Power generators technology
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The production of whole electric machines, or of parts of them, is the main activity of our company.
Let us analyze in detail the most important aspects of the production of the most requested electromechanic machines:

Stator: Frame
The frame is made from high quality steel sheets, which are welded and stiffened by a suitable number of longitudinal and transversal ribs. The inside of the stator frame is a part of the cooling ducts, therefore the existing ribs are arranged in order to allow an optimum air flow. If necessary, the frame inside is coated with acoustic insulation panels in order to reduce noise in the engine room.

Stator: Magnetic core
The pack or magnetic core is made from low loss digit laminations, which are duly trimmed and insulated on both sides. The slots of the magnetic core are of an open kind and the profile of the tooth laminations will be as such to ensure the utmost tightness of the press-winding wedges as regards radius stresses. Groups of laminations are joined together in order to form differet elementary packs of which the magnetic core consists. Between the different small packs a suitable number of spacers is inserted, in order to create channels having the function of cooling the small pack and the stator winding, as well as limited load losses. The magnetic core is anchored between plates under pressure and is fixed to the frame by dovetails or similar devices.

Stator: winding
The stator winding is of the short, double layer pitch kind. The turn is made from electrolytic, drawn, annealed copper straps with rounded edges and suitably insulated. The straps are not so thick, in order to reduce the losses due to power density. It is possible to carry out stator winding in two ways:
- Global VPI
Porous tapes are used which, during the vacuum impregnation process, absorb the injected resin which then fills all the slots, in order to give compactedness and resistance to insulation. The advantages of this technology are the speed of the process and its low cost. Unfortunately, since it is a global impregnation, after such an operation, it is not possible to intervene (tests, repairs, replacements,etc.) on one coil, since that the whole winding has become an only unit.
- Resin Rich
Tapes pre-impregnated with resin are used. When during thermo-pressing procedure of the active sides of the coil, the resin comes out, it fills all the air pockets and gives compactedness and electrical resistance to insulation. The advantages of this technology are represented by the possibilità of intervening, if it is necessary, on each single coil (tests, repairs, replacements, etc.),since that each single coil is thermo-pressed and insulated.

Rotor: Shaft
The rotor shaft is made from a forged or rolled section, in order thatit has got mechanic and magnetic characteristics. All the materials of which it is made are carefully selected, in order to resist the biggest stresses that can occur, because of centrifugal force, during conditions of runaway speed. For the mechanic sizing of the shaft analyses of the critical torsional and flexural frequences are carried out.

Rotor: poles
Poles consist of trimmed steel laminations, having high mechanic and magnetic characteristics, the thickness of which is suitable for the machine characteristics.

Rotor: winding
Rotor winding consists of electroytic copper straps. Turns are obtained from the brazing of copper dishes, while the insulation between the coil turns is represented by interlayers of twin-enamelled Nomex. Coils are suitably processed and hot pressed before assembling, in order to make them be compact and to avoid sags even at utmost stresses due to runaway speed. If necessary, coils can have a suitable number of projecting turns, in order to increase the surface of thermal exchange between copper and cooling fluid. Coil assembling on the polar pack is carried out in order to ensure a perfect insulation between copper and core.

Rotor: bearings
Bearings will be able to bear the weight of all the rotating parts of the machine and any possible residual thrust of it and of the corresponding hydraulic turbine. Bearings are of the white metal kind (friction)or of the roller (rolling) kind, with autonomous lubrication in oil or grease bath, and are provided with rigid seals, made from a material resistant to corrosion and suitable for the degree of protection required. All the active parts of the supports are assembled in a caisson.
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