scholarly journals Study of the influence of different designs of massive rotor of asynchronous generator on their maximum power

2020 ◽  
Vol 216 ◽  
pp. 01177
Author(s):  
Yu. Bobozhonov ◽  
B. Seytmuratov ◽  
B. Fayzullaev ◽  
A Sultonov

The article deals with the experimental results of the short-circuit experience, active and inductive resistances of a massive rotor with short-circuited copper cells. And also experimental mechanical characteristics of model asynchronous generators with different massive rotors at the same overall power have been studied.

Author(s):  
Koji Kondo ◽  
Koji Sato ◽  
Satomi Takahashi ◽  
Toshiyuki Sawa

Bolted pipe flange connections with metallic gaskets have been used under higher pressure as well as higher temperature. However, a few researches on the mechanical characteristics in connections with metallic gaskets have been carried out. It is necessary to examine the mechanical characteristics such as the contact gasket stress distributions which govern the sealing performance, the deformation of the metallic gaskets, changes in axial bolt forces and the hub stress under higher pressure and temperature. In the present paper, the objectives are to examine the changes in axial bolt forces, the hub stress and the contact gasket stress distributions and the sealing performance of the pipe flange connections with metallic flat gaskets. Firstly, the mechanical characteristics of the connections under higher pressure are analyzed using FEA. Then, experiments were carried out to measure the load factor, the hub stress and the leak rate (the sealing performance). The relationship between the average contact gasket stress and the leak rate was measured using platen device at room temperature. The FEA results are fairly coincided with the experimental results. It is shown that the leak rate decreases as the contact gasket stress increases and when the plastic deformation of gaskets occurs, the sealing performance increases. The leak rate was measured in the range of 10−4∼10−7 [Pa·m3/s]. It is found that the sealing performance increases as the gasket width increase in the elastic deformation range while it is independent of the gasket width when the plastic deformation occurs. The effect of temperature on the mechanical characteristics of the connection is also examined. The FEA results are in a fairly good agreement with the experimental results. It is found that the sealing performance increases as the temperature increases. In addition, a method how to determine the bolt preload for increasing the sealing performance is proposed.


2008 ◽  
Vol 62 (3) ◽  
pp. 160-163 ◽  
Author(s):  
Aleksandra Mitovski ◽  
Ljubisa Balanovic ◽  
Dragana Zivkovic ◽  
Sasa Marjanovic ◽  
Bata Marjanovic ◽  
...  

The results of structural and mechanical characteristics of lead-free Cu-Sn based solder alloys, produced in Company "11. mart" AD Srebrenica (Republic of Srpska), are presented in this paper. The results of investigation of samples - alloys CuSnl4, CuSnlFelAlO.5, CuSnlOFelAllMnO.5 and CuA110Fe3Mn produced by different processing methods, include the data obtained by optical microscopy and measurements of hardness, micro hardness and electroconductivity, in order to characterize mentioned alloys and define the influence of processing method applied on their structural and mechanical properties. Microstructural experimental results of samples produced by casting in a metal mould with fast water cooling showed clearly sharp dendritic structure. Samples obtained by casting in a sand mould, displayed structure with big crystals, higher amount of segregation and inclusions on the grain boundaries, as a result of the slow cooling process. Hardness and microhardness tests showed increasing values as the amount of tin raised. Sample 3 showed the lowest value, as a result of the crystallization process and lackness of additional thermal treatment. Experimental results of the electroconductivity test showed that mentioned sample has got the highest value, which can be also explained by its production method. Results presented in this paper can contribute to investigations of copper-tin lead-free alloys, having in mind that various potential lead-free solders still haven't been completely investigated from the aspects of their structural, mechanical and electrical properties.


Author(s):  
Mohammed Salah Bouakkaz ◽  
◽  
Ahcene Boukadoum ◽  
Omar Boudebbouz ◽  
Issam Attoui ◽  
...  

In this work, a survey is carried out on six MPPT algorithms which include conventional and artificial intelligence based approaches. Maximum Power Point Tracking (MPPT) algorithms are used in PV systems to extract the maximum power in varying climatic conditions. The following most popular MPPT techniques are being reviewed and studied: Hill Climbing (HC), Perturb and Observe (P&O), Incremental Conductance (INC), Open-Circuit Voltage (OCV), Short Circuit Current (SCC), and Fuzzy Logic Control (FLC). The algorithms are evaluated, analyzed, and interpreted using a Matlab-Simulink environment to show the performance and limitations of each algorithm


2016 ◽  
Vol 3 (1) ◽  
pp. 9-14 ◽  
Author(s):  
R. Ahiska ◽  
L. Nykyruy ◽  
G. Omer ◽  
G. Mateik

In this study, load characteristics of thermoelectric and photovoltaic solar panels areinvestigated and compared with each other with experiments. Thermoelectric solar panels convertsthe heat generated by sun directly to electricity; while, photovoltaic solar pales converts photonicenergy from sun to electricity. In both types, maximum power can be obtained when the loadresistance is equal to internal resistance. According to experimental results, power generated fromunit surface with thermoelectric panel is 30 times greater than the power generated by photovoltaicpanel. From a panel surface of 1 m2, thermoelectric solar panel has generated 4 kW electric power,while from the same surface, photovoltaic panel has generated 132 W only.


Author(s):  
Elhem Ghorbel ◽  
Mariem Limaiem

This research investigates the efficiency of using Flax Fibers reinforced bio-sourced polymer by comparison to traditional system based on Carbone Fiber Reinforced Epoxy Polymer in order to confine recycled aggregates concrete. Four concrete formulations have been formulated by incorporating recycled aggregates from demolition waste (0%, 30%, 50% and 100%). An air-entraining agent was added to the formulations to achieve the level of 4% occluded air. The main objective is to discuss and to evaluate the effectiveness of confining them using bio-sourced composite by comparison to traditional ones. To hit this target, the developed approaches are both experimental and analytical. The first part is experimental and aimed to characterize the mechanical behavior of the materials: the composites used in the confining process the unconfined concrete (effect of incorporating recycled aggregates on the overall mechanical characteristics). We establish that bio-sourced composites are efficient in strengthening recycled aggregates concrete especially if they are air-entrained. The second part of this work is dedicated to analytical modeling of mechanical behavior of confined concrete with composite under compression based on Mander’s model. The input parameters of the model were modified to consider the rate of recycled aggregates incorporation. Comparison between experimental results and the modified Mandel’s Model is satisfactory.


2016 ◽  
Vol 12 (2) ◽  
pp. 123-136 ◽  
Author(s):  
Ammar Aldair ◽  
Adel Obed ◽  
Ali Halihal

Nowadays, renewable energy is being used increasingly because of the global warming and destruction of the environment. Therefore, the studies are concentrating on gain of maximum power from this energy such as the solar energy. A sun tracker is device which rotates a photovoltaic (PV) panel to the sun to get the maximum power. Disturbances which are originated by passing the clouds are one of great challenges in design of the controller in addition to the losses power due to energy consumption in the motors and lifetime limitation of the sun tracker. In this paper, the neuro-fuzzy controller has been designed and implemented using Field Programmable Gate Array (FPGA) board for dual axis sun tracker based on optical sensors to orient the PV panel by two linear actuators. The experimental results reveal that proposed controller is more robust than fuzzy logic controller and proportional-integral (PI) controller since it has been trained offline using Matlab tool box to overcome those disturbances. The proposed controller can track the sun trajectory effectively, where the experimental results reveal that dual axis sun tracker power can collect 50.6% more daily power than fixed angle panel. Whilst one axis sun tracker power can collect 39.4 % more daily power than fixed angle panel. Hence, dual axis sun tracker can collect 8 % more daily power than one axis sun tracker.


1979 ◽  
Vol 101 (2) ◽  
pp. 135-138
Author(s):  
Amit Bagchi ◽  
John G. Lenard

Two mathematical models proposed by Avitzur and valid for axially symmetrical square extrusion are tested for their ability to predict the maximum power required in single as well as multiple hole extrusion. Comparison to experimental results obtained using plumber’s lead shows good correlation. The most significant parameter is shown to be the total area reduction. The velocity field in multiple hole extrusion—which by necessity must be nonaxially symmetrical—appears not to affect the power required for extrusion.


Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 794 ◽  
Author(s):  
Huang ◽  
Hu ◽  
Han ◽  
Lei ◽  
Yang

One of the reasons why commercial application of surface acoustic wave (SAW) atomization is not possible is due to the condensation of aerosol droplets generated during atomization, which drip on the interdigitated transducer (IDT), thereby causing electrodes to short-circuit. In order to solve this problem, a SU-8-2002 film coating on an IDT is proposed in this paper. The waterproof performance of the film coating was tested on a surface acoustic wave (SAW) device several times. The experimental results reveal that the film coating was robust. The experiment also investigated the effects of the SU-8-2002 film on atomization behavior and heating.


Author(s):  
Hiroshi Nagayoshi

Basic characteristics and dynamic response of a 30W module/array simulator using PV I-V magnifier circuit was studied. It was confirmed that each gain of voltage and current was independently adjustable using feedback control of current signal. Simulator circuit output power is controlled by LED irradiation light which works as an irradiation of sun light to real PV modules. Maximum power of the circuit depends on maximum power of the power amplifier used in the circuit. A photo-current of pn photo-sensor was some micro ampere hence the current gain of the simulator needed more than 50dB. The voltage gain was not more than 3dB because a multi junction pn photo-sensor was used. To control the simulator circuit by personal computer, an LED driver circuit was added. A fill factor was also easily changeable by change of shunt resistor connected with pn photo-sensor in parallel. A dynamic response of short circuit current was measured and confirmed that the circuit has enough response ability to apply the MPPT evaluation. A grand line of each module is isolated, hence any topology of connections is available. This circuit simplifies the control system and makes it easy to handle multi simulator units by one personal computer. This system is suitable for the evaluation of multi inverter system.


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