Power Consumption Simulation of Servo Motors Focusing on the Influence of Mechanical Vibration on Motor Efficiency

This paper presents a simulation method for the power consumption of servo motors, focusing on the influence of vibrations on the motor efficiency. An apparatus consisting of two servo motors connected through a coupling was specifically designed for this study. The efficiency of the servo motor was experimentally investigated for several torque vibration levels imposed through the selection of the control parameters, and the torque vibration level was quantified through the standard deviation of the torque signal. The efficiency map characteristics for each torque oscillating level were determined. A numerical model of the apparatus clarifying the dependency of the coupling characteristics on the oscillating torque was developed, and the torque oscillation of the system was simulated. A model based on the measured motor efficiency maps and the torque oscillation level was developed to simulate the motor efficiency under several torque vibrating conditions. Finally, the power consumption of the motor was simulated based on the simulated efficiency and mechanical power. A balance of input, output, and loss powers was presented, and the experimental measurements were compared with the simulation results. The power consumption of the motor increased when the torque oscillated owing to vibrations, and the loss of power due to both oscillations and the loss of motor efficiency was quantified.

Analysis of Vibration and Noise on Vibrating Screen at PT. Mifa Bersaudara

The purpose of this study was to analyze the level of vibration and noise on the Equipment Vibrating screen crusher FC 02 at PT. MIFA Bersaudara. Vibration is measured using a vibration meter, noise is measured by a digital sound level meter. Measurements are made on the x, y and z axes at each measurement point. The results showed that the value of the vibration level on the Vibrating screen crusher FC 02 on the x-axis with the velocity value of 28.56 mm/s, the y-axis value of 29.82 mm/s and the z-axis velocity value of 25.46 mm/s. While the Acceleration value on the x-axis is 20.7 m/s 2 the value is 30.86 m/s 2on the y and z axes of 21.42 m/s 2 . While the noise value indicates that the average value on the right side is 99.6 dBA on the right side and 101.7 dBA on the left side. Efforts were made to overcome the problem, namely by not operating the VSC FC 02 exceeding the recommended maximum limit of 60 dBA and the maximum allowed which is 70 dBA so as to prevent problems of comfort, health, and safety at work. Operators and employees are advised to stay at the location for no more than 15-30 minutes, if more than that time must use safety earmuffs.

Modifikasi Mesin Pencacah Plastik PET Tipe Gunting dengan Kapasitas 50 kg/jam

Abstrak Mesin pencacah plastik merupakan sebuah mesin yang dirancang untuk mencacah sampah plastik agar mengurangi volume sampah. Mesin pencacah dirancang mampu mencacah sampah dengan kapasitas pencacahan 50 kg/jam, hasil analisa kinerja mesin pencacah memperlihatkan bahwa kapasitas mesin pencacah adalah 36.68 kg. Analisis kinerja mesin lain adalah: efisiensi mesin nilainya 73,37 %; tingkat kebisingan mencapai 80,6 dB; getaran yang dihasilkan saat melakukan pencacahan adalah 4,9 mm/s2, dan rendemen cacahan 73,45 %. Hasil analisa kinerja memperlihatkan bawah mesin pencacah perlu dimodifikasi agar sesuai dengan hasil perancangan awal. Modifikasi dilakukan dengan mengubah saringan, mengatur ulang jarak antara mata pisau, dan menambahkan pisau pada pisau putar. Modifikasi yang dilakukan berhasil meningkatkan kapasitas mesin pencacah menjadi 42,59 kg/jam; tingkat kebisingan menjadi 76,8 dB; tingkat getaran mesin 3,84 mm/s2; dan kualitas hasil cacahan menjadi baik yaitu plastik terpotong. Kata kunci: modifikasi, kinerja, sampah, daur ulang, mata pisau Abstract The plastic chopping machine is a machine designed to chop plastic waste in order to reduce the volume of waste. The chopping machine is designed to be able to chop waste with a chopping capacity of 50 kg / hour, the results of the chopping machine performance analysis show that the chopping machine capacity is 36.68 kg. Other engine performance analyzes are: the engine efficiency is 73.37%; noise level reaches 80.6 dB; The vibration generated during the counting was 4.9 mm / s2, and the chopping yield was 73.45%. The results of the performance analysis show that the chopping machine needs to be modified to match the results of the initial design. Modifications were made by changing the filter, resetting the distance between the blades, and adding blades to the rotary knife. The modifications made were successful in increasing the capacity of the chopping machine to 42.59 kg / hour; noise level to 76.8 dB; machine vibration level 3.84 mm / s2; and the quality of the chopped results is good, namely the plastic is cut. Key words: modification, performance, waste, recycling, blade

Study on Vibration Damping Mechanism of Shoe Sole with Alternating Lattice Structure Using Vibration Level Difference

As one of the media of the ground and feet, the design of footwear products has lately received great attention, and the cushioning performance of the sole has become a key factor for the comfort and sportiness of the foot. In this paper, a new type of middle sole sports shoes with an alternating gradient lattice structure was proposed. The dynamic response of the structure was analyzed by ABAQUS software, and the model was validated by modal analysis. The effects of different kinds of alternating lattice and uniform lattice sole models on vibration isolation were analyzed by using the vibration level difference as the evaluation index of vibration characteristics. The analysis results are as follows: (a) We found that the mean of the vibration level difference of the alternating gradient structure is higher than that of the uniform lattice structure, which confirms the feasibility of the alternating gradient arrangement and its excellent buffering performance. (b) Two kinds of vibration stage drop values of the 24-series alternating lattice structure model are analyzed, and “C-G-X″ structure has the highest vibration stage drop value. In addition, the comprehensive analysis of the alternating gradient lattice structure of the soles shows that the four types of structures have good cushioning performance, and the C-series structure in the frequency range of 0–140 Hz vibration level difference value is higher than other series. The results show that the evaluation index of vibration level difference based on mechanical vibration characteristics can accurately analyze the response of different structure soles to vibration, which also provides a method for the future design of vibration reduction and exploration of the biomechanics of footwear.

Hydraulic Turbine Performance Assessment with Implementation of an Innovative Aeration System

The environmentally friendly concept in terms of water quality represents a condition for developing hydropower plants all around the world. Since 2017, hydropower has represented more than 70% of all renewable energy production and it is essential for the integration of the other renewable sources of energy and for regulation of the grid. To maintain the “green” label concerning the dissolved oxygen level (6 mg DO/L), the energy suppliers should respond to environmental concerns about the operation of hydropower plants. In the context of sustainable development, the ecological degradation of rivers is unacceptable due to the implementation of a hydropower plant on the watercourse. For deep reservoirs or tropical regions, the oxygen level in the water downstream of the hydropower plants may be low and affect the aquatic life for many kilometers downstream. This paper presents a new aeration system for discharged water from hydropower plants that provides water aeration with minimum energy consumption. The influence of the aeration process on the turbine operation and efficiency is analyzed. Experimental measurements are carried out on site on a small Francis turbine. The influence of the aeration process on the turbine mechanical performances (vibration level and relative displacement) and hydraulic performances (turbine efficiency, power output, and pressure fluctuation) is analyzed. The results showed that the impact of the aeration device implementation and operation over the energetic characteristics of the turbine is in the efficiency measurements accuracy range. The aeration through this device did not influence the turbine operation (vibration, level, or pressure fluctuations).

Load noise prediction of a power transformer

In this article, we propose a new regression equation to predict the noise of a power transformer based on the winding vibration under a loading condition. A regression between load noises and tank vibrations for multiple transformers with different rated powers was confirmed through measurements and regression analysis. A regression equation for load noise and winding vibration was derived considering the fact that the winding vibration level is proportional to the tank vibration level. The electromagnetic force, which is the excitation force of the winding, was obtained using the equivalent magnetic circuit network method to obtain the winding vibration required for the regression equation. Subsequently, the obtained force was applied to a finite element model for the winding to achieve the vibration response. The winding vibration obtained through these methods is closely correlated with the load noise, and the amount of winding vibration transferred to the tank could be changed according to the distance between the tank and the winding. Accordingly, an equation for predicting the load noise was established considering the winding vibration and the correlation factors according to the distance of the transmission path. The proposed prediction equation is considerably more accurate than the previous prediction equation.

A Method of Predicting The Best Conditions for Clamping a Large-Size Workpiece in Order To Reduce Vibrations in The Milling Process

The paper presents an innovative method of solving the problem of vibration suppression during milling of large-size details. It consists in searching for the best conditions for clamping the workpiece based on a rapid modal identification of the dominant natural frequencies only and requires repetitive changes in the tightening torque of the clamping screws. Then, by estimating the minimum work of the cutting forces acting in the direction of the width of the cutting layer, it is possible to predict the best fixing of the workpiece. Application of the method does not require the creation and identification of a computational model of the process or preliminary numerical simulations. The effectiveness of this method was confirmed by the evaluation of the Root Mean Square (RMS) of the vibration level in the time domain observed during the actual face milling process.

Numerical Investigation of the Trailing Edge Shape on the Added Damping of a Kaplan Turbine Runner

Hydraulic turbine runners experience high excitation forces in their daily operations, and these excitations may cause resonances to runners, which may induce high vibrations and shorten the runner's lifetimes. Increasing the added damping of runners in water can be helpful to reduce the vibration level during resonances. Some studies have shown that the modification of the trailing edge shape can be helpful to increase added damping of hydrofoils in water. However, the influence of blade trailing edge shape on the added damping of hydraulic turbine runners has been studied in a limited way before. Due to the difficulties to study this problem experimentally, the influence of blade trailing edge shape on a Kaplan turbine runner has been studied numerically in this paper and the one-way FSI method was implemented. The performances of three different turbulence models, including the k − ϵ , k − ω SST , and transition SST models, in the added damping simulation of the NACA 0009 hydrofoil were evaluated by comparing with the available results of the two-way FSI simulation in the references. Results show that, unlike the significantly different performances in the two-way FSI method, the performances of all the turbulence models are very close in the one-way FSI method. Then, the k − ϵ turbulence model was applied to the added damping simulation of a Kaplan turbine runner, and results show that the modification of the blade trailing edge shape can be helpful to increase the added damping to some extent.