The effects of filling the core box cavity and sand compaction in processes of core production by blowing methods (blowing, shooting)
depend on several main factors. The most important are: geometrical parameters of cavity and complexity of its shape, number,
distribution and shape of blowing holes feeding sands as well as the venting of a technological cavity. Values of individual parameters are
selected according to various criteria, but mostly they should be adjusted to properties of the applied core sand.
Various methods developed by several researchers, including the authors own attempts, allow to assess core sands properties on the basis
of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability
factor provide a better possibility of assessing the core sand behavior during flowing and core box filling, which indicate the value and
structure of the obtained compacting decisive – after hardening – for strength and permeability. The mentioned above aspects are analyzed
– on the basis of authors’ own examinations - in the hereby paper.
The paper presents research on the development of a line-start synchronous reluctance motor (LSSynRM) and line-start permanent magnet synchronous motor (LSPMSM) based on components of a mass-produced three-phase low-power squirrel cage induction motor (IM). The aim of the research was to modify the squirrel cage rotor structure for which the best functional parameters characterizing the steady state of the LSSynRM and LSPMSM were obtained, while meeting the additional requirements for asynchronous start-up. Field-circuit models of the LSSynRM and LSPMSM have been developed in the professional finite element method (FEM) package, MagNet, and applied in the design and optimization calculations of the considered machines. Experimental testing on the designed LSSynRM and LSPMSM prototypes were carried out. The obtained results were compared with the performance of the reference IM. The conclusions resulting from the comparative analysis of these three motors are given and proposals for further work are discussed.