Resistance determination in an electric motor assembly

Title: Resistance determination in an electric motor assembly Abstract A electric motor assembly is configured to determine a motor Winding resistance value, which depends on temperature, for operations like filtering false ripples during ripple counting based motor revolution measurement, or motor Winding temperature measurements. Predicted values of the motor resistance are determined for a first and second position of motor commutator sections relative to the motor brushes. The predicted values are based on a temperature value measured by the temperature sensor and a predetermined dependence of variation of the motor resistance dependent on the temperature value, at least one of the brushes contacting different numbers of the sections in the first position and the second position respectively. An electric motor current value is measured by a current sensor When the electric motor is at least substantially at standstill. A selection is made between different factors for determining the motor resistance value using the electric current value, dependent on Which of the predicted values of the motor resistance most closely corresponds to the electric current value. The motor resistance is determined using said electric current value according to the selected factor. Fig. 1