A low speed rotary such as the Victor Wolf approx 190 rpm would be ideal or scrubbing. If you use Charly Pads in your carpet cleaning then you may have a Wolf or similar machine already.
Medium speed machines such as the Sprite runs at 250 rpm and would be OK for scrubbing as well as burnishing.
You can then go to machines that operate at 400 rpm or higher for burnishing work.
Chris