They are free from contact and therefore free from wear.īall bearings represent a simpler, more common, less expensive alternative to active magnetic bearings but are challenged by the life and load requirements of flywheels. Active magnetic bearings levitate and actively position the rotor. The two most prevalent types of bearings found in flywheel systems are active magnetic bearings and ball bearings. Since the flywheel operates in vacuum or reduced pressure, thermal management and lubrication are also difficult. The need to support the greater weight of the rotor leads to the use of larger bearings which have greater drag losses and inherently poorer life than smaller bearings. Flywheel rotors tend to be unusually heavy when compared with other rotating machines operating at comparable speed. Bearing requirements tend to be more severe for flywheels than for other rotating machines and bearings are usually the life-limiting element in a flywheel design. A goal in rib design is to prevent the formation of a heavy mass of material that can result in a sink, void, distortion, long cycle time, or any combination of these problems.ĭonald Bender, in Storing Energy, 2016 4.2 Bearingsīearings support the flywheel rotor while allowing it to spin freely. In areas where structure is more important than appearance, or with very low shrinkage materials, ribs are often 75 or even 100% of the outside wall's thickness. With ribs opposite appearance areas, the width should be kept as thin as possible. The most general approach is to make the rib thickness at its base a minimum of one-half the adjacent wall's thickness. There are available basic engineering rib-design guidelines.

The moment of inertia can be changed substantially by adding ribs and other shapes such as gussets as well as their combinations. By finding a cross section with the two equivalent factors, one ensures equal or better performance of the fabricated product. Handbooks reviewing Stress and Deflections in Beams and Moments of Inertia provide information such as the moment of inertia and resistance to deflection that expresses the resistance to stress by the section modulus.

Rib scaffolding design guidelines