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Anonymous at Sat, 30 Mar 2024 22:22:38 UTC No. 16105482
If the 3 phases of AC are all the same voltage curve shifted by 2 pi/3 with respect to each other does that mean that, theoretically, touching all 3 phases at once provides no voltage difference at all?
I realise this is not possible in practice but I'm just trying to validate my understanding.
Anonymous at Sat, 30 Mar 2024 23:02:18 UTC No. 16105539
>>16105482
>theoretically, touching all 3 phases at once provides no voltage difference at all?
think of voltage like a hill. the same location can't have 3 different heights.
another way to look at it is if you connected all three together with a good conductor, that would short the three lines and once again potential difference would be close to zero
Anonymous at Sat, 30 Mar 2024 23:10:27 UTC No. 16105553
>>16105482
If you only touch one of them (and have no dispersion to ground) you should only get a capacitive effect, but not much current through you--DON'T EVER TRY IT, you still risk having some dispersion and getting shocked or die.
If you touch two or even all three, you will get all the current through you, between the points where you are touching the different phases.
If you touch two or more phases in exactly the same spot, like all 3 on the exact tip of your index finger, then you will make a short circuit between the cables and no current will flow through you--DON'T EVER TRY IT, you will still suffer from the heat generated by the short circuit and possibly have dispersion and get shocked and die.
Anonymous at Sat, 30 Mar 2024 23:32:01 UTC No. 16105578
>>16105482
no, touching 3 phases means you always have a big non-zero voltage between at least 2 of them at any given moment. touching only 2 phases you could time it when the voltage between them is zero or at least small. for like 1ms at 50Hz or 60Hz so good luck.
also only works if the star point isn't grounded.
Anonymous at Sun, 31 Mar 2024 03:13:02 UTC No. 16105800
>>16105482
You could create a short using a conductor that would bring the voltage at the center of the star point to near zero, but you'd also be creating a very very high runaway current and well it would cause arcing and a total meltdown of the conductor because too little load. You could be greatly injured or killed if you're anywhere near this.
Anonymous at Sun, 31 Mar 2024 19:18:14 UTC No. 16106620
https://www.wolframalpha.com/input?
You are right. Its identically zero. But reminder that any two phase have 400volt difference in EU
Anonymous at Sun, 31 Mar 2024 19:54:47 UTC No. 16106660
>>16105482
>theoretically, touching all 3 phases at once provides no voltage difference at all?
Maybe not, methink there are three independent power lines. Each is called a phase. Return is always over ground (earth). That's were the second point of the generator/transformator coil is connected to.
There is a voltage difference between the lines, caused by the phase shifts . Due to common ground too. The phase shift is constructive by generator design. If cosPhi = 0 the system is in sum! 0 Volt but each phase has the normal electrical props of an single phase system. Shorting between phases will generate huge balancing currents. Then it becomes complicated, they flow through the different transformator/generator coils and ground which is non straitforward.
Don't shoot me if i am wrong or bad formulating, i am not an power electrician.