Induction Motor Shaft Research Articles

Исследование износостойких покрытий, нанесенных на образцы из конструкционной стали, применяемой для изготовления валов валопровода судов на подводных крыльях

Effective interaction of structural elements and materials from which they are made is one of the most important tasks in the design of parts and mechanisms of ship power plants. The operating experience of Meteor-type vessels has shown that the main cause of propeller shaft breakage and failure may be non-compliance with the technical requirements for the chemical-thermal processing of the shaft necks to the bearings size or poor-quality superficial coating. There has been made a comparative analysis of coating technologies, its results will significantly increase the cyclic wear resistance of the surface layer of the shaft necks of the hydrofoil ship shafting. The technologies of gas-plasma and gas-dynamic spraying, as well as electrospark alloying of the surface are considered. An instrumental assessment of the parameters of the applied protective coating quality is performed. Alloying materials for each of the methods of the surface hardening and modification are also presented. The scheme and design of the stand for testing the applied coatings for cyclic fatigue strength up to the moment of critical failure are given. The coatings deposited on the samples surfaces are studied to assess the surface microgeometry and microhardness. The samples are tested on the stand with a cyclic load at an induction motor shaft speed of 1800 rpm (30 rps). A bearing ball made of steel is used as an indenter. After testing, the focus of the coating destruction is assessed visually using a measuring and computing complex based on an optical microscope. As a result of the tests, it is revealed that the samples processed by the electrospark alloying method have the highest resistance to alternating cyclic effects, the lowest surface roughness and the highest microhardness.

Optimization and design analysis of 2-kW induction motor shaft by using Finite Element Analysis

The shaft is a very critical part of a 2-kW induction motor due to its function to support other vital components, such as the rotor, bearing, and casing. Finite Element Analysis (FEA) is used to analyze the shaft model. A meshing convergence test was conducted prior to the optimization. In which a mesh size of 0.5 mm and a tetrahedron shape are selected for the whole simulation to determine critical areas on the electric motor shaft (EMS). In this study, shaft optimization was conducted by using three manners in a sequential process, namely reducing the shaft seat for the rear bearing, modifying the step in front of the rear bearing, and then making the taper from the step in the previous process. This design modification was made to reduce the shaft mass and the maximum equivalent stress. At first optimization, namely replacing the rear bearing and its mount on the shaft, it succeeded in reducing the axle weight by 2,81%. However, the max equivalent stress increased from 30.347 MPa to 54.756 MPa which is located at the intersection of the stepped area, as well as deformation also increased from 0.002434 mm to 0.0026894 mm at the middle shaft. This drawback is overcome by changing the depth of the stepped area and creating a taper. In which the shaft mass can be reduced from 431.07 g to 408.20 g, as well as max equivalent stress is reduced from 54.756 MPa to 28.637 MPa.

Erratum to: Prognostics of Induction Motor Shaft Based on Feature Importance and Least Square Support Vector Machine Regression

This is an erratum to International Journal of Automotive and Mechanical Engineering 2021; 18(1): 8464–8477. Please refer to the related article: https://doi.org/10.15282/ijame.18.1.2021.06.0641

Prognostics of Induction Motor Shaft Based on Feature Importance and Least Square Support Vector Machine Regression

This paper aims to present a prognostic method for induction motor shafts that experience fatigue failure in the keyway area, using motor vibration signals. Preprocessing the data to eliminate noise in raw signals is done by decomposing the signal, using discrete wavelet transforms. Prognostic indicator candidates are obtained through the selection of features based on its importance, which involve the superposition of monotonicity and trendability parameters. The prognostics model is built based on the least squares support vector machine regression approach. Remaining useful life (RUL) estimates of motor shafts were performed by fitting the sum of two exponential functions to the regression results and extrapolating over time until the specified failure threshold hits. The results of the study show that the proposed method can work satisfactorily to estimate the RUL of motor shaft. The best prognostic indicator namely the RMS, can be used to predict the motor shaft RUL since 50% of the time step before the end of the motor shaft life is error bound within 20%.

Ensuring of the industrial robot link motion accuracy parameters in the low-speed zone

Introduction. The article is devoted to the search for a method of reducing the effect of friction links mobility industrial robot PR (production mechanism PM) with frequency-controlled electric drive (FCED) on the static error (accuracy) positioning of the working body (WB) when moving in a low speed zone. The random character of friction forces changes in the implementation process start-braking modes of induction motor (IM) operation create difficulties in performance specified technological process parameters. The formation of pulsating moments on the IM shaft, due to the stator IM current harmonics, combined with the friction torque of the moving parts in the IR (IM) guide, accompanied by a deterioration of the WB (IM output link) movement dynamics.Materials and Methods. To correction the motion of the WB (PM output link) in the IM start-brake modes, the authors proposed to use dual-mode control of the Autonomous voltage inverter (AVI), providing software control of the IM stator current harmonics amplitudes and the corresponding regulation of the pulsating moments on the IM shaft by introducing a multiple "m — submodulation" of the AVI carrier frequency (CF). Results. The simplified representation of the FCED block diagram with local and global negative feedbacks (GNF) allowed to reveal the features of specific parameters influence on the static error δ and the FCED dynamic stability with the limiting gain of the corrective amplifier K1. Discussion and Conclusions. The introduction of rotor "microvibration", allows the IM "conditionally reduce" the moving link friction force in the guides, reduce the drive power to overcome the friction forces. The use of dual-mode control AVI expands the scope of use of scalar control in process equipment, multi-link mechanisms of automated production, operating in the zone of "low and creeping speeds".

Semi-natural simulation system of a sucker-rod pump

This article describes the development of a semi-natural torque load simulation system on an induction motor shaft that simulates the operation of a sucker-rod pump (SRP). For semi-natural simulation, a laboratory bench with an induction motor (IM) and direct current motor located on the same shaft is used. The four-link mechanism kinematic scheme of a sucker-rod pump and the implementation of software modules for calculating load torque are presented. The main results of simulation tests are given.

Angular speed control of an induction motor via a solar powered boost converter-voltage source inverter combination

This paper proposes a maximum power point tracking (MPPT) algorithm for the development of a three-phase induction motor angular speed drive. A Dc-to-Dc boost power converter, powered by photovoltaic (PV) panels, feeds the three-phase power inverter. The MPPT algorithm is based on the Exact Static Error Dynamics Passive Output Feedback Controller (ESEDPOF) technique together with an Algebraic Estimator of the impedance. The estimated value is the equivalent impedance that exists between the boost converter and the three-phase inverter, and then this value is used in real-time to generate the desired reference variables of the MPPT algorithm. The angular speed-tracking controller for the induction motor is based on the well-known Field-Oriented Control (FOC) technique. An Experimental set-up was developed using an array of two PV panels. Then, a realistic scenario is carried out, and real-time results at low-speed, with and without load, are presented in order to show the effectiveness and robustness of the proposed MPPT scheme. Under this scenario, the boost converter achieves an electric power efficiency of 80%, when a nominal load torque is applied to the induction motor shaft.

Simple robust estimation of load torque in induction machines for application in real plants

The load torque information on three-phase induction motor shaft has been widely used in several researches and industrial applications, such as machinery design, optimization of control systems, incipient fault detection, among others. Torque estimation must have accurate response and affect minimally the motor drive. In this paper, a nonintrusive method for in-service torque estimation of induction motors is reported. The technique is based on the RMS value of signals, which are usually found on the machine control panel (current, voltage, and power). As a consequence, the proposed method is suitable for industrial applications. Firstly, computer simulations were performed considering motors with different power ratings in order to analyze the robustness of the proposed method. Later, experimental tests were carried for different operating conditions to validate the technique. The results were compared to those provided by a torque sensor installed on the motor shaft and to the measurements of a commercial equipment. The proposed method presented errors smaller than 2% for all points above 30% of the rated load and errors smaller than 4% below 30% of the rated load.

Effect of different methods of pulse width modulation on power losses in an induction motor

We consider the calculation of modulation power losses in a system “induction motor–inverter” for various pulse width modulation (PWM) methods of the supply voltage. Presented values of modulation power losses are the result of modeling a system “DC link - two-level three-phase voltage inverter - induction motor - load”. In this study the power losses in a system “induction motor - inverter” are computed, as well as losses caused by higher harmonics of PWM supply voltage, followed by definition of active power consumed by the DC link for a specified value mechanical power on the induction motor shaft. Mechanical power was determined by the rotation speed and the torque on the motor shaft in various quasi-sinusoidal supply voltage PWM modes. These calculations reveal the best coefficient of performance (COP) in a system of a variable frequency drive (VFD) with independent voltage inverter controlled by induction motor PWM.

Braking mode simulation of induction motor of variable-frequency drive using stator current harmonics **

The work objective is to study electrodynamic processes in the frequency-controlled drive (FCD) by the mathematical modeling method, in particular, in the two-current mode of the dynamic braking considering the 5th and 7th current harmonics of the induction motor (IM) stator. The features of forming IM stator current low frequencies (0.2-15 Hz) by the autonomous voltage inverter (AVI) followed by the additional electricity loss in the FCD, and the appearance of torque ripple on the IM shaft causing jerkiness of the actuating mechanism (AM) of the production machine (PM) executive device (ED) in the low speed zone and complicating their locating in the prearranged position, are given. It is hard to implement the FCD scheduled deceleration without trajectory correction at the friction forces ambiguity in the ED AM mobility links and availability of the torque ripple on the IM shaft. To solve this problem, the authors offer, first, to use a spatial-vector pulse-width modulation (SV PWM) with m-fold submodulation of the carrier frequency (CF) and without submodulation in the IM braking mode. Secondly, it is reasonable to apply (momentarily in a low speed area) the principle of linearization by oscillation to reduce the K friction coefficient to a decreased value in the ED AM mobility links by the IM rotor microvibration due to the 5th and 7th harmonics of the stator current. Thus, the work on modeling FCD (in Matlab + Simulink software package) allows more accurately define the impact of the 5th and 7th harmonics of the IM stator current on the capability of the software implementation of the two-current mode of the FCD dynamic braking while reducing the total energy loss in the ED AM low-speed motion area. In addition, the applicability of the proposed solutions of the electric drives of mechatronic and robotic multipurpose systems with higher requirements for positioning in the basic AM - AVI circuits is confirmed.

Sliding Mode Control For Current Loop in a Induction Motor Applied in Robot Arm

The control of a planar elbow manipulator driven by a squirrel-cage induction motor using sliding mode control (SMC) is presented in this paper. The modeling of the manipulator mechanical coupling as a load applied to the induction motor shaft is developed. This has direct influence on both dq currents, which are chosen as the sliding manifold instead of controlling both mechanical and electrical parts as individual processes like most industrial manipulators do. Conventional proportional-integral (PI) controllers are used for each loop, implying easy design procedure and implementation with low computational effort. The system can then be implemented by using a digital signal processor (DSP) and applied in industrial environments. Simulation and experimental results on a real manipulator are shown to validate the proposed control scheme. The results show that there is low steady-state error for the manipulator position.

Estimating induction motor shaft stress transients under shaft resonant and de-tuned conditions

When power to an induction motor is disconnected and then re-connected, the shaft experiences a potentially harmful transient torsional stress. The magnitude of the transient shaft stress depends on the electromagnetic torque of the motor and the resonant frequency of the system formed by the shaft and motor and load masses. To avoid resonance between transient electromagnetic torque frequencies and the mechanical natural frequency, the shaft may be de-tuned. This paper shows quantitatively the extent of worst-case resonant torques, the effect of an enforced reclosure time delay and the mitigating effects of altering the shaft resonant frequency to avoid high stresses. Peak shaft reclosure torque, when de-tuned, is independent of most motor parameters.

Effect of PWM inverters on AC motor bearing currents and shaft voltages

This paper investigates AC induction motor shaft voltage problems, current flow through motor bearings and electric discharge current problems within bearings when operated under both pure sinewave and pulse width modulated (PWM) inverter sources. Experience suggests that PWM voltage sources with steep wavefronts especially increase the magnitude of the above electrical problems, leading to motor bearing material erosion and early mechanical failure. Previous literature suggests that shaft voltage-bearing current problems under 60 Hz sinewave operation are predominantly electromagnetically induced. It is proposed that under PWM operation these same problems are now predominantly an electrostatic phenomenon. A system model to describe this phenomenon is characterized and developed. Construction and test of a new electrostatic shielded induction motor (ESIM) verifies this model and is also a possible solution to the bearing current problem under PWM operation.

Torque Sensor Using Amorphous Star-Shaped Core Magnetic Field Sensor

A method for measuring the torque exerted on an induction motor shaft by detecting differences in the shaft angles of twist is reported. A pair of precise twist angle sensors, consisting of multiple pole magnet rings surrounded by radial arrays of amorphous magnetic core field-sensitive elements, with their outputs 90° out of phase, are used to detect the angle of twisting of the shaft, from which the torque is determined. The sensor output was found to be highly linear with respect to the actual torque.

Speed Control of a Brushless Static Kramer System

A new brushless speed control system is proposed which consists of a self-cascade induction motor and a brushless commutatorless motor. The slip power extracted from the stator terminals of the induction motor is converted to mechanical power by the commutatorless motor, which is coupled mechanically to the induction motor shaft. The field control method, the advance angle control method, and the dc chopper control method for speed variation are discussed. The experiments using a prototype self-cascade motor which has single-winding schemes both on the stator and rotor show that smooth peed variation can be achieved by dc chopper control. The proposed system offers the advantages of highly reliable, maintenance-free operation, and has less reactive power and smaller harmonic contents in supply lines than conventional systems.

Integrated Manufacturing System of Electrical Machinery

It has become clear that the automation or labor saving of discrete manufacturing should be considered as the total integrated system. The concept of an integrated manufacturing system (IMS) is proposed. Cooperation among each equipment is the key to integrating the production system as the whole. System control Software plays an essential role in cooperation ired has two main functions, namely, branch and cooperation control, and schedule advance control. Compact IMS application to an induction motor-shaft machining shop has successfully been done to realize the usefulness of system control software.