I don't get something about this diagram. The conductors are supposed to be coils, but they just look like wires going in or out of the page to me. I can't physically imagine where the coil is and how it goes round and round. Like how does the coil go to attach one pole to the other?

Like is the conductor going out of the page and jumping back into the page to make the coil? Because if it is, it still seems just like a single loop of wire rather than a coil.

http://www.ece.ualberta.ca/~knight/e.../f_ac_gen.html

 

I assume you mean the diagram at http://www.ece.ualberta.ca/~knight/e...s/f_ac_3p.html as there was none at the URL you quoted. If so, these diagrams are merely representations of how the 3 phase connections are made. There are 2 different configurations, star (or wye) and delta. Each leg with the rectangle drawn on it represents a field and could represent any number of coils, although it is easiest to understand if you think of each rectangle being just one coil.

Each coil has a 'start' and 'finish'. In the star configuration, all 3 'starts' are connected together at a common point, and 3 phase power is taken from the 3 'finish' leads. In the delta configuration, the coils are connected start-finish, start-finish, start-finish. The 3 phase power is taken from these 3 connections.

Both configurations produce the same amount of power, but the star provides less current and more voltage and vice-versa for the delta.

Hope this helps

 

Yes. I agree it is a confusing picture if you dont know already what it is trying to show you.

He is starting with just a 1 turn coil, and when you read on he puts in multi-turns later in his maths.

JimB

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Are you talking abt:
http://www.ece.ualberta.ca/~knight/e..._rotation.html

I can see where you are coming from but when you deal with a 3D object BUT you need to represent it in the 2D plane what can you do?

the main piece of infomation is where the teeth are on the stator so they get represented. The only bit of infomation that is required (from a coil P.O.V.) is where the coil goes in and where it comes out (then imagine the end-winding linking the two abt in inch abt the paper)

the dot & cross notation will show you the route, how many turns... does it really matter from this picture? no, the more turns just increases the Amp-turns that is produced but they still follow the same route, you could have one single turn with 1million amps or 1million turns with a single amp to get the same effect, so make the drawing simpler and show it as one turn

later on when you start getting into specific infomation (and when you start getting detacted from the physical and more mathematic) then the # of turns becomes important

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Once a problem is realised, the rest is just details

 

Heh, turns out that a 4-pole system is easier for me to get because of the more obvious way that the coils are made physically. Thanks all.