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 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. <EOS>