Abstract: In a large-diameter a.c. motor, the stator is divided by joints (6). The stator coil (5) consists of windings (4) which are arranged in two layers in the grooves of the stator. In order to simplify assembly of the machine, the stator coil (5) is divided into several zones (7) of closed windings (4) corresponding to the number of joints (6), which lie only in the grooves located between the joints. In the grooves adjacent to the joint (6), occupied with a winding side (8) in only one layer, the air gap is larger. Such a large-diameter a.c. motor, of synchronous or asynchronous design, can be advantageously used for variable-speed applications, for which the stator coil is supplied with current of varying frequency.

Abstract: The laminations of a laminated stator of a slowly running electrical machine having a high number of poles are composed of grain-oriented sheets, each of which has a preferential magnetic direction that extends substantially longitudinally along the teeth of that sheet. This permits the excitation current to be reduced, and, as a result, the air gap of the machine can be enlarged so that, on the whole, approximately the same excitation is required as for a laminated stator in which the laminations consist of normal, non-oriented sheets. As a result, the mechanical stability of the machine is increased. The invention is especially useful in asynchronous tube generators.

Abstract: An electrical machine in which power is supplied to the rotor via brushes and sliprings having an improved brush-dust suction apparatus, including brush supports and ring-shaped collecting chambers which are penetrated by brush bolts. The suction openings of these collecting chambers circumscribe the slipring in a ring pattern. Each collecting chamber is connected by thick-walled glass cylinders to a common collecting chamber, which is connected to a negative pressure source, when the air and the brush dust entrained in the air is conveyed to an exterior chamber. The brush supports are fastened by insulators to the collecting chamber and are mutually reinforced by insulator bolts.

Abstract: In a turbine set with an axial flow which is traversed by water and which is coupled to a generator feeding a network of constant frequency, the flow turbine is a propeller turbine with non-adjustable blades. The stator winding of the generator is connected to the network by means of a frequency-controllable converter, in particular a direct converter. The speed of rotation of the turbine set is controllable continuously according to the power to be delivered. In the case of an asynchronous design of the generator, it is advisable to provide the stator with a waterproof jacket on the inside and to flange it into the turbine tube, since the rotor with its cage winding is swept by water.

Abstract: A turbine type synchronous motor capable of starting directly and asynchronously when coupled to a work-performing machine is constructed with a drum rotor of high mass, made of solid magnetic material containing iron, and having no damper winding. The field windings, short-circuited or closed through a resistance during starting, are radially disposed in insulated slots which are closed by insulated wedges wherein the insulation is of highly temperature resistant material.

Abstract: A pressure plate for a liquid-cooled electric machine is disclosed which improves heat removal from the end-face region of the stator lamination stack. The pressure plate is provided with a cooling canal formed by a recess on the surface facing the stator lamination stack which is closed off by a cover plate. The cover plate may be provided with a rib on the surface facing the recess. In one embodiment, a plurality of juxtaposed recesses are provided which extend transversely to the pressure fingers of the pressure plate. The pressure plate is preferably made of stainless, non-magnetic steel, i.e., of austenitic chrome-nickel steel.

Abstract: In a synchronous electric machine with salient poles in its rotor, which are supported by a lamination chain, one sided large enlargements of the lamination chain deviating from a circular shape are prevented by straps arranged between the hub body and the lamination chain, the attachment of the straps at the lamination chain, with the machine standing still, being with a play which corresponds approximately to the mean expansion of the lamination chain at the runaway speed. If this play is taken up through expansion of the lamination chain due to one-sided forces, then the straps prevent further expansion. The invention is of advantage especially for slowly rotating hydroelectric generators.

Abstract: In a synchronous electric machine having a hollow rotor shaft, the dimensions for the seating surfaces of the shrink fit between the lamination ring and the hub are chosen so that lifting of the lamination ring at speeds above the nominal speed of rotation is limited to the portion of the axial length which is located on the side facing away from the turbine, while lifting below the nominal speed is provided in the region adjacent to the end face of the rotor on the turbine side. The rotor shaft is thus load-relieved, the lifting speed being determined so that the allowable material stress is not exceeded in that region.

Abstract: In an asynchronous machine including a rotor of solid iron and a squirrel cage winding, the rotor is further provided with closed slots of any cross sectional shape which receive the bars of the squirrel cage winding whose upper edge is spaced from the outer surface of the rotor by a distance which is equal to the depth of penetration a of the eddy currents generated for a given starting voltage and for a slip s.gtoreq.0.8.

Abstract: An excitation winding arrangement is provided for a synchronous electric machine having a rotor with shoeless, salient poles wherein the excitation windings are secured by slot wedges in gaps defined by the poles. Theexcitation winding arrangement includes coils which define the excitation winding and are formed by flat conductors. The flat conductors, either singly or in bundles, are held in spaced relation by respective combs at the bottom of the slots and under the slot wedge to form cooling ducts to achieve good air cooling of the excitation winding in the region of the pole gap.

Abstract: An excitation winding arrangement is provided for low-speed synchronous machines wherein the poles are configured without pole shoes and accommodate the excitation windings. The excitation winding arrangement includes coils of flat conductors which define the excitation windings. The flat conductors are wound so that their surfaces are parallel to the walls of the poles and the coils form a self-supporting component which can be improved by hardened turn insulation. These coils are secured only at the end-faces of the poles by a mounting arrangement. Effective cooling of the coils in the pole gap is thereby achieved.

Abstract: The support arrangement for a vertical electric machine includes a support spider thereof having arms fastened in a concrete wall surrounding the machine. The arms are secured only in the tangential direction. For this purpose, the arms extend into cavities of metal elements set into the concrete wall and are secured therein in the tangential direction by pretensioned rolling members. Because of the rolling motion of the rolling members, radial thermal expansion causes only relatively small radial forces to act and be transmitted to the concrete wall.

Abstract: The method includes maintaining the coolant circulation in a fluid-cooled hydropower generator also when the hydropower generator is shut down, and interrupting only the coolant circulation of the heat exchangers when the generator is in the shutdown condition. The leakage and conductivity control means of the circulation system are in constant operation.