The phases have a phase shift of 120 degress - called electrical phase angle, meanwhile the windings on the motor are also shifted by 120 deg - mechanical angle. 
In a such way, when the current passes trough windings the rotating magnetic field is formed, which is the sum of all three vectors. This is the principle of induction motor that Nikola Tesla made 130 yrs ago.

If you simply swap two wires, the magnetic fieled changes the direction of rotation.

How to change rotation direction of 3-phase electrical machines?
My goal is to access the button and make the visibility to false from another class in vb.net

Dim obj = New MyClass()
obj.btnName.Visible = False


But it is throwing error as "Object reference not set to an Instance"
