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Why lower volts in USA

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  • Why lower volts in USA

    With all the discussion going on about electrical matters. I thought of this question. What are the pros and cons of the different voltages used in countries around the world? I thought a higher voltage system would have an advantage of requireing lower currents to do the same work. I guess higher voltage is a bit more dangerous.

  • #2
    My boss said it had to do with safety.
    I keep hearing cars are going to move to using 48v systems instead of 12, lower amps, smaller batteries, less weight.

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    • #3
      Lower voltages? I worked around 500,000 lines at Sequoah.. On a dry day you can hear in insulators crackle.. your hair stands up..

      Oh.. you mean consumer voltages? We just can't take it.. I got one friend that says he is immune to 120.. He works all the time and his hands are dry like leather.. Some kids were listening. watching.. I suggested he lick his fingers.. I almost had to pry him loose.. I rarely ever get surprised-shocked.. I don't like it.. I can't take it.. Makes me want to break dance.. Spin on my head..

      At least we got away from edison's safe electricity. He wanted DC in all the homes.. generators on every block.. Lots of jobs for us sparkies..

      Nikola Tesla (father of modern 3phase and ac voltage transmission theory in the 1800's) was too smart to be human, read about his life. He liked ultra hi frequency voltages.. They run on the outside of your skin they say.. I did stick my finger into a tesla coil stream.. it burned a black hole in my finger that didn't get well for a month.. Next time I used tin foil on my finger.. It didn't take me long to look at that horseshoe..

      Tesla coils are toys.. RF static if you will.. But very impressive.. purple lightning.. whoo hoo.. sparkly.. I was working on a pulsed Chi-power experiment trying to sychronize my brain waves and pulses of Hi energy power.. It didn't work. Strange things, strange ideals I soon forgot..

      ------------------
      David Cofer, Of:
      Tunnel Hill, North Georgia

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      • #4
        I think I read somewhere that the 110 volt in the USA was a carry over from the tram / trolley bus era where 110 volt DC was the norm, but I may stand corrected on this. Again from memory 220 volt is available in the house to run high draw items such as washer / dryer (workshop) etc.

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        • #5
          <font face="Verdana, Arial" size="2">Originally posted by zl1byz:
          With all the discussion going on about electrical matters. I thought of this question. What are the pros and cons of the different voltages used in countries around the world? I thought a higher voltage system would have an advantage of requireing lower currents to do the same work. I guess higher voltage is a bit more dangerous. </font>
          Yes.

          And the combination of higher voltage and lower frequency (240V 50Hz) is even more hazardous, since it will produce more current, which will also flow deeper inside you.

          High frequencies flow more towards the surface. DC goes through the entire conductor cross-section. And at the diameter of people, 60Hz does have some effect. Depends on the resistance you assume for the inside of people.

          Not a big difference in frequency, but just that much less safe, added to the increased voltage.

          DC is nasty. Got into the 450V Dc in a piece of equipment once. Just one hand.
          Blew little pits in the skin. Nice that it didn't go across me from arm-to arm. That would have been "not-nice".......

          1601

          Keep eye on ball.
          Hashim Khan

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          • #6
            The pros and cons- the higher the voltage, the less current needs to be drawn for the same power level. That means easier starting for induction motors, higher available power at a socket for an equivalent breaker rating, and the possibility of lighter conductors for an equivalent power rating. Longer lines would be possible for the same loss, and less loss for an equivalent wire size and length. Higher voltage means greater possibility of electrocution, since it's a little easier to jerk free from a 110 vac shock than a 240 v one. Higher voltage taxes insulation more, and might require better switches, since arc suppression would be a bigger issue. One thing that doesn't have as much to do with voltage, is the level of regulation. In the continental usa, and in canada, we generally have well regulated voltages, but in many european countries, there can be a large change in supplied voltage. I've seen it go from 175 to 280 vac where I was in africa. That was some time ago, but I think the problem remains more of an issue 'over there' than it is here, regardless of voltage. For us, using 220 for a machine would improve our already better regulation, since as currents drop, so do voltage drops, given an equivalent gauge of wire.

            48 volt systems in vehicles? I can see it now, every electrical thing you could ever buy as a replacement item for the car would become more expensive. It wouldn't have to be, but you can be sure you're going to pay more for it. There is no problem now with voltage regulation in a vehicle, the alternator takes care of it nicely. Who ever had a problem because the system is only 12 volts? The starter would certainly draw less amps, but a 48 volt system would use smaller batteries, and more of them to get the 48 volts, so the current draw vs voltage drop problem would remain the same. The move to 48 volts won't solve anything, or make anything better, in fact it will make it more dangerous for anyone working on the vehicle. But it will cost you more for every part, from that point onwards, forever. That's just a blatant move to get more money out of your pockets.MHO
            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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            • #7
              Hell Dave you can shove 500kv, thats way too scary. I worked in a switchyard with 220kv down to 50v comm. I didn`t much care for that high voltage stuff, that EMF does wierd stuff. The turbine / generators on the turbine floor only put out 30mw but I never felt comfortable at the generator end!
              I visited the Huntly power stn once, when I got onto the generator floor my body felt soooo strange that I had to leave. There have been some strange consequences for some people who work in high voltage enviroments, cancers ,suicide . Asbestos and hp steam leaks never appealed to me either.
              Ken

              [This message has been edited by speedy (edited 09-11-2004).]
              Ken.

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              • #8
                So we can run our 5hp. compressors in the living room, if we want to.

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                • #9
                  Electrical power is really a strange animal, some standards are because of the fight between AC and DC. For a while I worked around a Cray Super Computer and it required a MotoGen to get the right voltage and frequency for it's operation.

                  In the U.S. Military many field items run on 24 volts. In some places 30 volts AC was still being used in the 1970s.

                  The standards are what somebody makes them, sometimes they are what the equipment or the consumer really needs.

                  Jerry

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                  • #10
                    The different voltages are no big deal, all that is required is a transformer to change one to the other. However, in Europe they use 50 Hz versus 60 Hz here. don't know why.

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                    • #11
                      Okay,pop quiz,why does soo much military stuff require 400hz?
                      I just need one more tool,just one!

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                      • #12
                        <font face="Verdana, Arial" size="2">Originally posted by jfsmith:
                        Electrical power is really a strange animal, some standards are because of the fight between AC and DC. For a while I worked around a Cray Super Computer and it required a MotoGen to get the right voltage and frequency for it's operation.

                        In the U.S. Military many field items run on 24 volts. In some places 30 volts AC was still being used in the 1970s.

                        The standards are what somebody makes them, sometimes they are what the equipment or the consumer really needs.

                        Jerry
                        </font>
                        Always liked crays... I'm curious, so what was the voltage frequency it needed? And what was your job at that time? Did you get to work on the cray at all? (if so, lucky bastard!)

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                        • #13
                          In response to wierd's quizz, 400Hz motors are smaller and lighter weight for a given output, important criteria for things that are supposed to fly. From memory the 707 had a complex varidrive A/c system to maintain frequency at varying drive input speeds. Today its done electronically and to get DC current Transformer Rectifer Units (TRU's) are used in larger aircraft, the old DC gen is being replaced.

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                          • #14
                            Speaking of High Voltage, this is worth a look at....
                            http://www.wiseguysynth.com/larry/day.htm

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                            • #15
                              I once disasembled one of those disposable cameras with flash. I knew that big ol capacitor was charged for the flash, but I still managed to touch the leads, made my whole body shake for a few moments. Sad part was that I managed to do it a few more times. One time I dropped the assembly right onto my lap and it got me.
                              Really, 450v from that capacitor aint as bad as you would think, you'll still dance though.

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