Jämtkraft AB has recently modernized its hydropower station at Hissmofors by replacing four older worn out units with two new units. The generators uses a concept with sliding Stator feet to deal with the thermal movements that occur in the Stator during operation when the unit is operating intermittently. At other sites, this method revealed shortcomings in the reliability. This has made Jämtkraft AB feel uncertainty about its function and therefore want to investigate it during an early stage. The generators have a built-in monitoring system for the sliding Stator feet and by using data from there the function of the sliding Stator feet has been investigated. The study focused on how the different Stator feet move relative to each other and how the eccentricity and deviation from roundness changed during operation. The results show that there are several indications that the function of the sliding Stator feet is not satisfactory.

Jämtkraft AB which is a power production company in Sweden has bought two newhydro power units to their station in Hissmofors. The two new generators are using aconcept with sliding Stator feet to handle the thermal expansion.The concept with sliding Stator feet on hydro electric generators has not beenworking satisfactory on many hydro power stations in Sweden and has caused a lot ofcosts due to long downtimes.The new station in Hissmofors is very important for Jämtkraft AB, and therefore theywant to know how to make sure that the sliding Stator feet are working as theyshould. According to theories and a simplified model of the generator the Stator feetdisplacement should be around 1 -1,6 mm.The generators are delivered with a surveillance system that will measure thedisplacement of the sliding Stator feet. The signal from the system isn?t accessible forJämtkraft AB but it will alarm when the sliding Stator feet are malfunctioning.To secure the function of the sliding feet a logger for the surveillance system or adifferent measurement system must be used; if both systems are used Jämtkraft cansecure the function of the surveillance system..

At Uppsala university scientists have during the last years developed and built wave energy converters. This project is called "Lysekilsprojektet". The development has come so far that they are currently investigating how to gain profit in a mass production. For that reason they want to automate as many steps in the production as possible.The winding of the Stator is one part that is being automated using industry robots. The Stator is cable wound unlike many other generators.

This thesis concerns partial discharges in Stator windings and the possibility of analyzing data using statistical methods. Partial discharges, or PD, are a physical phenomenon in which discharges occur locally due to large electric fields. PD can occur in or adjacent to the insulation of Stator windings and causes breakdown of the insulating materials. PD measurement can provide an idea of how widespread the PD activity is. A technique to measure and analyze PD that has become very popular over the last few decades is phase resolved PD patterns.

Harmonics are a well-known problem that has to be dealt with in the design of thegenerator. Internationally accepted standards limits the amount of harmonics allowedin the no-load voltage. These limits can be difficult to fulfill with integral slot winding,where the number of slots per pole and phase is an integer. The presence of thedamper winding often makes the problem with harmonics even worse and harmonicswith frequencies of order 6q±1 arise with significant amplitude. How the damperwinding is designed affect the content of harmonics in the no-load voltage and the aimwith these ? has been to investigate in which extent design of the damper windingaffects the contents of harmonics.Simulations with the 2-D finite element method have showed that if the damper barsis centered in the pole shoe, the amplitude of the harmonics of order 6q±1dependsboth on the ratio between the Stator slot pitch and damper bars slot pitch and if thedamper bars are connected between the poles or not.If the damper bars is displaced with ¼ Stator slot pitch alternately, the amplitude ofthe harmonics of order 6q±1 is reduced and the influence of the ratio between theStator slot pitch and the damper bars slot pitch will vanish.

This thesis describes a method of measuring axial magnetic leakage flux in an operational hydropower generator. Axial magnetic leakage flux is the magnetic flux at the ends of a rotating generator, which goes through the Stator parallel to the rotor axis. This flux can cause circulating currents in the Stator iron, giving rise to losses, and can in the worst case overheat a generator, causing it to melt down. To measure the axial flux, and how it affects the generator temperature, a measurement system was constructed on behalf of Vattenfall. The system consists of search coil sensors and a signal-processing unit with amplifiers and active filtering.  To confirm the behaviour of the axial leakage flux and the functionality of the measurement system, a test installation was made.

This thesis concerns partial discharges in Stator windings and the possibility of analyzing data using statistical methods. Partial discharges, or PD, are a physical phenomenon in which discharges occur locally due to large electric fields. PD can occur in or adjacent to the insulation of Stator windings and causes breakdown of the insulating materials. PD measurement can provide an idea of how widespread the PD activity is. A technique to measure and analyze PD that has become very popular over the last few decades is phase resolved PD patterns.

The purpose with this thesis is to get a compilation of all the critical bolted joints of all enginesproduced at LV Motors. ABB LV Motors produces induction engines with seven shaft heights. Eachengine size exists several variants of components ex. standard shield and flange shield. Depending onwhich components the engine is equipped with arises various types of strains in the engine's parts,certain assembly ways are more favourable than other.The most critical parts in the engine from a mechanical point of view are the screw units betweenshield/Stator, feet/Stator and bearing cover/shield.

This thesis is an evaluation of a new design concept for Statorfeets in Gallejaur hydro power plant. Founder of the work is Vattenfall AB Vattenkraft. During the 70- and 80´s nuclear power began to be phased in to the Swedish grid, which meant that hydropower became an important source of rules. The generators began running in so called intermittent operations instead of basic operations, which meant 300-600 start/stop per year instead of one-ten numbers start/stop per year. In order to deal with the thermal forces that arise at every start and stop suppliers began to mount so called sliding joints, which is to take advantage of these forces and maintain the Stator shape.

This report is the result of a thesis carried out at the Department of Innovation, Design and Technology (IDT), at Mälardalen University on behalf of ABB AB Machines.The year was 1988 when ASEA and Brown Boveri formed a joint venture under the name ABB (Asea Brown Boveri).We perform our thesis at the division Discrete Automation and Motion where they primarily develops, manufactures and sells synchronous and asynchronous AC motors and generators.The main purpose of this thesis was initially to write a general packaging instruction, but the priority changed to develop more specific packaging instructions for Rotors, Stator gables, Bearing support and Outer Cover (plates) instead.The work started off to deal with a problem about that the staff had to start its work to grind away rust on the Stator gables due to those stored outdoors. The result was mainly an investment in a new gable rack so that the material can be stored inside, as well as a packing instruction as it was originally intended.The problem on the bearing supports were that the staff thought it was demanding and difficult to clean them from the rustproofing they were greased in. If it is not possible to remove all rust protection it can cause the paint to not attach properly. After having compared with similar articles a test were done to order a pair of bearing supports without corrosion inhibitor, which gave good results. This initiative also set in motion a process to do the same for more different items.For special pallet, a survey were made of the process with two different VSM and a calculation of how much ABB would earn at ordering more special pallets than getting the material delivered on the A-pallets.

ITT Flygt tillverkar framförallt dränkbara pumpar och omrörare. Motorerna till Flygts pumpar levereras av elmotorverkstaden där tillverkning av Statorer sker såväl med modern, högteknologisk lindningsutrustning som manuellt. Vid själva idraget av koppartråd i Statorn uppkommer oönskat höga idragningskrafter som anses både skada koppartråden samt generera ett ökat maskinslitage. Examensarbetets syfte var att identifiera vilka parametrar som påverkar idragningskraften samt att rekommendera parameterinställningar för att minska denna kraft. Rapporten syftar även till att vara ett stöd vid fortsatt användning av statistisk försöksplanering..

This report describes a synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a synchronous machine with its excitationsystems, e.g.

This report describes a synchronous machine model with magnetic saturation in d-axis, neutralconnection and electrical exciter interface for the transient simulator PSCAD/EMTDC. It hasbeen designed and verified in comparison to the regular machine model in EMTDC.The performance of the model is very good when incorporating a linear as well as a saturatedmagnetising inductance. The dynamic deviation is only thousandths to ten thousandths perunit. By using a cubic interpolation of the saturation curve, the model gives a good representationof the saturation effect. The open source code implementation of the synchronousmachine model gives the possibility to easily adapt the model to specific requirements.The derived model makes it possible to simulate a synchronous machine with its excitationsystems, e.g.

Ett relativt stort upprustnings- och förnyelseprogram pågår för att säkra framtida svensk vattenkraftproduktion och för att möta nya riktlinjer för dammsäkerhet. Under dessa förnyelseprojekt har vissa skador i form av sprickor i betongfundamenten upptäckts, bland annat kring Statorfötternas upplag. Orsaken till dessa sprickor härleds till Statorfötternas funktion, samt till temperaturvariationer vid förändrade driftsmönster. Tidigare gick generatorerna kontinuerligt medan det nu är vanligt med flera starter och stopp varje dygn. Denna rapport har som syfte att förtydliga det kraftspel som finns i dagens generatorfundament, att beräkna uppträdande spänningar och att försöka hitta data som bekräftar sprickbildningen.

I ett marint framdrivningssystem byggt av Rolls-Royce Marine i Kristinehamn, kallat POD Propulsion - MermaidTM, kyls systemets yttre delar med fo?rbistro?mmande vatten. Det kylande vattnet kompletteras av ett internt luftkylningssystem vilket, till fo?ljd av en la?gre kylningskapacitet a?n fo?r det externa vattnet, fo?rorsakar en otillra?cklig kylning i den sektor av elmotorns Stator vars periferi kyls av kylluftsstro?mmen. En andel av Statorn a?r sa?ledes enbart luftkyld vilket medfo?r att den axiella temperaturen i denna sektor uppna?r ett lokalt maximum, kallad ?hotspot?, vilken a?r ho?gre a?n fo?r resten av elmotorns Stator.Avsaknaden av en tangentiellt uniform temperatur i Statorn medfo?r begra?nsningar vid dimensionering av framdrivningssystemet.