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1

The accuracy of defining the energy efficiency of drive systems exemplified by comparison with hydrostatic drives with proportional motor speed control

Skorek Grzegorz

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2019

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nr 58 (130)

32--41

EN

The aim of the article is to look at the possibility of accurately determining the energy efficiency of drive systems. The results of experimentally determined efficiencies and the efficiencies determined from simulations of two hydrostatic systems with throttling control and fed by a constant capacity pump were compared. The research apparatus was very precisely designed, made and automated. The measuring instruments that were used are characterized by their high measuring accuracy. The issues related to the determination of the energy losses and the energy efficiency of the hydraulic motor or drive system, which should be determined as dependent on the physical quantities independent of these losses, were also discussed. A Paszota diagram of the power increase in the direction opposite to the direction of the power flow, replacing the Sankey diagram of the power decrease in the direction of the power flow in the hydraulic motor or in the drive system, was analyzed. The results showed that a Paszota diagram opens up a new perspective on research on the power of energy losses and energy efficiency of hydraulic motors and drive systems.

2

Energy saving systems of hydrostatic drives for ship deck machines

Skorek G.

New Trends in Production Engineering

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2018

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Vol. 1, Iss. 1

507--514

EN

A control system with a proportional directional throttling control valve or a directional control servo valve, controlling a cylinder (linear hydraulic motor) is used in the ship steering gear drive, in the controllable pitch propeller control, in the variable capacity pump control system for hydraulic deck equipment motors or fixed pitch propellers in small ships (for example ferries). Energy savings in a constant capacity pump operation can be achieved by means of overflow valve controlled by the oil outlet pressure between the directional throttling control valve and the cylinder. Although structural volumetric losses cannot be eliminated in such a system, but it is possible to reduce considerably structural pressure losses, mechanical losses and volumetric losses in the pump, and mechanical losses in the cylinder too. The paper discusses these energy savings using an earlier developed by Paszota mathematical model of losses in elements, the energy efficiency of the system and the operating range of the cylinder. The paper also presents a comparison of the energy behavior of two widespread structures of hydrostatic systems: a standard individual systems with a throttling steering fed by a constant capacity pump. Both system solutions are described and equations of the total efficiency η of the system are presented. Diagrams of energy efficiency of two hydraulic systems working at the same parameters of a speed and a load of hydraulic linear motor, which were different due to structure and ability of energy saving, were presented and compared.

3

Selekcjonowanie mocy strat blach transformatorowych w obwodach magnetycznych zamkniętych i otwartych

Żurek Z. H., Solecka B., Wolnik P., Chmiela B.

Napędy i Sterowanie

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2018

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R. 20, nr 5

90--96

PL

Moc strat jest podstawowym parametrem przy projektowaniu maszyn i urządzeń elektrycznych. W przemyśle spotyka się blachy różnych producentów z różnych serii, dlatego zachodzi konieczność wstępnego szybkiego ich selekcjonowania pod względem mocy strat całkowitych. Oprócz metod Epsteina, międzynarodowe normy dopuszczają pomiary na pojedynczych arkuszach czy pasmach w metodach Single Sheet Testing (SST) dla grain-oriented Fe-Si sheet steel. W artykule porównano realizacje zastosowań koncepcji fizycznych i zastosowań NDT selekcjonowania stratności całkowitej blach transformatorowych z pomiaru składowych impedancji na pojedynczych próbkach paskowych otwartych i pojedynczych arkuszach blach. Do badań użyto arkuszy blach transformatorowych M130 z różnych serii poprodukcyjnych. Pomiary parametrów arkuszy blach transformatorowych wykonano na urządzeniu pomiarowym BROCKHAUS STS zgodnie z normami IEC 6040. Mostkiem pomiarowym AGILENT 4294A wyznaczano składowe impedancji cewki pomiarowej PCB (Texas Instrument) przylegającej do arkusza blachy. Niezależnie badano paski blachy transformatorowej (próbki otwarte) w solenoidzie. Pomiary wykonano w zakresie częstotliwości do 4 MHz. Pomiar w zakresie częstotliwości rezonansowej miał na celu ocenę użyteczności sondy pomiarowej LDC (TI) z cewką spiralną PCB.

EN

Power loss is the basic parameter important for designers, in the construction of electrical machines and equipment. There are different magnetic steel sheets by various designers with various production series produced by industry. Therefore, it is necessary to pre-fast select them according to their total power loss. In this case, several methods are allowed by international standards, besides the Epstein apparatus (i. e. Single Sheet Tester (SST) for grain-oriented Fe-Si sheet steel). In the present paper, the comparison between the implementation of the physical concept and NDT applications and selection of total power loss of transformer shits was discussed. Investigations were carried out for single open strip samples and single transformer sheets by measured complex impedance components. M 130 type transformer sheets from different post-production series were used. The measurements of these sheets were carried out by applying BROKHAUS STS system according to the IEC 6040 standard. The complex components of impedance for a measure coil PCB (Texas Instrument), adhering to the sheet, were also measured by applying the precision RLC meter (AGILENT 4294A). Independently, the open strip samples were measured in a solenoid coil for the frequency up to 4 MHz. The resonant frequency measurements were carried out in order to test the LDC (TI) probe with a spiral measuring coil PCB.

4

Influence the applied control structure on energy efficiency of the hydrostatic system

Skorek G.

Journal of KONES

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2018

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Vol. 25, No. 3

411--418

EN

A control system with a proportional directional throttling control valve or a directional control servo valve, controlling a cylinder (linear hydraulic motor) is used in the ship steering gear drive, in the controllable pitch propeller control, in the variable capacity pump control system for hydraulic deck equipment motors or fixed pitch propellers in small ships (for example ferries). The hydraulic system is designed first of all taking into consideration the nominal parameters of the cylinder load and speed. For such parameters, the energy efficiency of the elements and complete system is described. Meanwhile the exploitation conditions can vary in full range changes of the cylinder load and speed coefficients. The article presents a comparison of the energy behaviour of two widespread structures of hydrostatic systems: a standard individual systems with a throttling steering fed by a constant capacity pump. Both hydraulic solutions are described and equations of the total efficiency η of the system are presented. Diagrams of energy efficiency of two hydraulic systems working at the same parameters of a speed and a load of hydraulic linear motor, which were different due to structure are presented and compared, as well ability of energy saving. This publication also presents analyses and compares the areas of the power fields of energy losses occurring in the elements of two hydraulic systems with different structures of the hydraulic linear motor speed control.

5

Comparison of the structural and total energy efficiency of selected hydraulic systems with proportional control linear motor

Skorek G.

Journal of KONES

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2016

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Vol. 23, No. 2

317--324

EN

In the paper are presented the diagrams of the structural energy efficiency of system with the throttling control assembly and total energy efficiency of the system with constant or variable capacity pump cooperating an overflow valve with the throttling control of the linear hydraulic motor. Diagrams of total energy efficiency of three hydraulic systems working at the same parameters of speed and load of hydraulic linear motor, which were different due to structure and ability of energy saving were presented and compared. This publication also presents analyses and compares the areas of the power fields of energy losses occurring in the elements of three compared hydraulic systems with different structures of the hydraulic linear motor speed control on example on Load Sensing system. The graphical interpretation of the power of losses in the hydrostatic drive and control system elements lets to compare the same power fields of energy losses with other power fields of another structure. This enables to understand what energy losses are the biggest and in which elements of compared hydraulic systems. The best possibility to use in system, as a supply source of the hydraulic cylinder speed series throttling control assembly, is a set consisting of a variable capacity pump cooperating with a Load Sensing (LS) regulator, which totally eliminates the structural volumetric losses in a system. Power ΔPstv of structural volumetric losses is equal to zero, because the current pump capacity QP is adjusted, by the LS regulator, to the current flow intensity QM set by the throttling assembly.

6

The opportunities for getting energy savings in the hydrostatic drive system

Skorek G.

Journal of KONES

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2014

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Vol. 21, No. 2

273--280

EN

Full picture of the energy losses in a hydrostatic drive system is a picture of the power of energy losses in the system elements. Paper presents the areas of the power fields of energy losses occurring in the elements of some hydraulic systems with different structures of the hydraulic motor speed control. Proposed graphical interpretation allows analysing and comparing different hydrostatic drive systems. In many constructed and manufactured machines currently used hydrostatic drive systems or electro hydrostatic systems of varying complexity. Today, the need for energy-efficient systems forces to some extent the development and improvement of computational methods using computer aided relating to energy efficiency systems. Hydrostatic systems especially in modern machines play a very important role. Actuators, such as hydraulic motors, hydraulic cylinders is commonly used for a long time, including on machines and equipment land and marine. Unawareness of proportions of the energy, volumetric, pressure and mechanical losses in elements is often the case. Problems connected with energy efficiency are essential for improvement of functionality and quality of hydrostatic drive systems, characterised by unquestioned advantages. Energy efficiency of hydrostatic transmissions, particularly those with throttling control of the motor speed, and also efficiency of the hydraulic servomechanism systems may be in fact higher than the values most often quoted in publications on the subject.