Enclosed Fan Cooled Induction Motor Research Articles

Definition and Experimental Validation of a Second-Order Thermal Model for Electrical Machines

This article proposes a second-order thermal model useful to predict the average winding temperature of electrical machines used in electrical drives. Both analytical and practical considerations are provided. The proposed model is first described, including the physical meaning of each thermal parameter. Then, an experimental procedure to properly calibrate the thermal parameters of the proposed model is presented in detail. Later, experimental results providing the validation of the proposed thermal model both in transient and steady-state thermal conditions are presented, including their in-depth analysis. Although the proposed thermal model is calibrated and validated on a totally enclosed fan cooled induction motor, it has general validity, such that it can be adopted for any electrical machine, regardless of windings type, e.g., distributed or concentrated. The simplicity of the proposed thermal model and its high accuracy in estimating the average winding temperature make it useful in electric drives, e.g., its implementation on motor control algorithms to perform proper overload strategies.

Stator Winding Second-Order Thermal Model including End-Winding Thermal Effects

This paper proposes a second-order thermal model for electrical machines. The goal of this model is the prediction of the average winding temperature during short and long thermal transients up to the steady-state conditions. First, the thermal parameters of the electrical machine are determined by a DC test. Then, the proposed model is characterized and validated using AC tests. The accuracy of the proposed thermal model has been verified comparing the computed temperatures with the measured ones. The maximum error found during the thermal transient is lower than 3%, an excellent result comparing the complexity of a total enclosed fan cooled induction motor and the simplicity of the proposed model.

Induction Motor Equivalent Circuit Including the Stray Load Losses in the Machine Power Balance

In this paper, the stray load losses due to the air gap spatial harmonics effects on the rotor squirrel cage are considered and a simplified induction motor equivalent circuit able to include them in the machine power balance is reported. In the proposed model, an additional resistance appears in series with the stator impedance. This additional parameter has been defined on the basis of power balance considerations applied to the induction motor classical theory. The complete theoretical analysis together with the guidelines to measure the equivalent circuit parameters are reported in detail. Finally, the proposed approach has been experimentally verified using five total enclosed fan cooled induction motors.

Thermal Modelling of Induction Motors Based on Accurate Loss Density Distribution

The ability to predict the temperature rise of a machine prior to its construction is as important as the ability to predict its performance. For a complex heat flow systems, such as electrical machines, the lumped parameter network technique still plays a very important role for the solution of heat flow problems. This paper discusses the development of the thermal model, taking into account the different material types and complicated geometries within the machine, as well as the different modes of heat transfer. However, to predict an accurate temperature distribution requires the knowledge of loss distribution in the machine. Using the temperature-time method a more accurate loss distribution is obtained. The model performance is validated against measured results obtained for a 4 kW, 3-phase, 4-pole, 415 V totally enclosed fan cooled induction motor.