Introduction
The aim of this project is to build a flywheel that will store and release electrical energy.
Introduction to flywheels
The concepts used in flywheels have been around since the invention of the wheel: a flywheel is a spinning disc that stores energy through its rotation.
Modern flywheel batteries are often used in long-term energy storage solutions and are usually highly massive to optimize energy loss thanks to their high moment of inertia. To store energy, a motor is used to convert electrical energy into mechanical rotational energy through the spinning of the flywheel. In order to release energy, the motor works in reverse as a generator, slowing the rotation of the flywheel.
The flywheel is either levitated using magnetic bearings or attached to very well oiled mechanical bearings, minimizing energy losses due to friction.
Design choices
The project is built around a Manfrotto compact action tripod that will be used as the support for the rest of the build. The head of the tripod is removed, and a threaded inox steel tube is passed through the hole in the middle of the tripod. The flywheel itself is a relatively thin fiberglass disc with a radius of around 10 cm. Screws are added around the outside of the flywheel to increase the moment of inertia, and the flywheel is inserted into the steel tube and fixed in place with nuts.
The flywheel is therefore supported vertically. In order to support the weight of the tube, a sharp end is added at the bottom. This sharp end is placed on metal in order to minimize energy loss due to friction. Vertical alignment is ensured thanks to a circular magnet fitted into the tube. All around this magnet are repelling magnets that ensure that the tube stays perfectly vertical and does not drift from side to side.
A homemade brushless motor is used to store and extract energy from the flywheel. It consists of a rotor and a stator which are explained in depth in the mechanics page.