This thesis is the result of the investigation and solution of a mechanicalproblem regarding Flywheel malfunctions. A Flywheel is, in short, a devicethat relies on a rotating object?s moment of inertia to store energy overshort time spans. This project is part of the development of a fourthFlywheel prototype at the division for electricity at Uppsala university,which uses magnetic levitation to keep a hollow cylinder rotating at veryhigh speeds inside a vacuum chamber. Should the magnets fail however, orsome other error occur that leads to an uncontrolled state of rotation, thecylinder needs to be stabilized mechanically by a device usually referredto as ?back-up bearing?.

Storing kinetic energy in a Flywheel allows for more efficient driving of electricvehicles. Research in this area is in progress at Uppsala University, where a Flywheelwith magnetic bearings encased in a vacuum chamber is being constructed. To makethis possible methods for measuring the current through the electromagnets in thebearings and temperatures in the Flywheel need to be developed. This has been thepurpose of this report. The current measurement resulted in a resistive method, andthe implementation of eight measurement circuits in the system.

To conclude this year?s introductory course in Mechatronics the students, in groups of 6,constructed a prototype based on the technical requirements established by the course teachers.This year they consisted of the following: two wheels only, active balancing, remote controlledand able to stop when crossing a pre-determined marker on the ground. The project lasted for 7weeks and the result is a working prototype and this report.The report reviews the chosen solution, subsystems and the finished prototype as well assuggestions for improvements, discussion and analysis.The prototype constructed embodied most of the group?s earlier individual technical specialtiesand consists of the following: a Flywheel for balancing, ultrasound for angle measurement, areflective photomicrosensor to detect the marker and Bluetooth for the hand control..

Örebro svets & hydraulik AB tillverkar lastknektar till Suzuki Garphyttan. På lastknektarna transporteras sedan stora rullar av tråd i stål. Knektarna har visat sig kollapsa efter viss tids användning och behöver därför en förbättrad konstruktion. Höga laster, tuff hantering samt ovarsamma lyft kan vara orsaker till att knektarna kollapsar. Örebro svets är väl införstådda var skadorna uppstår i nuvarande konstruktion och vill därför förstärka denna del och konstruktionen i sin helhet.Kraven på den nya konstruktionen, förutom att vara mer hållbar, är att befintligt mått mellan benen ska följas och att knekten ska vara staplingsbar vid transport till galvanisering.Nuvarande knektar har modellerats i CAD-programmet Pro/ENGINEER för att sedan analyseras med Finita Elementmetoden i beräkningsprogrammet ANSYS för att visa var deformation och spänningar uppstår.

There is always a need for more effective ways to store energy in order to reduce the human impact on the environment. One step on the way can be the use of Flywheels as kinetic energy storage devices. Low frictional losses are essential for a Flywheel to be effective. To minimize these losses active magnetic bearings (AMB) can be used to keep the shaft centered instead of the more conventional ball-bearings. AMBs use actuators and a fast control system that needs correct and noise-free measurement data of the shaft position and the current in the actuators to work properly.This thesis explains the process of constructing power electronics and a current measurement system for active magnetic bearings (AMB).