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This paper aims to present an improvement to the power quality of the grid by using a colliding body optimization (CBO) based proportional-integral (PI) compensated design for a grid-connected solar photovoltaic-fed brushless DC motor (BLDC)-driven water pumping system with a bidirectional power flow control. The system with bidirectional power flow allows driving the pump at full proportions uninterruptedly irrespective of the weather conditions and feeding a grid when water pumping is not required.

Here, power quality issue is taken care of by the optimal generation of the duty cycle of the voltage source converter. The duty cycle is optimally generated by optimal selection of the gains of the current controller (i.e. PI), with the CBO technique resulting in a nearly unity power factor as well as lower total harmonic distortion (THD) of input current. In the CBO technique, the gains of the PI controller are considered as agents and collide with each other to obtain the best value. The system is simulated using MATLAB/Simulink and validated in real time with OPAL RT simulator, OP5700.

It was found that the power quality of grid using the CBO technique has improved much better than the particle swarm optimization and Zeigler–Nichols approach. The bidirectional flow of control of VSC allowed for optimum resource utilization and full capacity of water pumping whatever may be weather conditions.

Improved power quality of grid by optimally generation of the duty cycle for the proposed system. A unit vector tamplate generation technique is used for bidirectional power transfer.

Fully powered flight controls are common among many aircraft, both military and commercial. Multiple pumps are generally employed to provide these flight controls with a redundant power source in addition to many other aircraft services. The prime hydraulic source in most cases is the engine‐driven pump. It is driven directly by one of the aircraft's engines and offers the most efficient method of converting engine horsepower to hydraulic horsepower. The secondary hydraulic power source is generally not as efficient. It must derive its power from a source other than that which powers the prime pump. Present transport aircraft have utilised bleed air, ram air, electrical power, or hydraulic power to drive this redundant pump. All have demonstrated poor power‐transfer efficiency when compared to a mechanically coupled pump. This inefficiency generally results in increased cost, weight, and complexity to the aircraft. The inadequate performance of existing hydraulic power transfer units was of particular concern. This paper will address the performance problem as well as the Douglas approach to improve it.

The unpredictable failure of submersible pump (SP) in groundwater irrigation systems has considerable negative economic consequences. The purpose of this paper is to develop a total cost minimization model that aims to optimize maintenance actions for SP. It reports on simulation-based stochastic scenario analysis for evaluating total cost of maintenance.

Stochastic simulation modeling has been performed for failure of pump motor and corresponding maintenance. Five alternative scenarios were compared for total cost over 15 years starting with empirical data from a northern Ethiopian site. Downtime probabilities and spare part supply uncertainty have been considered in the mathematical model. The model is also validated using multiple ways.

The scenario comparisons indicate that despite the challenges of accessing SP doing one motor rewinding for each purchased pump system upon failure (preferably with shorter supply lead time and variability) seems to result in lowest overall costs for the time horizon considered.

The model should help to make informed practical decision regarding planning and management of SP failure systems in a developing economy context. This should, therefore, lead to better revenue for smallholder farmers and improved food security in similar context.

There are limited number of publications that consider the life cycle costs with stochastic analysis when it comes to maintenance of SPs. To the best of the authors’ knowledge, no paper has previously directly addressed maintenance cost optimization for SP in irrigation. The study could be used to develop more sophisticated stochastic models with more efficient algorithms and consideration of additional sources of stochasticity for such system.

WITH record attendances during the first days of the Motor Show this year, Exhibitors are asking if it would not be possible to have certain times, or days, reserved for trade buyers. The promoters are obviously concerned with any possible loss of gate money, but it is very true that at times, when stands are crowded with mere sight‐seers it is very difficult for genuine potential buyers and trade personnel to see what they want in the short time that may be at their disposal. These record attendances may not be repeated always; this year is the first time for a long time that anyone can order any car with a reasonable delivery date, and most cars with only a few weeks wait.

This paper reviews energy alternatives for groundwater pumping in remote, rural areas which are not grid connected or where grid extension costs are prohibitively high. The applicability of photovoltaic (PV) pumping under certain conditions is discussed, using examples of in‐service fieldwork results, and experimental results of a laboratory PV pumping rig with remote monitoring capabilities using telemetry. The outcome of the survey and analysis shows that PV pumping can be competitive with other technologies under specific head and flow conditions, although the socio‐institutional implementation strategies are crucial to the techno‐economic success of actual pumping schemes.

Retracting mechanisms may be operated either manually or by power systems, according to the type and size of aircraft. Manual systems may be classified into two main groups, mechanical and hydraulic. The mechanical group may be further sub‐divided according to the form of mechanism; e.g., cable and pulley, screw and nut, worm and other gears, all of which have been used for retraction schemes at some time or another. Power systems are even more diverse, many of them being of recent birth and, therefore, still in the experimental stage. Some of the various ways in which power can be applied to drive the retracting mechanism are by: electric motor and mechanical coupling; electric motor and hydraulic pump; aero engine coupling to hydraulic pump; compressed air motor and hydraulic pump; and other pneumatic systems.

The major steel works of the world have been the foremost industries to recognise the importance of correct lubrication. Whilst we appreciate their foresight and good sense and are particularly observant of the impetus that they have given to the subject of applied lubrication, we must not lose sight of the fact that this advancement in lubrication has been forced upon them since it is correct to state that no modern rolling mill could possibly attain anything like its present output unless the lubrication of its mill roll bearings was adequately catered for by modern lubricating equipment.

The paper aims to elaborate the method and algorithm of analysis of induction motor working in cryogenic temperature.

This paper presents the design and investigation of performance characteristics of three‐phase high voltage squirrel‐cage submerged motor. The motor is intended to work at cryogenic temperature −161°C in liquefied natural gas (LNG). The time‐stepping finite element method of transients analysis in induction motor working in cryogenic temperature has been presented. The nonlinearity of the magnetic circuit, the movement of the rotor and skewed slots have been taken into account.

The study finds that presented method and elaborated software are used to determine the steady state and dynamic performance of the high voltage squirrel‐cage submerged motor. The results of simulations and measurements of constructed model motor have been presented.

The problem has been considered as the 2D one. In order to take into account the skewed slots of the rotor the multi‐slice finite element method has been used.

Investigation presented in the paper has been performed in order to study the influence of the temperature on motor characteristics and to verify design calculations. No‐load current, starting torque and short‐circuit current during short‐circuit test, obtained on the basis of measurements and received from calculations, are in good concordance.

The paper proposes a method to determine the steady state and dynamic performance of the high voltage squirrel‐cage submerged motor working in cryogenic temperature.

CURRENTLY it is usual to demand that the entire electrical power for proposed super‐sonic airliners should be generated at a constant (400c/s) frequency. In order to do this a device called a constant speed drive (C.S.D.) is used to couple the shaft take‐off from the main propulsion engine to the electrical generator. These constant speed drives are extremely expensive items requiring specialised maintenance. On current subsonic airliners they absorb approximately 80 per cent of the time and expense required for the maintenance of the entire generating and distribution system on the aircraft. If these constant speed drives could be dispensed with a great step forward in simplification would result.

AS hydraulic systems in modern military and commercial aircraft continue to grow in size and complexity with practically each new aircraft introduced, many aircraft manufacturers are turning to the use of power transfer units to help hold down overall hydraulic system weight and complexity. A power transfer unit allows transfer of hydraulic power from one system to another without transfer of hydraulic fluid (Fig 1).