The high-speed induction motor: calculating the effects of solid-rotor material on machine characteristics

A method for the analysis of high-speed solid-rotor induction motors in presented. The analysis is based on a new combination of the three dimensional linear method and the transfer matrix method. Both saturation and finite length effects are taken into account. The active region of the solid rotor is divided into saturated and unsaturated parts. The time dependence is assumed to be sinusoidal and phasor quantities are used in the solution. The method is applied to the calculation of smooth solid rotors manufactured of different materials. Six rotor materials are tested: three construction steels, pure iron, a cobaltiron alloy and an aluminium alloy. The results obtained by the method agree fairly well with the measurement quantities.

Cooling system optimization in medium-speed engines

Tässä työssä optimoidaan keskinopean Wärtsilä 32 -dieselmoottorin jäähdytysjärjestelmää ja tutkitaan taajuusmuuttajien käyttömahdollisuutta kiertopumppujen yhteydessä niin, että järjestelmässä saataisiin kiertämään vain kulloinkin tarvittava määrä vettä. Tutkimuksen mallinnus on toteutettu laatimalla aiemmin käytössä olleista yksinkertaisista simulointimalleista yksi malli, johon on sisällytetty sekä virtauksen että lämmönsiirron laskenta, jotka on aiemmin mallinnettu erillisillä ohjelmilla. Diplomityö on osa projektia, joka on tehty Sähkötekniikan osaston tutkijan Mikko Pääkkösen kanssa yhteistyössä. Tämän diplomityö keskittyy lähinnä virtausteknisiin ja lämmönsiirtoon liittyviin asioihin, kun taas sähkötekniikan osuus on esitetty Mikko Pääkkösen raportissa. Tulosten perustella voidaan sanoa, että taajuusmuuttajakäyttö kannattaa kiertopumppujen yhteydessä. Käyttämällä pumppujen virtaussäätöä voidaan jäähdytysjärjestelmästä jättää monia komponentteja, kuten termostaattiventtiilejä pois. Mallinnetut yksinkertaiset piiriratkaisut näyttävät toimivan ainakin yleisellä tasolla. Tutkimusta pumppujen säädöstä ja tässä projektissa luoduista jäähdytysjärjestelmäkonfiguraatioista kannattaa jatkaa.

High-Speed Solid-Rotor Induction Machine – Electromagnetic Calculation and Design

Within the latest decade high-speed motor technology has been increasingly commonly applied within the range of medium and large power. More particularly, applications like such involved with gas movement and compression seem to be the most important area in which high-speed machines are used. In manufacturing the induction motor rotor core of one single piece of steel it is possible to achieve an extremely rigid rotor construction for the high-speed motor. In a mechanical sense, the solid rotor may be the best possible rotor construction. Unfortunately, the electromagnetic properties of a solid rotor are poorer than the properties of the traditional laminated rotor of an induction motor. This thesis analyses methods for improving the electromagnetic properties of a solid-rotor induction machine. The slip of the solid rotor is reduced notably if the solid rotor is axially slitted. The slitting patterns of the solid rotor are examined. It is shown how the slitting parameters affect the produced torque. Methods for decreasing the harmonic eddy currents on the surface of the rotor are also examined. The motivation for this is to improve the efficiency of the motor to reach the efficiency standard of a laminated rotor induction motor. To carry out these research tasks the finite element analysis is used. An analytical calculation of solid rotors based on the multi-layer transfer-matrix method is developed especially for the calculation of axially slitted solid rotors equipped with wellconducting end rings. The calculation results are verified by using the finite element analysis and laboratory measurements. The prototype motors of 250 – 300 kW and 140 Hz were tested to verify the results. Utilization factor data are given for several other prototypes the largest of which delivers 1000 kW at 12000 min-1.

Lectio praecursoria: Environmental policy evaluation concepts exemplified in the context of the European Unions strategy for better regulation

Lectio praecursoria 3.2.2006 Tampereen yliopisto

Competitor comparison: variable speed drives in pumping applications

As the world’s energy demand is increasing, a durable solution to control it is to improve the energy efficiency of the processes. It has been estimated that pumping applications have a significant potential for energy savings trough equipment or control system changes. For many pumping application the use of a variable speed drive as a process control element is the most energy efficient solution. The main target of this study is to examine the energy efficiency of a drive system that moves the pump. In a larger scale the purpose of this study is to examine how the different manufacturers’ variable speed drives are functioning as a control device of a pumping process. The idea is to compare the drives from a normal pump user’s point of view. The things that are mattering for the pump user are the efficiency gained in the process and the easiness of the use of the VSD. So some thought is given also on valuating the user-friendliness of the VSDs. The VSDs are compared to each other also on the basis of their life cycle energy costs in different kind of pumping cases. The comparison is made between ACS800 from ABB, VLT AQUA Drive from Danfoss, NX-drive from Vacon and Micromaster 430 from Siemens. The efficiencies are measured in power electronics laboratory in the Lappeenranta University of Technology with a system that consists of a variable speed drive, an induction motor with dc-machine, two power analyzers and a torque transducer. The efficiencies are measured as a function of a load at different frequencies. According to measurement results the differences between the measured system efficiencies on the actual working area of pumping are on average few percent units. When examining efficiencies at the whole range of different loads and frequencies, the differences get bigger. At low frequencies and loads the differences between the most efficient and the least efficient systems are at the most about ten percent units. At the most of the tested points ABB’s drive seem to have slightly better efficiencies than the other drives.

Performance benchmarking and incentive regulation – considerations of directing signals for electricity distribution companies

After the restructuring process of the power supply industry, which for instance in Finland took place in the mid-1990s, free competition was introduced for the production and sale of electricity. Nevertheless, natural monopolies are found to be the most efficient form of production in the transmission and distribution of electricity, and therefore such companies remained franchised monopolies. To prevent the misuse of the monopoly position and to guarantee the rights of the customers, regulation of these monopoly companies is required. One of the main objectives of the restructuring process has been to increase the cost efficiency of the industry. Simultaneously, demands for the service quality are increasing. Therefore, many regulatory frameworks are being, or have been, reshaped so that companies are provided with stronger incentives for efficiency and quality improvements. Performance benchmarking has in many cases a central role in the practical implementation of such incentive schemes. Economic regulation with performance benchmarking attached to it provides companies with directing signals that tend to affect their investment and maintenance strategies. Since the asset lifetimes in the electricity distribution are typically many decades, investment decisions have far-reaching technical and economic effects. This doctoral thesis addresses the directing signals of incentive regulation and performance benchmarking in the field of electricity distribution. The theory of efficiency measurement and the most common regulation models are presented. The chief contributions of this work are (1) a new kind of analysis of the regulatory framework, so that the actual directing signals of the regulation and benchmarking for the electricity distribution companies are evaluated, (2) developing the methodology and a software tool for analysing the directing signals of the regulation and benchmarking in the electricity distribution sector, and (3) analysing the real-life regulatory frameworks by the developed methodology and further develop regulation model from the viewpoint of the directing signals. The results of this study have played a key role in the development of the Finnish regulatory model.

Developing of the Variable Speed Drive -control in simulated parallel pumping systems

This thesis presents briefly the basic operation and use of centrifugal pumps and parallel pumping applications. The characteristics of parallel pumping applications are compared to circuitry, in order to search analogy between these technical fields. The purpose of studying circuitry is to find out if common software tools for solving circuit performance could be used to observe parallel pumping applications. The empirical part of the thesis introduces a simulation environment for parallel pumping systems, which is based on circuit components of Matlab Simulink —software. The created simulation environment ensures the observation of variable speed controlled parallel pumping systems in case of different controlling methods. The introduced simulation environment was evaluated by building a simulation model for actual parallel pumping system at Lappeenranta University of Technology. The simulated performance of the parallel pumps was compared to measured values of the actual system. The gathered information shows, that if the initial data of the system and pump perfonnance is adequate, the circuitry based simulation environment can be exploited to observe parallel pumping systems. The introduced simulation environment can represent the actual operation of parallel pumps in reasonably accuracy. There by the circuitry based simulation can be used as a researching tool to develop new controlling ways for parallel pumps.

Power line communication in motor cables of variable-speed electric drives − analysis and

Data transmission between an electric motor and a frequency converter is required in variablespeed electric drives because of sensors installed at the motor. Sensor information can be used for various useful applications to improve the system reliability and its properties. Traditionally, the communication medium is implemented by an additional cabling. However, the costs of the traditional method may be an obstacle to the wider application of data transmission between a motor and a frequency converter. In any case, a power cable is always installed between a motor and a frequency converter for power supply, and hence it may be applied as a communication medium for sensor level data. This thesis considers power line communication (PLC) in inverter-fed motor power cables. The motor cable is studied as a communication channel in the frequency band of 100 kHz−30 MHz. The communication channel and noise characteristics are described. All the individual components included in a variable-speed electric drive are presented in detail. A channel model is developed, and it is verified by measurements. A theoretical channel information capacity analysis is carried out to estimate the opportunities of a communication medium. Suitable communication and forward error correction (FEC) methods are suggested. A general method to implement a broadband and Ethernet-based communication medium between a motor and a frequency converter is proposed. A coupling interface is also developed that allows to install the communication device safely to a three-phase inverter-fed motor power cable. Practical tests are carried out, and the results are analyzed. Possible applications for the proposed method are presented. A speed feedback motor control application is verified in detail by simulations and laboratory tests because of restrictions for the delay in the feedback loop caused by PLC. Other possible applications are discussed at a more general level.

Mitotic regulation by Polo-like kinase 1 and the Chromosomal Passenger Complex

During mitosis, the duplicated genome must be accurately divided between two daughter cells. Polo-like kinase 1 (Plk1) and Aurora B kinase, together with its binding partners Incenp, Survivin and Borealin (chromosomal passenger complex, CPC), have key roles in coordinating mitotic events. The accuracy of cell division is safeguarded by a signaling cascade termed the mitotic spindle checkpoint (SC), which ensures that chromosomes are not physically separated before correct bipolar attachments have been formed between kinetochores and spindle microtubules (MT). An inhibitory “wait anaphase” signal, which delays chromosome separation (anaphase onset), is created at individual kinetochores and broadcasted throughout the cell in response to lack of kinetochore-microtubule (kMT) attachment or proper interkinetochore tension. It is believed that the fast turnover of SC molecules at kinetochores contributes to the cell’s ability to produce this signal and enables rapid responses to changing cellular conditions. Kinetochores that lack MT attachment and tension express a certain phosphoepitope called the 3F3/2 phosphoepitope, which has been linked to SC signaling. In the experimental part, we investigated the regulation of the 3F3/2 phosphoepitope, analyzed whether CPC molecules turn over at centromeres, and dissected the mitotic roles of the CPC using a microinjection technique that allowed precise temporal control over its function. We found that the kinetochore 3F3/2 phosphoepitope is created by Plk1, and that CPC proteins exhibit constant exchange at centromeres. Moreover, we found that CPC function is necessary in the regulation of chromatid movements and spindle morphology in anaphase. In summary, we identified new functions of key mitotic regulators Plk1 and CPC, and provided insighs into the coordination of mitotic events.

Power Consumption in Carbon Capture and Storage Systems (CCS) and Possibilities to Reduce Power Consumption with Variable Speed Drives

The aim of this master´s thesis is to study which processes increase the auxiliary power consumption in carbon capture and storage processes and if it is possible to reduce the auxiliary power consumption with variable speed drives. Also the cost of carbon capture and storage is studied. Data about auxiliary power consumption in carbon capture is gathered from various studies and estimates made by various research centres. Based on these studies a view is presented how the power auxiliary power consumption is divided between different processes in carbon capture processes. In a literary study, the operation of three basic carbon capture systems is described. Also different methods to transport carbon dioxide and carbon dioxide storage options are described in this section. At the end of the thesis processes that consume most of the auxiliary power are defined and possibilities to reduce the auxiliary power consumption are evaluated. Cost of carbon capture, transport and storage are also evaluated at this point and in the case that the carbon capture and storage systems are fully deployed. According to the results, it can be estimated what are the processes are where variable speed drives can be used and what kind of cost and power consumption reduction could be achieved. Results also show how large a project carbon capture and storage is if it is fully deployed.

Negative Regulation of Receptor Tyrosine Kinases by T-cell Protein Tyrosine Phosphatase

Protein tyrosine phosphorylation controls a wide array of cellular responses such as growth, migration, proliferation, differentiation, metabolism and cytoskeletal organisation. Tyrosine phosphorylation is a dynamic process involving the competing activities of protein tyrosine kinases and protein tyrosine phosphatases. The protein tyrosine kinases are further divided into non-receptor- and receptor tyrosine kinases. The latter are transmembrane glycoproteins activated by the binding of specific ligands, mostly growth factors, to their extracellular domain, transmitting different signals to the cell. Growth factor receptors such as the epidermal growth factor receptor, vascular endothelial growth factor receptor 2 and platelet-derived growth factor receptor β, belong to the receptor tyrosine kinases, the signalling of which is often disturbed in various diseases, including cancer. This has led to the development of receptor tyrosine kinase antagonists for use as anti-cancer drugs. As the receptor tyrosine kinases, also the protein tyrosine phosphatases can be divided into receptor- and non-receptor types. The protein tyrosine phosphatases have attained much less attention than the receptor tyrosine kinases partly because they were identified later. However, accumulating evidence shows that the protein tyrosine phosphatases have important roles as specific and active regulators of tyrosine phosphorylation in cells and of physiological processes. Consequently, the protein tyrosine phosphatases are receiving arising interest as novel drug targets. The aim of this work was to elucidate the negative regulation of receptor tyrosine kinases by one non-receptor protein tyrosine phosphatase, T-cell protein tyrosine phosphatase TCPTP. The results show that TCPTP activated by cell adhesion receptor integrin α1 functions as a negative regulator of the epidermal growth factor receptor. It was also found that TCPTP affects vascular endothelial growth factor receptor 2 signalling and angiogenesis. Lastly, a High-throughput screen with 64,280 compounds was performed to identify novel TCPTP activators, resulting in identification of one small molecule compound capable of exerting similar effects on TCPTP signalling as integrin α1. This compound is shown to downregulate signalling of epidermal growth factor receptor and platelet-derived growth factor receptor β, as well as to inhibit cell proliferation and angiogenesis. Our results suggest that a suitable small-molecule TCPTP activator could be utilized in the development of novel anti-cancer drugs.

β1 integrin regulation

Integrins are heterodimeric adhesion receptors mediating adhesion to extracellular matrix proteins and to other cells. Integrins are important in embryonic development, structural integrity of connective tissue, blood thrombus formation, and immune defense system. Integrins are transmembrane proteins whose ligand binding capacity (activity) is regulated by large conformational changes. Extracellular ligand binding or intracellular effector binding to integrin cytoplasmic face regulate integrin activity. Integrins are thus able to mediate bi-directional signaling. Integrin function is also regulated by intracellular location. Integrins are constantly recycled from endocytic vesicles to plasma membrane, and this has been shown to be important for cell migration and invasion as well. Deregulation of integrin functionality can lead to deleterious illnesses, such as bleeding or inflammatory disorders. It is also evident that integrin deregulation is associated with cancer progression. In this study, a novel Beta1 integrin associating protein, Rab21, was characterized. Rab21 binding to integrin cytoplasmic tail was shown to be important for Beta1 integrin endo- and exocytosis – intracellular trafficking. It was furher shown that this interaction has an important role in cell adhesion, migration, as well as in the final step of cell division, cytokinesis. This work showed that abrogation of Rab21 function or β1 integrin endocytic traffic, can lead to defects in cell division and results in formation of multinucleated cells. Multinucleation and especially tetraploidy can be a transient pathway to aneuploidy and tumorigenesis. This work characterized chromosomal deletions in rab21 locus in ovarian and prostate cancer samples and showed that a cell line with rab21 deletion also had impairment in cell division, which could be rescued by Rab21 re-expression. The work demonstrates an important role for Rab21 and Beta1 integrin traffic regulation in cell adhesion and division, and suggests a probable associaton with tumorigenesis. In this study, Beta1 integrin activity regulation was also addressed. A novel cell array platform for genome-scale RNAi screenings was characterized here. More than 4500 genes were knocked-down in prostate cancer cells using siRNA-mediated silencing. The effects on Beta1 integrin activity were analyzed upon knock-downs. The screen identified more that 400 putative regulators of Beta1 integrin activity in prostate cancer. In conclusion, this work will help us to understand complex regulatory pathways involved in cancer cell adhesion and migration.

Energy efficiency parameters in variable speed drives

The main purpose of this thesis is to measure and evaluate how accurately the current energy saving calculation in ABB’s new variable speed drive ACS850 works. The main topic of this thesis is energy-efficiency parameters. At the beginning of this thesis centrifugal pump, squirrel cage motor and variable speed drive, including some equations related to them, are being introduced. Also methods of throttling control and variable speed drive control of centrifugal pumps are being introduced. These subjects are introduced because the energy saving calculation in ACS850 is related to the centrifugal pumps usually driven by squirrel cage motors. The theory also includes short section about specific energy of pumping. Before measurements the current energy saving calculation of ACS850 is being introduced and analyzed. The measurements part includes introduction of measuring equipment, measurement results, summary and analysis of the measurements. At the end of this thesis a proposal for an improvement to the current energy saving calculation is being introduced and few proposals are made for new energy-efficiency parameters, which could be added to variable speed drives. At the end are also thoughts

Differential Regulation of c-FLIP Isoforms Through Post-translational Modifications

Cells are constantly responding to signals from the surrounding tissues and the environment. To dispose of infected and potentially dangerous cells, to ensure the optimal execution of developmental processes and to maintain tissue homeostasis, a multicellular organism needs to tightly control both the number and the quality of its cells. Apoptosis is a form of active cellular self-destruction that enables an organism to regulate its cell number by deleting damaged or potentially dangerous cells. Apoptosis can be induced by death ligands, which bind to death receptors on the cell surface. Ligation of the receptors leads to the formation of an intracellular death inducing signaling complex (DISC). One of the DISC components is caspase-8, a protease that triggers the caspase cascade and is thereby a key initiator of programmed cell death. The activation of caspase-8 is controlled by the cellular FLICE-inhibitory proteins (c-FLIPs). Consequently, sensitivity towards receptor-mediated apoptosis is determined by the amount of c-FLIP, and the c-FLIP levels are actively regulated for example during erythroid differentiation of K562 erythroleukemia cells and by hyperthermia in Jurkat leukemia cells. The aim of my thesis was to investigate how c-FLIP is regulated during these processes. We found that c-FLIP isoforms are short-lived proteins, although c-FLIPS had an even shorter half-life than c-FLIPL. In both experimental models, increased death receptor sensitivity correlated with induced ubiquitylation and consequent proteasomal degradation of c-FLIP. Furthermore, we elucidated how phosphorylation regulates the biological functions and the turnover of c-FLIP, thereby contributing to death receptor sensitivity. We mapped the first phosphorylation sites on c-FLIP and dissected how their phosphorylation affects c-FLIP. Moreover, we demonstrated that phosphorylation of serine 193, a phosphorylated residue common to all c-FLIPs, is primarily mediated by the classical PKC. Furthermore, we discovered a novel connection between the phosphorylation and ubiquitylation of c-FLIP: phosphorylation of S193 protects c-FLIP from ubiquitylation. Surprisingly, although all c-FLIP isoforms are phosphorylated on this conserved residue, the biological outcome is different for the long and short isoforms, since S193 specifically prolongs the half-lives of the short c-FLIP isoforms, but not c-FLIPL. To summarize, we show that c-FLIP proteins are modified by ubiquitylation and phosphorylation, and that the biological outcomes of these modifications are isoform-specifically determined.