Star/Delta Line/Phase Voltage/Currents

[BobRivers]

Hello,

Really struggling to get my head round the above can anybody please explain (in easy terms if possible) the difference between line and phase voltage?

Star connections with Balanced load relationship to each other IL=IP Delta Ul=UP?

My head is mince...............

Thanks

 

[topquark]

Line v Phase Voltage.

Assuming you understand the concept of phasing first. It's possible for a cable to carry two voltages that are in phase with each (they peak/trough at the same time). If you had 100V on phase 1 and 50V on phase 2. There would be two phase voltages, one 100V and one 50V (in real world systems these are normally chosen to be the same!). The line voltage in this case would be 150V (the vector addition of the two phase voltages).

 

[topquark]

The only difference with 3 phase is there are 3 phase voltages that are 120 degrees out of phase with each other. IE the second phase is starting it's cycle (pure sine wave ideally) when the first phase is 1/3 of the way through it's cycle.