Curve Of Motor Research Articles

Probing for the Energy-Conserving Load Rates of the Asynchronous Motor by Harnessing the Efficiency and Power Factor Synergy

In the light of the energy saving drive and environmental concerns in today’s world, the technical and procurement staff of industries are encouraged to invariably take into consideration, motor efficiency as well as power factor in their motor load analyses prior to embarking on motor installation/replacement decisions. It is believed that with this practice, which hinges on a tradeoff between loading at high operating power factor and loading at high operating efficiency, the motor-driven business may stand a better chance of being run greener and more economical. This article proposes a method that engineers in research or in charge of the operations and maintenance of the 3-phase squirrel cage induction motor (SCIM) in business, may deploy to arrive at the energy efficient load range/rates for the machines of interest. The method was developed with the aid of the following motor curves viz: the load/efficiency curve, the load/compensated power factor curve as well as the load/kilovolt ampere reactive (KVAR) curve; and demonstrated on three different SCIM ratings, to determine their respective most energy efficient bounds of loading. Field data, z-score analysis and the power loss simulations were used for validating the proposed method. The energy efficient load range/rate was found to be machine-specific and the width of this load range seemed to be jointly governed by the high efficiency span of the load-efficiency curve as well as the load-wide profile of the power factor over the most part of the SCIM loading, up to full load. The mean optimal loading for the machines investigated, ranged from 66% - 73%, with standard deviations not exceeding 15.85%.

An interference-adjusted power learning curve for tasks with cognitive and motor elements

Production and operations management (POM) uses learning curve (LC) models to determine the length of training sessions for new workers and predicting future task performance. Empirically validated LC parameters provide managers with quantitative information on the effects of the presumed factors behind the learning process. Previous studies considered LC to compose of cognitive and motor curves. Another widely acknowledged but only recently parameterized phenomenon in the POM field is interference, which assumes some loss of information or experience could occur over a learning session. This paper takes a logical step in this line of research by developing an interference-adjusted power LC model, a composite of cognitive and motor elements. This paper accounts for the decay of cognitive and motor memory traces from repetitions to measure the residual (interference-adjusted) experience and capture these phenomena. Three variants of the model are developed that assume power and exponential decay functions and an approximate version of the exponential one. Assembly data representing various forms of an individual learning profile have been used to test the fits of the developed models. In addition to those models, four potential models from the literature were selected for comparison purposes. The results show that the approximate model fits very well exponential learning profile. The findings highlight the confluence of the three phenomena in learning, component (cognitive/motor) learning, interference, and plateauing.

Development curves of motor and daily activity performance of individuals with cerebral palsy from childhood into adulthood

Development curves of motor and daily activity performance of individuals with cerebral palsy from childhood into adulthood

Study of regenerative breaking control for HEV with multispeed transmission

This study describes method of regenerative breaking control for HEV with multispeed transmission. When a gear is shifted during regenerative breaking, almost all TMED HEVs in the world lose decelerate linearity or reduce regenerative breaking to get decelerate linearity. So fuel efficiency is get down. We made concept that is called regenerative breaking practical quantity. Regenerative breaking practical quantity solved problem of decelerate linearity. And this technology is used in all TMED HEVs of Hyundai motor group. Regenerative breaking practical quantity reflect a characteristic curves of motor, shifting process of multispeed transmission and following of hydraulic brake for cooperative control of HCU, MCU, TCU, AHB and so on. As a result of this technology, decelerate linearity is retained for sale the HEV. Furthermore fuel efficiency is improved about 8.4% because regenerative breaking quantity is increased about 28%.

The Optimal Design of Fuel Cell Bus Power Train

The transmission ratio of the fuel cell city bus should meet the requirement of economy and power performance. The transmission ratio and the main decelerator are the key factors to the economy and power performance of the bus. The special operating characteristic curve of motor is a basis to analyze the vehicle`s power and economy performance. Combined with the planned and the provided transmission ratio, the optimal gear ratio of the transmission can be calculated. So the vehicle`s economy and power performance are finally improved.

Impact of windings switching on torque‐speed curves of PM BLDC motor

PurposeWhen phase windings of brushless DC motor are switched, additional voltage drops across inductances of main circuit appear. These drops lead to, among other effects, increase of torque‐speed curve slope. The discussed research has been aimed at working out a simple and precise method of identifying torque‐speed characteristic of PM BLDC motor. The elaborated method takes into account the influence of windings switching and motor inductances on motor torque‐speed characteristic. In order to assess the results, extensive test simulations of models implemented in Matlab/Simulink software have been run. Results of analysis and test simulations have been compared with lab test results of two real PM BLDC motors.Design/methodology/approachAnalytical calculations take into consideration phenomena occurring during windings switch‐overs and impact of inductance on emerging voltage and rotational speed drops. It has been pointed out that on account of main circuit inductance, the average value of source current is less than average value of equivalent current generating electromagnetic torque. For analysis sake it has been assumed when windings are being switched‐over the current is kept constant; the motor parameters have also been assumed to be constant.FindingsA novel and accurate method of determining torque‐speed characteristics of PM BLDC motor has been worked out. This method has been investigated with the help of motor computer models implemented in Matlab/Simulink software and the obtained results have been subsequently compared with results of laboratory tests of two commercially available PM BLDC motors.Research limitations/implicationsThe object of the research was brushless DC motor with permanent magnet excitation. The impact of windings switch‐overs on torque‐speed curves of the motor has been analysed. Analytical method which makes it possible to determine torque‐speed curve of this motor very easily has been elaborated. Computer model of PM BLDC motor for Matlab/Simulink software has also been worked out. Extensive simulations helping to verify the proposed method have been run. Results of analysis and simulation tests have been verified by means of laboratory tests of two commercially available PM BLDC motors.Practical implicationsPM BLDC motors are used more and more widely. The new method of determining PM BLDC motors torque‐speed curves will facilitate analysis and design of drive systems utilizing these motors and will also speed up calculations.Originality/valueThe presented method of determining torque‐speed curves of PM BLDC motor is novel and much more precise than methods commonly used nowadays. Recognized methods usually neglect impact of inductance on motor properties.

Extending the Range of In Vivo Multimotor Force-Velocity Curves by Sizing Vesicles Below the Diffraction Limit

In our previous work (Shtridelman et al. 2008, Cell Bioch. & Biophys), we presented three force-velocity curves corresponding to 1, 2, and 3 motors/vesicle. We constructed these curves via velocities obtained directly from vesicles (NT2 cells, 37°C) and via forces obtained indirectly from Stokes' Law using measured intracellular viscosity, and vesicle diameters and velocities as inputs. The range of these earlier curves was restricted by the diffraction limit. In our current work, we use the image intensity--obtained with a differential interference contrast (DIC) microscope--as a proxy for vesicle diameters smaller than the diffraction limit. This novel sizing method is surprisingly robust, allowing us to extend the range of our in vivo multimotor force velocity curves. As with our previous curves, our newly extended 1-motor in vivo curve is similar to in vitro single kinesin force-velocity curves obtained at 35°C and, qualitatively, to single dynein curves obtained at 25°C. However, the 2- and 3- motor curves have proportionally higher extrapolated stall forces and overall velocities. The figure accompanying this abstract shows the primary size-velocity data we used to generate our extended in vivo multimotor force-velocity curves.View Large Image | View Hi-Res Image | Download PowerPoint Slide

A-C Motor Protection

An investigation of motor protection can be made by a comparison of the proper motor and thermal overload relay data. Convenient data for this are motor ``protection'' curves for comparison with ``tripping time'' curves of thermal overload relays. These motor curves should include single phase operation of polyphase motors as this is one of the abnormal conditions for which motors should be protected. The capacity of the motor at different expected ambient temperatures should be compared with the capacity of the overload relay at its corresponding ambient temperatures.

A-C motor protection

An investigation of motor protection can be made by a comparison of the proper motor and thermal overload relay data. Convenient data for this are motor “protection” curves for comparison with “tripping time” curves of thermal overload relays. These motor curves should include single phase operation of polyphase motors as this is one of the abnormal conditions for which motors should be protected. The capacity of the motor at different expected ambient temperatures should be compared with the capacity of the overload relay at its corresponding ambient temperatures.

A Recording Torque Indicator That Records the Torsional Effort of Motors During Acceleration

The measurement of torque under unstable conditions of speed is usually extremely difficult and inaccurate when a dynamometer, prony brake, or similar torque measuring equipment is used. The device described in this paper was developed primarily to obtain torque measurements under unstable conditions as well as under stable conditions, and to obtain a permanent record of these measurements. It has been particularly successful in recording speed-torque curves of motors during acceleration and it can also be applied very effectively to other fields.