Electric machine with rotor retaining rings

Abstract

The utility model relates to electrical engineering and can be used in the design of rotors of AC electric machines with excitation windings, primarily synchronous machines. The technical result of the proposed utility model is an increase in the specific power of the electric machine by increasing the slot fill factor with conductive material. The electric machine comprises a stator, a laminated rotor magnetic circuit with slots, and an excitation winding placed in the slots of the rotor magnetic circuit. The rotor magnetic circuit is axially divided by sheets whose outer diameter is smaller than the outer diameter of the rotor magnetic circuit stacks by the radial thickness of retaining rings installed on top of said sheets and overlapping the slots of the rotor magnetic circuit. A protective gasket is placed between the excitation winding and the retaining ring. 5 fig.

Description

[0001] The utility model relates to electrical engineering, in particular to the field of electrical engineering, and can be used in the design of rotors of AC electric machines with an excitation winding, primarily synchronous machines.

[0002] A rotor of an electric machine is known [Patent CN105680597 A, IPC H02K 1 / 32, H02K 3 / 34, H02K 1 / 26, H02K 3 / 46, published on 04 / 07 / 2020], which includes a laminated rotor magnetic circuit with slots in which an excitation winding is placed and slot wedges that ensure mechanical retention of the winding in the slots of the magnetic circuit, while protrusions in the axial direction are made in the rotor with the possibility of forming a cooling channel.

[0003] The disadvantage of this technical solution is the low filling factor of the groove with conductive material.

[0004] A rotor of a synchronous machine with an excitation winding is known [Patent US6774522B2, IPC H02K 3 / 487, published on 10.08.2004], including a rotor magnetic circuit with slots, an excitation winding placed in the slots, and slot wedges made with beveled edges of various configurations to reduce the concentration of mechanical stresses in the slot area.

[0005] The disadvantage of this technical solution is the low filling coefficient of the groove with conductive material.

[0006] A rotor of an electric machine is known [RU Patent No. 116282 U1, IPC H02K 3 / 48, published on 20.05.2012], which includes a rotor shaft, an excitation winding located in the slots of the rotor shaft, metal non-magnetic slot wedges, metal strips installed between the excitation winding and the slot wedges, wherein the slot wedge is made composite in width in the form of two opposing half-wedges, solid along the entire length of the rotor shaft slot and made at an angle along the entire length of the half-wedge on the side adjacent to the opposing half-wedge.

[0007] The disadvantage of this technical solution is the low filling factor of the groove with conductive material.

[0008] The closest to the claimed technical solution is a synchronous motor [Patent US10243436B2, IPC H02K 1 / 28, H02K 19 / 02, H02K 3 / 487, H02K 1 / 24, published on March 26, 2019], including a stator, a laminated rotor with slots, an excitation winding placed in the slots and slot wedges fixing the winding.

[0009] The disadvantage of this technical solution is the low filling factor of the groove with conductive material.

[0010] The objective of the utility model is to increase the efficiency and overload capacity of an electric machine.

[0011] The technical result of the proposed utility model is an increase in the specific power of an electric machine by increasing the filling factor of the slot with conductive material.

[0012] The technical result is achieved in that in an electric machine comprising a stator, a laminated rotor magnetic circuit with slots, an excitation winding placed in the slots of the rotor magnetic circuit, according to the utility model, the rotor magnetic circuit is axially divided by sheets, the outer diameter of which is smaller than the outer diameter of the rotor magnetic circuit packages by the amount of the radial thickness of the retaining rings installed on top of the said sheets and covering the slots of the rotor magnetic circuit, while a protective gasket is placed between the excitation winding and the retaining ring.

[0013] The essence of the utility model is explained by the drawings. Fig. 1 shows a fragment of a longitudinal section of a 3D model of an electric machine. Fig. 2 shows a 3D model of a rotor. Fig. 3 shows the design of a rotor magnetic circuit with retaining rings. Fig. 4 shows a rotor magnetic circuit sheet with a retaining ring. Fig. 5 shows a rotor sheet of a smaller diameter with a retaining ring installed.

[0014] The electric machine comprises a stator 1 (Fig. 1), a rotor 2 mounted with the possibility of rotation inside the stator 1, wherein the rotor 2 comprises a laminated magnetic circuit 3 (Fig. 2) mounted on a shaft 4, consisting of sheets of electrical steel 5 (Fig. 3), in the grooves 6 of which an excitation winding 7 (Fig. 2) is placed.

[0015] The magnetic circuit 3 of the rotor 2 is divided in the axial direction by sheets 8 of smaller diameter (Fig. 4), the outer diameter of which is smaller than the outer diameter of the magnetic circuit 3 by an amount sufficient to accommodate the retaining rings 9 (Fig. 4, Fig. 5), the outer diameter of which corresponds to the outer diameter of the magnetic circuit 3, while the retaining rings 9 overlap the grooves 6 of the rotor magnetic circuit in the radial direction.

[0016] A protective gasket 10 (Fig. 5) is placed between the excitation winding 7 (Fig. 1) of the rotor 2 and the inner surface of the retaining ring 9 (Fig. 4, Fig. 5). The protective gasket 10 can be made of an insulating material, preferably an elastic dielectric (for example, fiberglass, electrical cardboard, polymer film) with a thickness of 0.5 to 1.0 mm.

[0017] The number of sheets 8 of smaller diameter and the pitch of their axial arrangement are determined from the condition of ensuring the required mechanical rigidity of holding the excitation winding 7 to prevent its vibrations under the action of centrifugal forces, as well as a given level of reduction of electromagnetic losses in the magnetic circuit 3 of the rotor 2.

[0018] The rotor 2 design (Fig. 2), which eliminates the use of traditional slot wedges, allows for an increase in the useful cross-section of slot 6 (Fig. 3), resulting in an increased slot fill factor. Furthermore, while maintaining the same nominal machine power, the increased fill factor allows for a reduction in the current density in the conductors, further reducing the thermal load on the conductors and increasing the overload capacity of the electric machine.

[0019] In this case, the retaining rings 9 (Fig. 4), installed over the sheets 8 of smaller diameter, physically overlap the slots 6 (Fig. 3) of the laminated magnetic circuit stacks 3 in the radial direction. The inner surface of the retaining rings 9 forms a continuous retaining surface that mechanically blocks the excitation winding 7 from falling into the air gap, completely replacing traditional slot wedges.

[0020] During the rotation of the rotor 2 (Fig. 2), centrifugal forces directed radially toward the air gap of the machine act on the conductors of the excitation winding 7, located in the slots 6 (Fig. 3) of the magnetic circuit 3 (Fig. 2) of the rotor 2. Under the action of these forces, the excitation winding 7 tends to move radially and is pressed against the outer surface of the rotor 2. To prevent damage to the insulation of the excitation winding 7 during such radial movement, a protective gasket 10 (Fig. 5) is placed between the excitation winding 7 and the retaining ring 9 (Fig. 4). The said protective gasket 10 absorbs mechanical pressure and loads, excluding direct contact of the insulation of the excitation winding conductors 7 with the retaining ring 9, which protects the excitation winding 7 (Fig. 1) from abrasion, pressing through and the occurrence of interturn short circuits.

[0021] Thus, the proposed design increases the slot filling factor with conductor material by eliminating the volume of traditional slot wedges and ensures reliable wedge-free retention of the excitation winding under the action of centrifugal and vibration loads, which contributes to an increase in the specific power of the electric machine.

Claims

An electric machine comprising a stator, a laminated rotor magnetic circuit with slots, an excitation winding placed in the slots of the rotor magnetic circuit, characterized in that the rotor magnetic circuit is axially divided by sheets whose outer diameter is smaller than the outer diameter of the rotor magnetic circuit stacks by the amount of the radial thickness of retaining rings installed on top of said sheets and covering the slots of the rotor magnetic circuit, while a protective gasket is placed between the excitation winding and the retaining ring.

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