Psykologia

Psykologian pääkokoelma sijaitsee pääkirjastossa (Linnassa), jossa painettu yleis- ja käsikirjastokokoelma koostuu noin 7200 nimekkeestä monografioita (painettujen monografiasarjojen osat mukaan lukien). Psykologia-kokoelmasta noin 2/3 käsitteli psykologian erikoisaloja ja 1/3 yleistä psykologiaa. Molemmista ryhmistä kartoitettiin kaksi osa-aluetta. Kehitys- ja lapsipsykologiaa käsitteli noin 1/5 kirjoista (1445 nimekettä), joten se oli selvin painopisteala. Kognitiivista & oppimisen psykologiaa käsitteli 14,6 % kirjoista (1050 nimekettä). Persoonallisuuden psykologian (9,5 % / 683 nimekettä) sekä tunteiden & emootioiden (5,6 % / 400 nimekettä) osuudet kirjakokoelmasta olivat pienehköjä. Käsikirjaston karsitussa noin 100 nimekkeen kokoelmassa on hakuteoksia, sanastoja, bibliografioita jne. Painettuja lehtiä oli 11 nimekettä (Behavior Analyst, Cognition and Emotion, Mielenterveys, Perceptual and Motor Skills, Perheterapia, Psychological Reports, Psychotherapy Research, Psykologi, Psykologia, Ryhmätyö ja Voltti). Sähkökirjoja kokoelmassa oli 22 nimekettä NetLibrary-tietokannassa, noin 487 nimekettä Ebrary-tietokannassa sekä 3 nimekettä sähköisinä hakuteoksina (Encyclopedia of Applied Psychology, International Encyclopedia of the Social and Behavioral Sciences ja A Dictionary of Psychology). Verkkolehtiä kokoelmassa oli noin 450 nimekettä. Tietokantoja oli 4 kokotekstitietokantaa (PsycArticles, EbscoHost Academic Search Premier, Elsevier ScienceDirect ja Annual Reviews: Social Sciences) sekä 3 viitetietokantaa (PsycINFO, PsiTri ja Social Sciences Citation Index).

Induction motor versus permanent magnet synchronous motor in motion control applications: a comparative study

High dynamic performance of an electric motor is a fundamental prerequisite in motion control applications, also known as servo drives. Recent developments in the field of microprocessors and power electronics have enabled faster and faster movements with an electric motor. In such a dynamically demanding application, the dimensioning of the motor differs substantially from the industrial motor design, where feasible characteristics of the motor are for example high efficiency, a high power factor, and a low price. In motion control instead, such characteristics as high overloading capability, high-speed operation, high torque density and low inertia are required. The thesis investigates how the dimensioning of a high-performance servomotor differs from the dimensioning of industrial motors. The two most common servomotor types are examined; an induction motor and apermanent magnet synchronous motor. The suitability of these two motor types indynamically demanding servo applications is assessed, and the design aspects that optimize the servo characteristics of the motors are analyzed. Operating characteristics of a high performance motor are studied, and some methods for improvements are suggested. The main focus is on the induction machine, which is frequently compared to the permanent magnet synchronous motor. A 4 kW prototype induction motor was designed and manufactured for the verification of the simulation results in the laboratory conditions. Also a dynamic simulation model for estimating the thermal behaviour of the induction motor in servo applications was constructed. The accuracy of the model was improved by coupling it with the electromagnetic motor model in order to take into account the variations in the motor electromagnetic characteristics due to the temperature rise.

Converter-Fed Induction Motor Losses: Determination With IEC Methods

Energy efficiency is an important topic when considering electric motor drives market. Although more efficient electric motor types are available, the induction motor remains as the most common industrial motor type. IEC methods for determining losses and efficiency of converter-fed induction motors were introduced recently with the release of technical specification IEC/TS 60034-2-3. Determining the induction motor losses with IEC/TS 60034-2-3 method 2-3-A and assessing the practical applicability of the method are the main interests of this study. The method 2-3-A introduces a specific test converter waveform to be used in the measurements. Differences between the induction motor losses with a test converter supply, and with a DTC converter supply are investigated. In the IEC methods, the tests are run at motor rated fundamental voltage, which, in practice, requires the frequency converter to be fed with a risen input voltage. In this study, the tests are run on both frequency converters with artificially risen converter input voltage, resulting in rated motor fundamental input voltage as required by IEC. For comparison, the tests are run with both converters on normal grid input voltage supply, which results in lower motor fundamental voltage and reduced flux level, but should be more relevant from practical point of view. According to IEC method 2-3-A, tests are run at rated motor load, and to ensure comparability of the results, the rated load is used in the grid-fed converter measurements, although motor is overloaded while producing the rated torque at reduced flux level. The IEC 2-3-A method requires also sinusoidal supply test results with IEC method 2-1-1B. Therefore, the induction motor losses with the recently updated IEC 60034-2-1 method 2-1-1B are determined at the motor rated voltage, but also at two lower motor voltages, which are according to the output fundamental voltages of the two network-supplied converters. The method 2-3-A was found to be complex to apply but the results were stable. According to the results, the method 2-3-A and the test converter supply are usable for comparing losses and efficiency of different induction motors at the operating point of rated voltage, rated frequency and rated load, but the measurements do not give any prediction of the motor losses at final application. One might therefore strongly criticize the method’s main principles. It seems, that the release of IEC 60034-2-3 as a technical specification instead of a final standard for now was justified, since the practical relevance of the main method is questionable.