Understanding Three Phase Circuits: Direction of Arrows

[ranju]

In the given figures , what does the arrows denote , I mean what direction ??
V_nR is upward in 1st fig. , V_nR is towards left in 2nd fig. ( n is neutral here ) while in 3rd the line voltages are in anti-clockwise direction..!
I wanted to know the pupose of this and why these directions only??

 

[n.karthick]

In the given figures , what does the arrows denote , I mean what direction ??
V_nR is upward in 1st fig. , V_nR is towards left in 2nd fig. ( n is neutral here ) while in 3rd the line voltages are in anti-clockwise direction..!
I wanted to know the pupose of this and why these directions only??

The arrow denotes the sign of voltage induced in the winding when current flows in that direction. For example if current flows from terminal n to R, the voltage across the winding denoted by V_nR is positive.

 

[ranju]

This means it is not a particular rule we can take this in opposite direction too ??
And what about the anti-clockwise direction of line voltages (V_YR ,, V_BY..) ??