THEORETICAL VIBRATION ANALYSIS OF SOFT MOUNTED TWO-POLE INDUCTION MOTORS WITH STATIC ROTOR ECCENTRICITY

2011 ◽  
Vol 03 (01) ◽  
pp. 131-159 ◽  
Author(s):  
ULRICH WERNER
Keyword(s):  
Vibration Analysis ◽  
Magnetic Force ◽  
Induction Motors ◽  
Rotor Speed ◽  
Electromagnetic Excitation ◽  
Worst Case ◽  
Rotor Eccentricity ◽  
Soft Foundation ◽  
Stiffness And Damping ◽  
Film Characteristics

The paper shows a mathematical model for vibration analysis of soft mounted two-pole induction motors regarding electromagnetic excitation due to static rotor eccentricity. A static rotor eccentricity causes an electromagnetic force, acting on the rotor and on the stator and oscillating with the double supply frequency. This magnetic force is implemented into a simplified analytical machine dynamic model and the correlations between the rotor dynamics, electromagnetic, oil film characteristics of the sleeve bearings, and the stiffness and damping of a soft foundation are mathematically described. The derived results are clarified using an example that shows the influence of the rotor speed and the direction of the magnetic force on the vibration behavior. On one hand the aim of the paper is to show the mathematical correlations, based on a simplified model. On the other hand, the aim is to derive a method for calculating the forced vibrations — as a worst case — caused by a static rotor eccentricity. Therefore, the paper shall prepare the basis for implementing this method in more detailed numerical programs, e.g., finite element programs.

Online Speed Detection of Induction Motors Based on Tooth Harmonic

2011 ◽  
Vol 58-60 ◽  
pp. 2517-2521
Author(s):  
Qing Xin Zhang ◽  
Hai Bin Li ◽  
Jin Li
Keyword(s):  
Induction Motors ◽  
Rotor Speed ◽  
Motor Speed ◽  
Stator Core ◽  
Current Harmonic ◽  
Stator Current ◽  
Speed Measurement ◽  
Frequency Components ◽  
Air Gap Magnetic Field ◽  
Alveolar Surface

Many methods have been used to detect the motor speed. All of these methods are based on the parameter equation of motor and the detection results are influenced by parameters of induction motor more or less. The research of Speed Measurement method without of Motor parameters effect is very significant. Based on the harmonic generated in the air gap magnetic field by the stator core on the alveolar surface, directly by the analysis and testing of stator current harmonic, the rotor speed is detected which is proportional to the speed of frequency components. Experiment results show that this method is good, and the accuracy achieve a desired effect in real time.

Using Parametric Simulation to Optimize Suspension Design

2003 ◽  
Author(s):  
G. Walter Rosenberger ◽  
Peter E. Klauser ◽  
George P. Binns ◽  
Gary P. Wolf
Keyword(s):  
Control Unit ◽  
Cost Effective ◽  
Parameter Analysis ◽  
Ride Quality ◽  
Worst Case ◽  
Suspension Parameters ◽  
History Of ◽  
Vehicle Response ◽  
Stiffness And Damping ◽  
Test Result

A project to design and implement suspension improvements to Amtrak’s F-40 Non-Powered Control Unit (NPCU) cars is described. The cars, built from former F-40 locomotives, had a history of poor ride quality. Rail Sciences Inc. (RSI) inspected one of the cab cars and measured its ride quality. Peter Klauser modeled the vehicle in NUCARS™ and validated the model against the test data. The vehicle response was primarily in pitch and bounce modes. To optimize the suspension, Klauser simulated vehicle response for a range of four suspension parameters: primary stiffness and damping, and secondary stiffness and damping. Nearly 2600 suspension combinations were considered. Simulation file setup and data analysis were performed automatically using parameter analysis software interacting with NUCARS™. The result was a five-dimensional response contour for each output variable, such as the engineer’s seat vertical and lateral accelerations, and car body acceleration. The most cost effective stiffness and damping parameters were selected from the response contour and translated into component specifications. RSI then provided Amtrak with new axle box springs and dampers, and re-tested the vehicle. The test result closely followed the predicted results from the simulation. Engineer’s seat vertical and cab lateral accelerations improved by 42% and 32% respectively for the worst-case conditions in the test territory.

scholarly journals Nonlinear Vibration Analysis of Rotor considering Cogging and Harmonic Effects

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Shanle Li ◽  
Feng Liu ◽  
Hongyan Wang ◽  
Haijun Song ◽  
Kuilong Yu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Analysis ◽  
Magnetic Force ◽  
Rotor System ◽  
Kutta Method ◽  
Rotor Vibration ◽  
Motion Equations ◽  
Runge Kutta Method ◽  
Static Eccentricity ◽  
New Formula

This paper aims to investigate nonlinear vibration characteristics of rotor system considering cogging and harmonic effects. Firstly, relative permeance with eccentric was established and then corrected by correction factor caused by the cogging effect. Based on the new formula of relative permeance, the expression of unbalanced magnetic force was obtained, and the coefficient of cogging effect was defined. Motion equations of rotor system were established, and Runge–Kutta method was used to solve the equations. Results showed that errors between finite and analytical results were smaller considering cogging and harmonic effects. When the harmonics were taken into consideration, the vibration of rotor increases sharply. When the cogging and harmonics were taken into consideration simultaneously, the vibration of rotor decreased instead, which means that stator slots have the effect of reducing vibration in rotor system. Rotor vibration was axis symmetry with static eccentricity rather than central symmetry with no eccentricity, and double, four times, and six times supply frequency always existed in the components of main frequency with eccentric.

The Solution of Directed D-Axis Current for the Bearingless Induction Motors

2013 ◽  
Vol 779-780 ◽  
pp. 711-715
Author(s):  
Yan Jun Yu ◽  
Xian Xing Liu
Keyword(s):  
Time Delay ◽  
Magnetic Force ◽  
Induction Motors ◽  
Levitation Force ◽  
Dynamic Performance ◽  
Electromagnetic Torque ◽  
Direct Solution ◽  
Simulation Results ◽  
Stator Flux ◽  
Stator Flux Oriented

The control of nonlinear decoupling between the electromagnetic torque and radial levitation force is the key of the stable suspend operation of bearingless induction motor. An optimized algorithm for stator flux oriented control with direct solution of d-axis current is proposed. This method overcomes the problems that the conventional stator flux oriented control which must work with decouple regulator and is influenced by time-delay of decouple regulator. The control of suspend model imports the feedback control of unilateral magnetic-force to reduce the errors about the delay and interference of system. The simulation results show that the motor has excellent dynamic performance and stability.

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