An atherectomy system includes an electric drive mechanism that is adapted to rotatably actuate an atherectomy burr and a controller that is adapted to regulate operation of the electric drive mechanism. The controller regulates operation of the electric drive mechanism in accordance with a power input limit value that limits how much power can be put into an atherectomy burr and an energy input limit value that limits how much energy can be put into the atherectomy burr. The controller may also regulate operation of the electric drive mechanism in accordance with a dynamic torque limit.