Method for stopping a vacuum pump

A method of stopping a rotor 7 of a vacuum pump rotating at an operational RPM from which the rotor cannot be coasted down to zero RPM without a relatively high probability of the rotor and stator 8, 9 clashing, and a vacuum pump comprising a controller 10 configured to carry out the method. The method comprises rotating the rotor at an intermediate RPM at which there is substantially no probability of clashing for a dwell time sufficient for the pump to be at or below a threshold temperature, the intermediate RPM being at or below a threshold RPM which is below the operational RPM, and subsequently coasting down the rotor until cessation. The threshold RPM is the maximum speed at a thermal steady state wherein the rotor can be coasted down until it stops with substantially no probability of the rotor and stator clashing, and the threshold temperature is the temperature of the pump when the rotor is at the threshold RPM at a thermal steady state.