High-Frequency Motor Modelling: Parameter Variation due to Manufacturing

In this paper, high-frequency (HF) modelling of electric machines with random wound distributed windings is investigated to highlight the parameter variation due to the manufacturing. HF modelling of electric machines can be performed by impedance measurements of the stator windings. The random wound windings introduce variability in the motor model limiting parameter estimation accuracy. These parameters are the following: series resistance, main inductance, skin effect and capacitive coupling of individual turns in the windings and from the windings to the frame. By measuring the impedance of the 3-phase windings of seven consecutively produced induction motors the variability due to the random wound windings can be studied. These seven motors are then compared to one another and to an eighth motor that was produced at a different point in time. From this it is illustrated that the behavior varies even when motors were produced consecutively.