Identification of Lamination Stack Properties: Application to High Speed Induction Motors

International audienceIn order to predict the lateral rotordynamics of a high-speed induction motor, an optimization procedure is used for identifying the dynamic behavior of the magnetic core made of a lamination stack, tie rods, and short-circuit rods. Modal parameters predicted by a finite-element model based on beam elements and measured on induction motors are included in modal error functions contained in a functional. The minimization of this functional by using the Levenberg-Marquardt algorithm permits extracting the equivalent constitutive properties of the lamination stack for several rotors of different sizes. Finally, the size effect on the constitutive properties identified is discussed

Self-balancing in Rotating Machinery

This project investigated the method of self-correcting mass imbalances in a rotor operating above its critical speed using multiple-ball balancer. This self-balancing phenomenon was described theoretically and a working model was designed and fabricated to demonstrate this principle. The device was used to test the ability of the balls to achieve stable balancing positions under different conditions including rotation speed, number of balls, addition of damping fluid, and critical speed of the system. The self-balancing was achieved for 2, 3, 4 and 8 balls, but inconsistently. The results are more consistent for the rotation speed above 2.5 times the critical speed. Damping fluid is shown to greatly help to stabilize the balls

Design of a high speed high power switched reluctance motor

PhD ThesisAn increase in the price of rare earth materials in 2009 prompted research into alternative motor technologies without permanent magnets. The SRMs have become more of an attractive solution as they are relatively simpler to construct than other machines technologies hence cost effective. Furthermore, the rugged structure of the rotor makes it suitable for high speed operation, if appropriately designed. This thesis investigates the design, analysis and prototype manufacture of an SRM, that from electromagnetic point of view, meets the power output of the PM machine used in the Toyota Prius, although operating at a higher speed of 50,000 rpm. As a result, the required torque is considerably less than an equivalent motor with the same output power running at lower speed, hence this approach allows for much smaller frame sizes. To achieve the required torque, careful choice of stator/rotor tooth combination, coil number of turns and number of phases is needed. Running at high speed, increases the AC copper loss (consisting of skin effect and proximity effects) and iron loss. These shortcomings are extensively discussed and investigated. The mechanical design of this motor requires careful consideration in order to minimise the high mechanical stresses acting upon the rotor, which are due to the high radial forces caused by the centripetal force at high speed. In order to address the mechanical constraints caused by the hoop stress, a structure common to flywheels is applied to the rotor. In this approach, the shaft bore is removed and the laminations are sandwiched together using cheek plates, which are secured using tie rods. The cheek plates have their extending shafts, which consequently will transfer the torque to the rest of the system. The proposed model is analysed for both the electromagnetic and mechanical aspects, successfully demonstrating a promising rotor topology for the design speed. A high speed motor design needs to take into account shaft design, rotor design and bearing design. The high speed operation of the salient rotor gives dramatic rise to the windage loss. These factors are carefully considered in this work and the results are presented

12th International Conference on Vibrations in Rotating Machinery

Since 1976, the Vibrations in Rotating Machinery conferences have successfully brought industry and academia together to advance state-of-the-art research in dynamics of rotating machinery. 12th International Conference on Vibrations in Rotating Machinery contains contributions presented at the 12th edition of the conference, from industrial and academic experts from different countries. The book discusses the challenges in rotor-dynamics, rub, whirl, instability and more. The topics addressed include: - Active, smart vibration control - Rotor balancing, dynamics, and smart rotors - Bearings and seals - Noise vibration and harshness - Active and passive damping - Applications: wind turbines, steam turbines, gas turbines, compressors - Joints and couplings - Challenging performance boundaries of rotating machines - High power density machines - Electrical machines for aerospace - Management of extreme events - Active machines - Electric supercharging - Blades and bladed assemblies (forced response, flutter, mistuning) - Fault detection and condition monitoring - Rub, whirl and instability - Torsional vibration Providing the latest research and useful guidance, 12th International Conference on Vibrations in Rotating Machinery aims at those from industry or academia that are involved in transport, power, process, medical engineering, manufacturing or construction

12th International Conference on Vibrations in Rotating Machinery

Since 1976, the Vibrations in Rotating Machinery conferences have successfully brought industry and academia together to advance state-of-the-art research in dynamics of rotating machinery. 12th International Conference on Vibrations in Rotating Machinery contains contributions presented at the 12th edition of the conference, from industrial and academic experts from different countries. The book discusses the challenges in rotor-dynamics, rub, whirl, instability and more. The topics addressed include: - Active, smart vibration control - Rotor balancing, dynamics, and smart rotors - Bearings and seals - Noise vibration and harshness - Active and passive damping - Applications: wind turbines, steam turbines, gas turbines, compressors - Joints and couplings - Challenging performance boundaries of rotating machines - High power density machines - Electrical machines for aerospace - Management of extreme events - Active machines - Electric supercharging - Blades and bladed assemblies (forced response, flutter, mistuning) - Fault detection and condition monitoring - Rub, whirl and instability - Torsional vibration Providing the latest research and useful guidance, 12th International Conference on Vibrations in Rotating Machinery aims at those from industry or academia that are involved in transport, power, process, medical engineering, manufacturing or construction

5.Uluslararası Öğrenciler Fen Bilimleri Kongresi Tam Metin Kitabı

Çevrimiçi (IX, 431 Sayfa; 26 cm.)

Feasibility study of Unmanned Aerial Vehicles (UAV) application for ultrasonic Non-Destructive Testing (NDT) of Wind Turbine Rotor Blades. Preliminary experiments of handheld and UAV utrasonic testing on glass fibre laminate

In this thesis, we have conducted a feasibility study on UAV application for ultrasonic pulsed non-destructive testing of wind turbine rotor blades. Due to the high initial cost of wind turbines, and their decreasing availability due to increasing size and offshore locations, it is imperative to properly maintain these structures over their 10-30-year lifetime. Operation and maintenance costs can account for 25-30% of the overall energy generation costs (MartinezLuengo, et al., 2016), where the wind turbine rotor blade can be considered the most critical component, accounting for 15-20% of the manufacturing costs. Thus, an increase in O&M efficiency of wind turbine rotor blades through condition monitoring can yield substantial financial benefits. Currently, Unmanned Aerial Vehicles (UAV) are in use for visual and thermography inspection of wind turbines. These techniques for structural condition monitoring does have serious limitations, as the condition of internal components in blades, built from glass fibre laminates, cannot be visually inspected. However, pulsed ultrasonic echo technique have proven highly efficient for wind turbine rotor blade inspection. The ultrasonic transducer requires surface contact with the examined material, and we investigated the potential of UAV implementation for fast, safe and reliable measurements of wind turbine rotor blades. This feasibility study investigates the applicability of ultrasonic testing of glass fibre laminates, specifically glass fibre produced by Lyngen Plast A/S. Firstly, we conducted handheld ultrasonic tests on simulated delamination defects, looking for damage indications on a voltage-time graph. Secondly, we induced damage on a 27mm thick sample through a 3-point bending test and measured the echo response from the ultrasonic pulse. The second experiment was repeated using a Storm AntiGravity UAV, producing promising results with preliminary instrumentation. A significant challenge to the feasibility of this study was the operational risks. We carried out a preliminary and qualitative risk assessment of the intended UAV operation by using the SWIFTanalysis and Bow-Tie method. The results were two important risk-mitigating measures. Risk reductive: “Design UAV for impact with wind turbine rotor blades,” and risk preventive: “Develop statistical data on wind conditions at wind turbine site, calculate low-risk dates for flight.” The implementation of the said measures, quality of our results, experiences from the UAV flight and concept considerations are presented throughout this paper. In the end, a conclusion is drawn and topics for future studies is presented

Upgraded automotive gas turbine engine design and development program, volume 2

Results are presented for the design and development of an upgraded engine. The design incorporated technology advancements which resulted from development testing on the Baseline Engine. The final engine performance with all retro-fitted components from the development program showed a value of 91 HP at design speed in contrast to the design value of 104 HP. The design speed SFC was 0.53 versus the goal value of 0.44. The miss in power was primarily due to missing the efficiency targets of small size turbomachinery. Most of the SFC deficit was attributed to missed goals in the heat recovery system relative to regenerator effectiveness and expected values of heat loss. Vehicular fuel consumption, as measured on a chassis dynamometer, for a vehicle inertia weight of 3500 lbs., was 15 MPG for combined urban and highway driving cycles. The baseline engine achieved 8 MPG with a 4500 lb. vehicle. Even though the goal of 18.3 MPG was not achieved with the upgraded engine, there was an improvement in fuel economy of 46% over the baseline engine, for comparable vehicle inertia weight

AGT (Advanced Gas Turbine) technology project

An overall summary documentation is provided for the Advanced Gas Turbine Technology Project conducted by the Allison Gas Turbine Division of General Motors. This advanced, high risk work was initiated in October 1979 under charter from the U.S. Congress to promote an engine for transportation that would provide an alternate to reciprocating spark ignition (SI) engines for the U.S. automotive industry and simultaneously establish the feasibility of advanced ceramic materials for hot section components to be used in an automotive gas turbine. As this program evolved, dictates of available funding, Government charter, and technical developments caused program emphases to focus on the development and demonstration of the ceramic turbine hot section and away from the development of engine and powertrain technologies and subsequent vehicular demonstrations. Program technical performance concluded in June 1987. The AGT 100 program successfully achieved project objectives with significant technology advances. Specific AGT 100 program achievements are: (1) Ceramic component feasibility for use in gas turbine engines has been demonstrated; (2) A new, 100 hp engine was designed, fabricated, and tested for 572 hour at operating temperatures to 2200 F, uncooled; (3) Statistical design methodology has been applied and correlated to experimental data acquired from over 5500 hour of rig and engine testing; (4) Ceramic component processing capability has progressed from a rudimentary level able to fabricate simple parts to a sophisticated level able to provide complex geometries such as rotors and scrolls; (5) Required improvements for monolithic and composite ceramic gas turbine components to meet automotive reliability, performance, and cost goals have been identified; (6) The combustor design demonstrated lower emissions than 1986 Federal Standards on methanol, JP-5, and diesel fuel. Thus, the potential for meeting emission standards and multifuel capability has been initiated; (7) Small turbine engine aerodynamic and mechanical design capability has been initiated; and (8) An infrastructure of manpower, facilities, materials, and fabrication capabilities has been established which is available for continued development of ceramic component technology in gas turbine and other heat engines