Revolve command option Deformable=Yes will result in a non-rational surface.

http://docs.mcneel.com/rhino/6/help/en-us/index.htm#commands/revolve.htm

*Deformable = Yes*

*The surface is rebuilt on the ‘around’ direction to a degree-3 non-rational surface. Specify how many points in that direction. Deformable revolves can be deformed smoothly with point editing.*

*Deformable = No*

*The resulting revolved surface is an exact revolve: a rational surface with fully-multiple knots at the quadrants. This kind of surface is not easy to deform smoothly by point editing.*

Circle and Arc commands do not appear to have an option for non-rational results.

Rebuild or RebuildUV will convert a rational cuve or surface to a non-rational cuve or surface. The conversion will not be exact because a circle or arc cannot be exactly represented (no deviation) by a non-rational NURBS curve/surface. However the deviation from exact can be minimized by increasing the number of points - more points results in less deviation. A circle rebuilt as a degree 3 curve with 8 control points has a maximum deviation of 0.11% of the radius. With 16 control points the deviation is 0.006% of th radius.