Neutral is connected to the grounding rod at the transformer. So neutral is almost always very close to ground potential within a couple of volts , all branch wiring and outlets should use ground a green wire.
Essentially No current flows in the ground wire. We use Ground fault interruptors which detect differential current between hot and neutral should be zero if its more than about uA then the GFI opens the circuit assuming that the leakage current is into the frame or chassis and a shock potential exists. I see there are some other answers since I started but they missed the V mark I think my description of the US power distribution is corrrect from an engineering standpoint and the explanation of V is somewhat technical but what you are inquiring about.
Note my use of H1 and H2 are not a standard naming, I just use them so I would have to say "the other hot line". Atta boy, Loring I knew you'd hold your end up! Thank you for your replies and special thanks to you Loring for taking the time to explain it to me. Well, as I said This TS comes in two versions - 1 phase and, 3 phase I have the 1 phase. As you can see on the pic below, the 1 phase voltage is V but, the 3 phase voltage is that if I'll apply the formula of "square root of 3 multiply by V" it will give me To connect 2 or more generators in parallel, I had to turn some small potentiometer that turned the generator faster or slower and, when the phases were synchronized it was indicated by two lights - when they were blinking very slowly or "Off" - it meant that the phases are synchronized I switched the "Bus Tie Breaker" BTB to ON.
Connecting two generators in parallel while the phases are not synchronized i. Thanks again niki. Within each grid there are hundreds of generators running in parallel holding up the load. Every generator must be synchronized with the others or the power would go crazy and probably shear shafts off, too. In the case of a generator, being started, it has to be brought up to speed 60 revolutions per second.
At the turn of the 20th century, the standard means of checking synchronism is the three light bulbs tied between the each phase of the generator to the one phase on the grid. The bulbs will flash on and off at the difference speed, as they approach the bulbs will appear to rotate, the rotation slows as the speeds match and will stop when synched and reverse even if you are going too fast. I'm sure todays synchronizing in done automatically since a manual mismatch on a generator throwing out MW would be catastrophic to something very large generator shafts maybe.
Much more exciting than synchronizing four jet engines. Once synchronized, you power output is controlled by increasing generator torque and increasing the phase a bit so that when you lead the phase you are generating power into the grid and your phase is lagging then you are actually pulling current from the grid bad, unless you are a co-generator with varying power availability and a heavy user sometimes.
At any rate once tied in you are locked to the frequency of the grid which is kept very accurate on a short term and even more accurate on a long term. What I mean by that is they actually count the cycles during the day and if they ran a little slow in the morning they will speed up ever so much to make the days total come out exactly 60 per second over the day. Better even than the quartz clocks and watches because the time source they use to count cycles comes from a clock probably 10, times better than your commercial grade quartz timers.
Niki, I'm sure by "picks" you are probably talking about "Peaks" referring to the phase difference which is usually measured by looking at the peaks on an oscillograph or oscilloscope.
Maybe instructor had a strong accent? Also virtually all power generators are three phase motors run in a generator configuration, shaft is driven and the three windings are the output. Different generators are not used to generate different phases was that a question you were asking?
Some might find this wiki article interesting. The US residential power distribution I described is correctly called Split-phase distribution. The article compares to Europe, it says that Europe homes usually have split phase in the neighborhood developing and V as US homes develop and , but many homes are only serviced by one side of the split phase meaning they won't have over V available.
Loring, I think I know the answer to this anyhow, but did you have to look any of this up? Or did you just know. I'm betting you knew it already. Last edited by cgallery ; , PM. I first learned most all this three-phase-stuff in College EE classes - still remember. It's amazing what a person can learn on this board.
Bob Bad decisions make good stories. Again, I don't have any idea about the 3 phase voltage to the industry in Europe BTW, I was reading some article that the EU decided to convert all the voltage in EU to V some countries were using V and some - UK - V as they explained, it is done so they will be able to supply electricity from one country to another and to make all the electric devices in standard V so they can sell one product in all countries.
On your link, there is a title on "Construction Sites" that says that in UK, in construction sites, they must use V equipment Maybe tomorrow, I'll try to check the Voltage between 2 phases on my electric box So, if you'll not here from me The reason is that it is assumed that the most likely accident is one conductor shorting to the case or through water and contacting personnel who are in contact with ground.
Thus given this scenario you cannot be exposed to more than 55V which is widely believed to be non-lethal given the impedance resistance at 50 or 60 Hz of most people. However the tool still operates with the power of a V tool. That a person might contact both lines and be electrocuted is considered to be much lower probability as in most likelihood he will get a good buzz from touching one line first before the insulation fails on the other line.
Anyway to use these V tools in the manner that UK intended, you need a center-tapped, to step down transformer with the center tap grounded.
Actualy its no problem to produce most any voltage you want. All distribution today is done at a very high voltage from the power plant, often as high as , volts with local substations reducing it to several thousand volts near your homes. The final voltage is created with transformers which decrease the voltage and increase the current so the delivered power is about the same. This reduces resistance losses over long distance since at , the current is low, and allows smaller wires.
USing high voltage directly is impractical due to the tendency to jump gaps and require lots of insulation and be dangerous. Fortunately a man named Westinghouse knew that transformers allowed AC voltages to be adjusted up and down and correctly laid out the basis for the distribution system everyone uses today. It also makes the powerful induction motors of today possible. Post reply. Insert quotes…. Similar Threads A. Comp'Ex' Fail Ex03R. Hi Everyone Thank you for accepting me into this group.
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