Three Phase Configuration

1 phase = 2 wires.

2 phase = 4 wires

3 phase = 3 wires

4 phase = 8 wires

5 phase = 10 wires

Need I go on?

Not quite true (or complete if you wish ) 2 phase .. not efficent 3 wires 4 posible , 3 phase .. good eficency 3 or 4 wire , 4 phase could be a bit better than 3 but uses 4 or 5 wire , 5 never seen it , 6 phase most often seen as 6 wire could be 7 good for very smooth high torque app. 9/12 phase seen but not any real advantage I have heard of.

Hi

In response to previous posting....all is relevant and correct, however three phase is the most efficient in all aspects.

More than 3 wires becomes expensive when you consider the manufacturing side of things. Motors would require more sets of windings, poles etc.

Calculations from engineering point of view through to the tradesmans point of view also adds more chances for human error in final product.

There are many more answers but at the end of the day when countries unite to create standards they opt for the easier and more simplified solution with the main goal of smooth, balanced energy still in scope

ok

thanks you so much...................

but i 'll be very very happy if you tell me about the power of each type, if you dont know thanks too much..................

thanks

one phase motor will not start in a preferred direction, you need a capacitor to create a leading phase to make it go that way. A single phase motor with no start capacitor can be hand spun to start in either direction.

2 phases = same problem. 3 phases and you get hard wired directionality with lowest wire count.

According to local folklore, the phase rotation in the Liverpool area goes "the other way round" compared to the rest of the country. At some point in the local distribution network, two of the phases became inadvertently crossed over at some point in the past. It is practically impossible to correct the mistake, as to do so would immediately cause every three-phase motor downstream of the mistake to run backwards, with potentially catastrophic results...

The power of each? What do you mean?

Power is power, phases make no difference in the quantity, just the quality. Polyphase power is better than 1 phase because its creation of torque in a motor is more continuous. The more phases you have, the more smooth the power conversion is, but that only counts for mechanical continuity. So in a polyphase system, 3 is the most efficient use when all things are considered, i.e. wiring cost, copper cost, equipment cost etc. 6 phase would mean a more smooth delivery of rotational energy in a motor or less ripple in an AC/DC rectifier, but the added complexity would not be worth the additional costs all around. The old law of diminishing returns. 3 phase is a simple as you can get and still be optimal about power conversion.

In stepper and servo motors, where power conversion can show up as micro-pulsations, they do indeed use 4 and 5 phase for motors. That's because in those cases, the returned value of better precision at the motor shaft may be worth the additional cost for the motor and driver.

Relative to AC/DC converters -- we commonly use 6 , 9, and 12 phase inputs to VFDs to reduce pulse current and related harmonics its worth it when the utility wont allow you to exceed prescribed levels.

So it is not as uncommon as one might imagine !

Jon

Line Balancing is easy.

Hii..

Here is the Answer for u r Quistion..

The Generator's Armature rotates 360 degree arround the winding(Core) thats the reasion the Phase angle is defined as 120 Degree per phase

so 120 x 3 = 360 degree..

that is the reasion we will get 3 phase only...

That is how it is realised: 3 fazes spread over the rotation of a generator produce 3 sinuses nicely 120° shifted.

Imagine that Tesla would have decided that 3 was not enough and to go for 4 or 5.

5 would have been a very reasonable number to go for as it is a prime figure. We mechanical engineers like those prime figures.

The faze shift would have been 90 or 72°, resulting in completely different ways of multi-faze calculations.

Now you have the main voltage between faze and neutral.

Between fazes you will find the main voltage * SQRT(3). Easy and you can't be wrong.

Imagine 4 fazes: you will have between fazes different voltages: between 1 and 2 you will find main * SQRT(2); 1 and 3 will give you Main * 2 and 1 and 4 will result in main * SQRT(2).

Try to figure it out in a 5f system.

Someone had to make a decision when he made the first generator to drive a motor. Luckily he was smart and knew how to design a decent system.

Gwen

When Tesla had his vision in which he conceived his rotating magnetic field, he correctly assumed that a 3-wire system would be the simplest. He built his alternator and motor system to prove his theory which worked first time out of the box. He convinced Westinghouse that AC was the way to go even though the DC industry (Edison) tried to convince everyone through the media that AC was much more dangerous. Anyway, Westinghouse hired Tesla to design the 3-phase power generation system that was used a Niagra Falls and AC transmission took off.

BTW, regarding phase rotation in motors, reversing any two wires will reverse the rotation.

Kyoto,

While Tesla held patents in the 60 Hz polyphase generation, distribution, and use of alternating current, the first generators of his at Niagara Falls were in fact two (2) phase machines. Three phase generators followed. Why he initially chose 2 phase is not clear at least according to the sources available to me, and I was unable to find the phase angle/configuration in a quick search.

Two phase power of several configurations was later used in some specialized applications, and also was distributed in some rural areas as a means to lower transmission wiring costs to farms in sparsely populated areas, in which case the third phase was "synthesized" at the point of use when necessary.

Regards, Greg

3 phase and 360 degrees rotation combined with even number of poles in a generator mathematically works out perfect including 60 cycle Ac....

Remember the magic of 1.73 too.

JL.

The simplest explanation is that three phases are all that are needed to cause rotations of motors in the desired direction. One phase won't do it without phase-shifting capacitors, and two phases won't do it without phase shifting capacitors either (if they're 180 degrees out of phase, that is).

I build resistance heating systems for studio glass artists. I have a 40kw system on Strawberry St in Philadelphia Pa that HAD to be built as a single phase machine because no three phase is available. Turns out that that part of Philly has the last vestiges of the original two phase Tesla electrification scheme.

Interesting. My Dad was a stained glass artist and had a bunch of ovens to fire the glass and slowly anneal them down to ambient.

Taught me the trade, but I never practiced it much.

Tesla's most famous contribution was to the "Philadelphia Experiment". The weight of evidence interference confirms that this incident did occur - it is only the claims of the alleged side effects and results which muddy the waters and has caused the issue to be suppressed.

Fleming's work was the major contribution to Motor and Generator work leading to Fleming's Generator and Motor Rules.

In theory you can generate and motor in is as many phase as you wish but to maintain a magnetic and dynamic balance the combination is limited (i.e. 3,4,6,8,9,12,) I'm not good at maths so somebody will need to work out the equation to infinity. Such situation would alter the generator poles and altering the poles changes the frequency so it all gets a bit too overwhelming to consider.

I doubt he made any contribution to it. The weight of evidence says it did not take place. There is a large body of speculation with zero supporting evidence that makes it an ongoing source of speculation.

Think about it, of they could do this they would do it now in a better way and it would be commonplace. Why do an experiment, achieve sucess and say lets not do that again, it would give us a winning secret method against the Axis powers...and we do not want that.

I apologise for digressing from the core question. There is documented evidence to show that Tesla attempted to progress Eisenstein's theory of the Unified Field and attempted to put this into practice on a ship experiment in Philadelphia during the war.

By coincidence the USS Eldridge was recorded at Philadelphia with a recorded discrepancy in its commissioning documents. It is also strange that this ship - less than two years old was given to Greece after the war in a substantially lighter condition that that records on its original ship yard commissioning documents, without any notable absence of its naval or marine equipment. With Greek eye witnesses confirming abnormal heavy cable strung around the ship. The proven false and incorrect US navy records for this vessel does nothing but give way to speculation.

It is therefore accepted that the US Eldridge did take part in some pre US Navy ownership experiment or trial which the authorities failed to acknowledge.

As to future development nobody really knew what if any the "success" was. Similar to the Atom bomb project where many people subsequently died from effects of working on the project, it is alleged that the result of this experiment, irrespective of the material success were more immediate and too damaging to humans and could not be controlled. It is just possible, whatever the circumstances that this project was closed indefinitely.

The authorities were more than happy to see this issue spiral into a Bermuda Triangle type paranoia cult as it diverted real investigations into the anomalies and true nature of the project.

Tesla's history, his location in 1943, and corroborated eye witness accounts cannot be dismissed and unlike the movies we know that the characters, the places, and players, are real its just the true story we don't know.

I think they were using that cable to deal with magnetic mines and torpedoes, to create a field to detonate them from afar.

this is different from degaussing that tried to creat a zero mag signature

They kept that secret

Since Tesla died on 7 Jan 1943, he must have teleported aboard from his past. That wasn't documented either <VBG>

Sorry - that should have read "in 1942", having worked on the project since the late 30s, he resigned from the project in March 1942, handing over to his contemporary - Von Neumann, and as you say died in early 1943 before witnessing the Eldridge trial.

There is no technical problem for a 5 pole system.

It would only bring more wires and potential errors.

There are a lot of multipole systems: slow rotating generators have multipole rotors.

The slower a machine runs, the longer it will live, but also the more expensive it becomes for the same amount of energy that it generates.

We are back at the level of 3 phazes being sufficient, why do more.

From where does the difference of 50 and 60 Hz come?

I think the first AC in North America was 25Hz and the eurpoeans doubled it to save iron and copper in their later electrification. North America did the same. Whey they settled on 60 vs 50 ?

here are some comments about that

http://services3.ieee.org/organizations/pes/public/2003/sep/peshistory.html

They should have gone to 400 hertz, but as you go up in frequency phase control on a grid gets harder

In the UK, the 50 cycles per second frequency was derived from the limitations of the prime mover of the generating set set. The standard RPM of the nations power stations generators was set at 3000 rpm.

For a standard two pole generator that results in exactly 50 cycles per second (Hz).

Altering the frequency output of the generator itself requires either the shaft speed to be changed or the number of poles in the generator to be changed.

Thats why you would not find a national 5 phase machine as you eluded to earlier.

A 3 phase (two pole) machine has 6 poles in total