MAGNETIC CORE OF ELECTRIC ROTATIONAL MACHINES MADE OF GRAIN-ORIENTED SHEETS Technical Field This invention refers to design of laminated magnetic core of electric rotational machines (generators and motors) Laminated magnetic core of electric rotational machines is exposed to alternating (mostly sinusoidal) magnetic field. Alternating the direction of magnetic field generate the energy losses which heat the core. To decrease the losses and increase the efficiency of machine there is the need of use the materials with better magnetic characteristics. The material with the lowest energy losses is cold rolled grain oriented steel sheet. This material is not used in rotational machines because it has good characteristics only in one direction of magnetic field and in magnetic core of electrical rotational machines magnetic field has different directions even changing through the time.

Background art Existing design of magnetic core of electric rotational machines use grain-nonoriented sheets which has inferior characteristics than grain-oriented sheets but those characteristics are the same in all directions of magnetic field. Grain-oriented sheets are used only in transformers where the magnetic field is mostly in one direction and sheets can be adduced to the that direction.

Disclosure of invention Design of laminated magnetic core of electric rotational machines made of grain-oriented sheets is such that the core is divided in radial direction into two parts. First part are the teeth where direction of magnetic field is radial and second is joke where direction of magnetic field is mostly tangential. Joke part and teeth part are assemble together in one integral core.

The segment of stator sheet is cut out so that joke part and teeth part are cut out separately in such shape that end of tooth part fit into cut out shape of joke part. The shape of connection line of tooth and joke part is not the same from layer to layer. They are made so that they overlap from layer to layer (similar known term from transformer cores is step-lap). By that way the conducting contact at the sheets edges is avoid which means lower eddy-current losses. The same way the radial edges of joke part overlap form layer to layer.

Laminated magnetic core of electric rotational machines made of grain-oriented sheets in integral assembled form is the same shape as usual core so can be used in the same way.

Dawings Figure 1 Cross-section of usual magnetic circuit sinchronous electric salient-pole machine Figure 2 Usual sheet segment of rotational electric machine magnetic core Figure 3 Sheet segment of rotational electric machine magnetic core made of grain-oriented sheets Figure 4 Parts of sheet segment of rotational electric machine magnetic core made of grain-oriented sheets Figure 5 teeth overlap of two adjoining sheet layers List of drawings designations: 1-magnetic core of rotational electric machine 2-joke 3-grooves for coils 4-magnetic field direction 5-magnetic sheet direction 6-segment of joke part 8-segment of tooth part 9-cut out shape for connection of tooth part to joke part