A method for determining loss of load to an electrical motor by detecting load of a rotary electrical motor, the electrical motor being connected to or comprising a rotary speed controller, the electrical motor comprising a rotor comprising magnetic poles (140a, 140b, 140c 140d) and a stator comprising magnetic poles (180a, 180b, 180c, 180d) and a sensor, the sensor being arranged to measure a rotational speed of the rotor, the method comprising the steps of; ensuring that the motor is in a steady state of operation using the rotary speed controller, determining a real-time input of the rotary speed controller to the motor, characterised in that the method further comprises, in order to determine whether or not a load has been lost: setting the rotary speed controller in an open loop control state in which the determined real-time input of the rotary speed controller to the motor is used to control the motor, thereby setting the motor in an assumed steady state of operation with an assumed constant rotational speed, repeatedly measuring a rotational speed of the rotor, thereby repeatedly determining a rotational speed of the motor, and evaluating variations in the determined rotational speeds of the motor, wherein evaluating variations involves a determination of differences between different measurements of the rotational speed of the rotor, and if said variations are larger than or differs from an expected variation more than a first pre-determined threshold value conclude that a load is present. ensuring that the motor is in a steady state of operation using the rotary speed controller, determining a real-time input of the rotary speed controller to the motor, characterised in that the method further comprises, in order to determine whether or not a load has been lost: setting the rotary speed controller in an open loop control state in which the determined real-time input of the rotary speed controller to the motor is used to control the motor, thereby setting the motor in an assumed steady state of operation with an assumed constant rotational speed, repeatedly measuring a rotational speed of the rotor, thereby repeatedly determining a rotational speed of the motor, and evaluating variations in the determined rotational speeds of the motor, wherein evaluating variations involves a determination of differences between different measurements of the rotational speed of the rotor, and if said variations are larger than or differs from an expected variation more than a first pre-determined threshold value conclude that a load is present. setting the rotary speed controller in an open loop control state in which the determined real-time input of the rotary speed controller to the motor is used to control the motor, thereby setting the motor in an assumed steady state of operation with an assumed constant rotational speed, repeatedly measuring a rotational speed of the rotor, thereby repeatedly determining a rotational speed of the motor, and evaluating variations in the determined rotational speeds of the motor, wherein evaluating variations involves a determination of differences between different measurements of the rotational speed of the rotor, and if said variations are larger than or differs from an expected variation more than a first pre-determined threshold value conclude that a load is present.