DE3031159A1 - Short-circuit rotor cage for electrical machine - uses short-circuit bars with transverse bore or keying indentation at each end - Google Patents

Abstract

The rotor cage is made by inserting short-circuit bars (12) in the slots of the rotor stampings packet (11) so that these propel at either end of the latter. These projecting ends are joined together by short-circuit rings provided at each end of the rotor cage. These short-circuit rings are obtained by dipping the projecting ends in a metal smelt (15) subsequently cooled. The ends of the short-circuit rods (12) each have a transverse bore (13) or an annular indent to provide a secure key with the obtained short-circuit ring. Pref. an aluminium smelt (15) is poured into an annular mould (14) into which the short-circuit rods (12) are dipped, so that their bores (13) or indents are below its surface, but so that a given space is left between the smelt (15) and the end face of the rotor stampings packet (11).

Description

Process for the production of short circuit cafia

The invention relates to a method for manufacturing squirrel cages for the rotors of electrical machines with short-circuit rods in the grooves of laminated cores are used and the protruding on the end faces of the cage beyond the laminated core Short-circuit rods are connected to one another with a short-circuit ring each.

It is known, short-circuit cages for runners of large electrical machines by pressing copper profiles into the grooves provided in the rotor core and subsequent hard soldering of the short-circuit rods protruding beyond the rotor core manufacture with prefabricated short-circuit rings. The short circuit as a material rods and the short-circuit rings are preferably used copper or copper alloys. This is associated with high material costs.

In the main patent ... ... ... (patent application P 29 32 952.0) there is already a Process for the manufacture of short-circuit rotor cages for the electrical rotors Machines have been proposed in which short-circuit rods in the grooves of laminated cores are used and the protruding on the end faces of the cage beyond the laminated core Short-circuit rods are connected to each other with a short-circuit ring each, in which the ends of the short-circuit rods immersed centrally in an annular molten metal are, such that a predetermined distance between the end face of the laminated core and the surface of the molten metal is maintained that the temperature of the Molten metal is dimensioned so that the ends of the short-circuit rods are loosened and that when When the molten metal solidifies, a short-circuit ring is formed which encompasses the rod ends connects with each other.

The invention is based on the object, the method according to Main patent .. .. ... (patent application P 29 32 952.0) to the effect that an even better anchoring between the short-circuit ring and short-circuit rods is achieved will.

Based on a process as described in the main patent ... ... ... (patent application no. P 29 32 952.0) is described in more detail, the ends are used to solve this problem the short-circuit rods are provided with holes or undercuts.

The invention is based on the drawing and exemplary embodiments explained in more detail. It shows: FIG. 1 inserted in a schematic representation Short-circuit rods with bores or undercuts, Fig. 2 in schematic Representation of a laminated rotor core with short-circuit rods, the ends of which have holes provided are immersed in a molten metal.

Fig. 1 shows schematically laminated rotor stacks 11, which with bores 13 or various undercuts 16,17,18 are provided. The ends of the shorting rods 12 are with their bores 13 or undercuts 16,17,18 in a molten metal 15, for example, made of aluminum immersed in a ring shape 14.

Establishing the connection between short-circuit rods and short-circuit ring can be seen from FIG. A predetermined amount of aluminum 25 is in the ring shape 24 because of the good heat input and the good regularity Melt or melted aluminum into the by means of an inductive heating device Ring shape introduced and heated to a predetermined temperature and kept warm. The laminated rotor core 21 equipped with the short-circuit rods 22 is then centric lowered into the ring shape 24 to the extent that between the rising metal melt and the end face of the laminated rotor core 21 a distance a is maintained. the short sole rods 22 provided with bores 23, which for example consist of aluminum, are poured or cast around by the aluminum melt 25 and give the short-circuit ring an even better hold.

The advantage of the method of the invention is in dependence of the heat capacity of the short-circuit rods 22, the heat dissipation through the laminated core and other influencing factors such as heat radiation can be tempered in this way achieve that the immersed rods 22 at least with the same cross-section on the short-circuit ring be connected. The duration and temperature required for this are for the individual case, i.e. for the runner type, to be determined empirically. After switching off the heating power becomes the melt. 25 within the ring shape 24 in a short time, similar to normal Chill casting, solidify and so form the short-circuit ring. The runner can then removed from the ring mold 24, turned and for the casting of the short sole ring must be prepared on the opposite side of the runner.

1 claim 2 figures

Claims (1)

Claim method for manufacturing squirrel cages For the rotors of electrical machines, with short-circuit rods in the grooves of laminated cores are used and the protruding on the end faces of the cage beyond the laminated core Short-circuit rods are connected to one another with a short-circuit ring each, wherein the ends of the short-circuit rods are immersed centrally in an annular molten metal are, such that a predetermined distance between the end face of the laminated core and the surface of the molten metal is dimensioned so that the ends of the short-circuit rods are dissolved and that a short-circuit ring is formed when the molten metal solidifies which connects the rod ends with each other according to patent ... ... (patent registration P 29 32.952.0), it is noted that the ends of the short-circuit rods (12,22) can be provided with bores (13,23) or undercuts (16,17,18).