scholarly journals Mechanical stress and deformation in the rotors of a high-speed PMSM and IM

2021 ◽  
Author(s):  
Martin Enno Gerlach ◽  
Maximilian Zajonc ◽  
Bernd Ponick
Keyword(s):  
Mechanical Stress ◽  
Elastic Deformation ◽  
High Speed ◽  
Mechanical Load ◽  
Fem Simulation ◽  
Electric Machine ◽  
Test Machine ◽  
Test Speed ◽  
Rotor Surface ◽  
Traction Drives

AbstractHigh-speed electric machines are gaining importance in the field of traction drives and aviation due to their high power density. The evaluation of the mechanical stress in the rotor is one crucial part in the design process for this type of machines. The mechanical stress cannot be measured directly. Accordingly, a validation of the calculated mechanical stress is difficult and normally not performed. Instead of the mechanical stress, the deformation at the rotor surface can be measured using a spin test machine with distance sensors. The deformation can then be used to validate the calculation results.In this paper, the mechanical load exerted on an IM rotor for a $60\,\text{kW}/20000\,\frac{1}{\text{min}}$ 60 kW / 20000 1 min high-speed electric machine and an PMSM rotor for a $75~\text{kW}/25000\,\frac{1}{\text{min}}$ 75 kW / 25000 1 min high-speed electric machine is analysed in detail. The mechanical stress and the deformation are calculated and analysed using a FEM simulation model. Then, a spin test is performed on the two rotors. First, the burst speed is determined by operating two rotor samples above their defined test speed. Then, the deformation is measured at the rotor surface for different operating speeds and the defined test speed. The measurement and the simulation results are compared and discussed.It can be shown that the two designs do not exceed the maximum mechanical stress for the defined operating range. In the deformation measurement of the IM rotor, a plastic deformation up to $\varepsilon _{\text{IM, pl}} = 8$ ε IM, pl = 8  μm and elastic deformation up to $\varepsilon _{\text{IM, el}}=22$ ε IM, el = 22  μm can be seen. In regards to plastics, PMSM rotor expands up to $\varepsilon _{\text{PMSM, pl}}= 5$ ε PMSM, pl = 5  μm. The maximum elastic deformation of the PMSM rotor is $\varepsilon _{\text{PMSM, el}}=40$ ε PMSM, el = 40  μm. The comparison of the calculated and the measured elastic deformation shows good accordance for the two rotor types. Both models are capable of describing the deformation and the state of stress in the rotors. In burst tests, both rotors withstand rotational speeds far above the defined test speed.

scholarly journals Experimental Investigation of Spur Gear Efficiency

2007 ◽  
Author(s):  
T. T. Petry-Johnson ◽  
A. Kahraman ◽  
N. E. Anderson ◽  
D. R. Chase
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Mechanical Load ◽  
Spur Gear ◽  
Total Power ◽  
Test Machine ◽  
Gear Mesh ◽  
Test Methodology ◽  
Gear Efficiency ◽  
Accuracy And Repeatability

In this study, a test methodology was developed for measurement of spur gear efficiency under high-speed and variable torque conditions. A power-circulating test machine was designed to operate at speeds to 10,000 rpm and transmitted power levels to 700 kW. A precision torque measurement system was implemented and its accuracy and repeatability in measuring torque loss in the power loop was demonstrated. Tests were conducted on gears with two values of module, and two surface roughness levels, operating in a dry sump jet-lubrication environment with three different gear lubricants. These tests were used to quantify the influence of these parameters on load-dependent (mechanical), load-independent (spin), and total power loss. Trends in mechanical gear mesh efficiency and total gearbox efficiency were discussed in terms of rotational speed and transmitted torque. Finally, recommendations were made for the design of spur gear pairs, surface roughness, and lubricant selection for improved efficiency.

scholarly journals An Experimental Investigation of Spur Gear Efficiency

2008 ◽  
Vol 130 (6) ◽  
Author(s):  
T. T. Petry-Johnson ◽  
A. Kahraman ◽  
N. E. Anderson ◽  
D. R. Chase
Keyword(s):  
Surface Roughness ◽  
High Speed ◽  
Mechanical Load ◽  
Spur Gear ◽  
Total Power ◽  
Test Machine ◽  
Gear Mesh ◽  
Test Methodology ◽  
Gear Efficiency ◽  
Accuracy And Repeatability

In this study, a test methodology was developed for the measurement of spur gear efficiency under high-speed and variable torque conditions. A power-circulating test machine was designed to operate at speeds to 10,000rpm and transmitted power levels to 700kW. A precision torque measurement system was implemented, and its accuracy and repeatability in measuring torque loss in the power loop was demonstrated. Tests were conducted on gears with two values of modules and two surface roughness levels, operating in a dry sump jet-lubrication environment with three different gear lubricants. These tests were used to quantify the influence of these parameters on both load-dependent (mechanical), load-independent (spin), and total power loss. Trends in mechanical gear mesh efficiency and total gearbox efficiency were discussed in terms of rotational speed and transmitted torque. Finally, recommendations were made for the design of spur gear pairs, surface roughness, and lubricant selection for improved efficiency.

Rotordynamic Performance of a Rotor Supported on Bump Type Foil Gas Bearings: Experiments and Predictions

2006 ◽  
Vol 129 (3) ◽  
pp. 850-857 ◽  
Author(s):  
Luis San Andrés ◽  
Dario Rubio ◽  
Tae Ho Kim
Keyword(s):  
High Speed ◽  
Critical Speed ◽  
Load Capacity ◽  
Test System ◽  
Foil Bearings ◽  
Rotor Imbalance ◽  
Synchronous Motion ◽  
Damping Characteristics ◽  
Rotor Surface ◽  
Stiffness And Damping

Gas foil bearings (GFBs) satisfy the requirements for oil-free turbomachinery, i.e., simple construction and ensuring low drag friction and reliable high speed operation. However, GFBs have a limited load capacity and minimal damping, as well as frequency and amplitude dependent stiffness and damping characteristics. This paper provides experimental results of the rotordynamic performance of a small rotor supported on two bump-type GFBs of length and diameter equal to 38.10mm. Coast down rotor responses from 25krpm to rest are recorded for various imbalance conditions and increasing air feed pressures. The peak amplitudes of rotor synchronous motion at the system critical speed are not proportional to the imbalance introduced. Furthermore, for the largest imbalance, the test system shows subsynchronous motions from 20.5krpm to 15krpm with a whirl frequency at ∼50% of shaft speed. Rotor imbalance exacerbates the severity of subsynchronous motions, thus denoting a forced nonlinearity in the GFBs. The rotor dynamic analysis with calculated GFB force coefficients predicts a critical speed at 8.5krpm, as in the experiments; and importantly enough, unstable operation in the same speed range as the test results for the largest imbalance. Predicted imbalance responses do not agree with the rotor measurements while crossing the critical speed, except for the lowest imbalance case. Gas pressurization through the bearings’ side ameliorates rotor subsynchronous motions and reduces the peak amplitudes at the critical speed. Posttest inspection reveal wear spots on the top foils and rotor surface.

Seam Welds Modeling and Mechanical Properties Prediction in the Extrusion of AA6082 Alloy

2008 ◽  
Vol 367 ◽  
pp. 125-136 ◽  
Author(s):  
Lorenzo Donati ◽  
Luca Tomesani
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Fem Simulation ◽  
Die Design ◽  
Welding Parameters ◽  
Middle Section ◽  
3D Fem ◽  
Strain And Strain Rate ◽  
Mechanical Properties Prediction ◽  
Temperature Time

This work summarizes the outcome of recent research by the authors on modeling the formation of seam welds in aluminum extrusion and on evaluating the related mechanical properties on the final products. A profile with a seam weld in the middle section was produced with different die designs in order to investigate the relation between die design and local welding parameters, such as contact pressure, temperature, time of contact, strain and strain rate paths. The local welding conditions were evaluated by complete thermo-mechanical 3D FEM simulation of the processes. Specimens were extracted from the profiles and tensile tested, the resulting mechanical properties being discussed with respect to the local welding conditions. The possibility to adopt criteria for assessing the welding quality is discussed, together with the effect of high speed damage cracking.

Comparison of two Analytical Methods for Calculating the Maximum Mechanical Stress in the Rotor of High Speed Assisted Synchronous Reluctance Machines

2020 ◽  
pp. 1-1
Author(s):  
Iman Kleilat ◽  
Khadija El Kadri Benkara ◽  
Guy Friedrich ◽  
Stephane Vivier ◽  
Nazih Moubayed ◽  
...  
Keyword(s):  
Mechanical Stress ◽  
Analytical Methods ◽  
High Speed

scholarly journals Magneto- and Tensoresistance of the p Ge Compensated Crystals in the Range of Weak, Intermediate and Classically Strong Magnetic Fields

2016 ◽  
Vol 17 (1) ◽  
pp. 43-47 ◽  
Author(s):  
G.P. Gaidar
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Mechanical Stress ◽  
Elastic Deformation ◽  
Crystallographic Orientation ◽  
Longitudinal Axis ◽  
Mechanical Stresses ◽  
Strong Magnetic Fields ◽  
Compensation Factor

On the crystalsof compensatedp‑Ge (with the compensation factor of k = NSb/NGa = 0.5) the transverse (Н ^ (J // X)) magnetoresistance (within the magnetic fields of 0 < Н £ 22.3 kOe) at fixed values of the mechanical stresses Хі = 0; 0.2; 0.4; 0.6; 0.9; 1.1; 1.5 GPa were measured at 77 K. These mechanical stresses X created the elastic deformation along the samples, the crystallographic orientation of which coincided with the direction of [100]. Also at fixed magnetic field intensities Ні = 2; 4; 8; 10; 15; 20; 22.3 kOe the dependencies of resistivity  on the mechanical stress X, which coincides with the longitudinal axis of the crystal (X // J // [100]) and changes in the range of 0 £ Х £ 1.5 GPa, were measured. Last dependences characterized by the presence of a minimum in the range of X ~ 0.5 ¸ 0.6 GPa at the minimal magnetic field intensities Н = 2 kOe, which was shifted to the values of X ~ 0.2 ¸ 0.3 GPa with increasing Н up to 22.3 kOe.

Impact Tests in an Air-Water Mixture

2017 ◽  
Author(s):  
Aboulghit El Malki Alaoui
Keyword(s):  
High Speed ◽  
Volume Fraction ◽  
Optical Probe ◽  
Test Machine ◽  
Water Mixture ◽  
Air Bubble ◽  
Impact Tests ◽  
Void Fractions ◽  
Shock Test Machine ◽  
The Impact

Experimental impact tests were performed using a shock machine and aerated water by means of an air-bubble generator. High speed shock test machine allows carrying out tests of impact on water (slamming). This machine permits to stabilise velocity with a maximal error equal to 10% during slamming tests. The air volume fraction in the bubble was measured by optical probe technique. The present work is aimed at quantifying the effects of the aeration on the hydrodynamic loads and pressures during the entry of a rigid body at constant speed in an air-water mixture. The impact tests were conducted with a rigid pyramid for an impact velocity equal to 15 m.s−1 and for two average void fractions, 0,46% and 0,84%. The reduction of the impact force and pressure due to aeration has been confirmed by these experiments.

The Effect of Mechanical Stress and Surface Tracking of 22 kV Cable Spacer

2015 ◽  
Vol 1119 ◽  
pp. 769-774
Author(s):  
Nutsopin Nilbunpot ◽  
Amnart Suksri
Keyword(s):  
Epoxy Resin ◽  
Mechanical Stress ◽  
Mechanical Load ◽  
Tracking Performance ◽  
Electrical Field ◽  
Resin Sample ◽  
Pure Epoxy ◽  
Surface Tracking ◽  
High Electrical Field ◽  
Insulation Performance

Surface tracking is one of the causes that degraded the property of cable spacer. This research investigates about the mechanical stress and surface tracking performance of 22 kV cable spacer. Sample were tested according to the surface tracking under IEC 60587 standard under modified condition by and addition of the mechanical weight on the surface of pure epoxy resin sample. The mechanical load use were 0 kg and increase from 5 kg until 15 kg. The results showed that mechanical stress has affected the surface degradation of an insulation performance when the mechanical load is increased combined with high electrical field.

Performance Testing on Transonic Rotors

2010 ◽  
Vol 132 (08) ◽  
pp. 52-53
Author(s):  
Anthony J. Gannon ◽  
Garth V. Hobson
Keyword(s):  
Mach Number ◽  
Power Consumption ◽  
Flow Rate ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Performance Testing ◽  
Test Machine ◽  
Naval Postgraduate School ◽  
Scale Down ◽  
Limit Power

This article discusses the performance testing of transonic rotors at the Turbopropulsion Laboratory at the Naval Postgraduate School. The Mach number is one of the most important parameters in the case of high-speed compressors. In order to limit power consumption in a test machine, the simplest change is to scale down the machine. A second concept to reduce the power consumption of the machine once it has been scaled down is to throttle the flow before the rotor rather than after it. As a high-speed rotor compresses the incoming air by around 1.4–1.6 times, the air leaving it is appreciably denser than that coming in. If one throttles upstream of the rotor, the exhaust air leaves the machine at atmospheric pressure, which means that the incoming air is below atmospheric pressure. With upstream throttling, care has to be taken to provide long enough ducting ahead of the test compressor to present as uniform as possible flow after the flow rate measuring nozzle.

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