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Electromagnetic Principles of Switched Reluctance Machines
Published in Berker Bilgin, James Weisheng Jiang, Ali Emadi, Switched Reluctance Motor Drives, 2019
Windage in a rotating machine is the resistance of air against the motion of the rotor. Windage power loss increases exponentially with the rotational speed or the radius of the rotor. Especially in high-speed operation, windage losses can be significant in SRMs due to the salient pole structure. In order to reduce the windage losses, the air gap between rotor poles can be filled with epoxy resin to create a smooth rotor surface. Smooth rotor surface has much lower friction, and this results in lower windage power loss and windage noise [7].
Windage of Rotating Polygons
Published in Gerald F. Marshall, Laser Beam Scanning, 2017
It is a corollary of any object moving or rotating in a fluid medium that it will consume power. The power losses in a rotating mirror scanner are those associated with the drag of the spin axis bearings and the windage of the rotating polygon. In addition, there will be further losses in the drive motor. Of these, windage is not only often the largest component, but it can be altered substantially by seemingly small changes in configuration. Some of the benefits of decreasing the windage power losses are reduced total power input, smaller motor and drive supply, and lower running temperatures or, alternatively, higher possible rotational speeds for the same power input.
Motor Power Losses
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Windage in a rotating electric machine is defined as the resisting influence of fluid (air or liquid) against not only rotating but also stationary components, creating power losses. In an electric motor, the windage power loss Pw increases exponentially as a function of the rotor rotating speed ω and the rotor radius rr. In practice, windage losses of electric motors are very important in the motor design and optimization, primarily consisting of the following components: The friction loss due to the viscous shear effect in the fully developed turbulent flow. It was reported that such a loss could be up to 30% of the total windage loss.The dynamic loss (or rotor body loss in some references) due to driving air in the airgap. The dynamic loss depends strongly upon the thermophysical properties of air such as density and viscosity and, in turn, the air temperature in the rotor–stator airgap.The loss associated with the stator slots with unfilled openings. The penetration of the airflow into the slot openings and the formation of the flow recirculations in such slot openings can have a complicated influence on energy loss.The loss associated with the roughness on rotor surfaces.The windage loss of some motor components such as fans.The ventilation path loss.
Vector-Controlled Dual Stator Multiphase Induction Motor Drive for Energy-Efficient Operation of Electric Vehicles
Published in IETE Journal of Research, 2023
M. Sowmiya, S. Hosimin Thilagar
Transient analysis and high-performance drive control such as vector control are initiated by the development of a dynamic model [39,40]. Modeling a DSMIM necessitates the consideration of the following assumptions: (i) isolated and sinusoidal distribution of stator windings, (ii) negligible saturation, (iii) negligible effect of eddy current, friction and windage losses and (iv) uniform air gaps [41]. Since the two stators are electrically isolated two sets of d-q equivalent circuits are framed for analysis and, therefore, two sets of d-q modeling equations are obtained under a common reference frame. For simplicity in analysis the dual stator d-q voltage and d-q current equations are derived under the stator reference frame. It is then followed by the development of stator and rotor flux linkage expressions. The model outputs five-phase stator current, torque and speed. The direct and quadrature components of the inner stator current are obtained by Equations (3) and (4), respectively. The direct and quadrature components of the outer stator 2 current are obtained by Equation (5) and Equation (6), respectively. Later the d-q stationary current components of the two stators are converted into their equivalent five-phase components using Inverse Clark’s transformation.
Evaluation of in-pipe turbine performance for turbo solenoid valve system
Published in Engineering Applications of Computational Fluid Mechanics, 2018
On the other hand, a pressure loss of 28.3 kPa was measured in experimental studies with a calibration uncertainty of ±3.5% and equipment accuracy of 0.2%. This value was predicted as 6.3 kPa in the CFD studies. This difference is due to local losses in pipes which was not taken into account in CFD runs. When the turbine is taken off the line, the pressure loss of the pipe is measured as 20.1 kPa. In this case, the pressure loss due to the turbine is calculated as 8.2 kPa. This difference between the CFD and the experimental studies is thought to be caused by surface and windage friction on the turbine.
Genetic Algorithm & Fuzzy Logic-based Condition Monitoring of Induction Motor Through Estimated Motor Losses
Published in IETE Journal of Research, 2023
G. S. Ayyappan, B. Ramesh Babu, M. Raja Raghavan, R. Poonthalir
The segregated motor losses are estimated at any given load condition. To diagnose the faults, the losses are to be projected to full load conditions. The losses at full load & rated voltage conditions are estimated using the Equations (11)–(14). The windage and friction loss does not vary much with the load; hence it is kept constant.