 automatic. With standard velocity ammunition it was quite effective. You could hear the clank of the slide, but no one would identify it as a shot. I fired it in a back yard on Bemiston Ave. in Clayton and then asked a man working in his back yard two doors away if he had heard it. He said he heard a couple of pops but didn't think anything of them. If I fired it at a piece of wood, I could clearly hear the bullet hit it.

    I don't normally post things like this but I hope the statute of limitations has run out since 1959.

    The standard CIA assassination weapon was and may still be a High Standard .22 with a silencer.

    Someone made an automatic with rubber pads on the mechanism.

    There was one revolver that was super quiet. The designer fitted rings of some sort of composition in the front of the cylinder in counterbores. The gases would push the ring tight against the end of the barrel, sealing the side spit. It had the additional advantage of not leaving traceable brass lying around.

    Bill

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    Quote Originally Posted by 9100 View Post
    Not completely. When The Guns of Navarone was in the theaters with commandos running around piffing at people with their silenced Berettas, friends wondered if silencers really worked that well. I made one on the Maxim pattern for a .32 automatic. With standard velocity ammunition it was quite effective. You could hear the clank of the slide, but no one would identify it as a shot. I fired it in a back yard on Bemiston Ave. in Clayton and then asked a man working in his back yard two doors away if he had heard it. He said he heard a couple of pops but didn't think anything of them. If I fired it at a piece of wood, I could clearly hear the bullet hit it.

    I don't normally post things like this but I hope the statute of limitations has run out since 1959.

    The standard CIA assassination weapon was and may still be a High Standard .22 with a silencer.

    Someone made an automatic with rubber pads on the mechanism.

    There was one revolver that was super quiet. The designer fitted rings of some sort of composition in the front of the cylinder in counterbores. The gases would push the ring tight against the end of the barrel, sealing the side spit. It had the additional advantage of not leaving traceable brass lying around.

    Bill
    I had an experience many years ago with a silencer that had been fitted to a .22 varmint rifle. The user said it really didn't do much. After doing some research, I recommended a sub-sonic .22 round. That did the trick. The crack of the first the round was the breaking the sound barrier.


    Tom


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