Rotor of motor
By designing the rotor groove of the motor as a positive inverted trapezoidal structure, combined with the flow guide strip and the bus ring, the problems of excessive starting current and insufficient mechanical strength of the high-power motor are solved, and the starting current and the mechanical strength are reduced, while maintaining the efficient operation of the motor.
Patent Information
- Application Number
- CN202422372567.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-28
- Publication Date
- 2025-08-15
- Estimated Expiration
- 2034-09-28
AI Technical Summary
The starting current is too high when starting a high-power motor, resulting in difficulty in starting and a drop in the grid voltage. At the same time, the prior art increases the rotor diameter and material consumption.
The upper half of the groove body is in a regular trapezoid and the lower half is in an inverted trapezoid. The guide bar and the convergence ring form an integral part, enhancing the parallelism of the lower half of the tooth body, improving mechanical strength, and concentrating the current at startup through the skin effect to reduce the starting current.
Without increasing material consumption, the starting current is reduced, the mechanical strength of the core is improved, and the operation efficiency of the motor is ensured.
Smart Images
Figure CN223230948U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a rotor of an electric motor, which can reduce the starting current of the electric motor. Background Art
[0002] When a high-power motor starts, its starting current typically reaches 4-7 times the rated current. Such a high starting current can make the motor difficult to start and cause a sharp drop in the grid voltage. To reduce the motor's starting current, the rotor uses trapezoidal slots with current guide bars connected to slip rings at both ends. Adjacent trapezoidal slots form tooth-shaped bodies. Because the slots have a wide bottom and a narrow mouth, the root of the tooth-shaped body is narrow and the head of the tooth-shaped body is wide. This results in a higher magnetic flux density at the root of the core teeth and reduces the core's mechanical strength. To reduce the magnetic flux density at the root of the teeth and the mechanical strength of the core, the rotor diameter needs to be increased, which increases the material consumption of the motor. Utility Model Content
[0003] In order to solve the above problems, the present invention proposes a rotor for an electric motor, which can reduce the starting current of the electric motor and improve the mechanical strength of the iron core on the basis of increasing the rotor diameter.
[0004] The technical solution to the technical problem solved by the present invention is a rotor of an electric motor, which includes an iron core composed of stacked silicon steel sheets 6, a guide bar 3, and a slip ring 2. A plurality of slots 5 are symmetrically arranged on the silicon steel sheet, and a tooth-shaped body 4 is formed between adjacent slots. The guide bar passes through the slot, and the slip ring is located on both sides of the silicon steel sheet. The two ends of the guide bar and the slip ring are formed into a whole by casting. The upper half of the slot is a regular trapezoid, and the lower half of the slot is an inverted trapezoid.
[0005] Compared with the prior art, the beneficial effect of the present invention is that the two sides of the lower half of the tooth-shaped body 4 of the iron core can be parallel to each other, reducing the magnetic density at the tooth root; under the condition of the same rotor diameter, the width of the tooth root of the present invention is increased, which is beneficial to improving the mechanical strength of the iron core.
[0006] The upper half of the slot body is a right trapezoid with a small diversion cross-sectional area. When the motor starts, the current in the guide bar is relatively concentrated in the right trapezoid part due to the skin effect, which significantly increases the impedance of the rotor and effectively suppresses the starting current.
[0007] When the motor runs at rated speed, the skin effect disappears, the current density in the guide bar is uniform, the guide cross-sectional area of the inverted trapezoidal part of the guide bar is large, the impedance of the rotor is low, the increase of rotor loss is avoided, and the efficiency of the motor is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 It is a structural schematic diagram of the utility model.
[0009] Figure 2 for Figure 1 Right view of .
[0010] The symbols in the accompanying drawings respectively represent: 1-rotating shaft, 2-collecting ring, 3-guide bar, 4-toothed body, 5-trough body, 6-silicon steel sheet. DETAILED DESCRIPTION
[0011] A motor rotor includes an iron core composed of stacked silicon steel sheets 6, a guide bar 3, and a slip ring 2. A rotating shaft 1 is fixedly inserted into the iron core. Several slots 5 are symmetrically arranged on the silicon steel sheets. The guide bars pass through the slots. The slip rings are located on both sides of the silicon steel sheets. The two ends of the guide bar and the slip ring are formed into an integral whole by casting.
[0012] The upper half of the trough is a regular trapezoid, while the lower half is an inverted trapezoid. The small end of the regular trapezoid in the upper half is located at the outer edge of the silicon steel sheet, and the junction of the regular and inverted trapezoids forms the large end. The small end of the inverted trapezoid in the lower half of the trough faces the center of the silicon steel sheet. Adjacent troughs form a tooth-shaped body 4. By selecting the gradient of the lower half of the trough, the two sides of the lower half of the tooth-shaped body 4 can be made parallel to each other. This increases the width of the tooth root, which helps reduce the magnetic flux density at the tooth root and improve the strength of the rotor core. At the same time, the length of the lower half of the trough can be appropriately increased, thereby increasing the cross-sectional area of the guide bar, which helps reduce the resistance of the guide bar and reduce rotor losses during motor operation. The length of the lower half of the trough is twice that of the upper half.
[0013] In order to further reduce the starting current, the width of the large end of the positive trapezoid is smaller than that of the large end of the inverted trapezoid, and the width of the large end of the positive trapezoid is 1 / 3 of the width of the large end of the inverted trapezoid.
[0014] Its working principle is that when the motor starts, the current in the guide bar is relatively concentrated in the positive trapezoidal part due to the skin effect, which significantly increases the impedance of the rotor and effectively suppresses the starting current.
[0015] When the motor runs at rated speed, the skin effect disappears, the current density in the guide bar is uniform, the guide cross-sectional area of the inverted trapezoidal part of the guide bar is large, the impedance of the rotor is low, the increase of rotor loss is avoided, and the motor efficiency is guaranteed.
Claims
1. A rotor of an electric motor, comprising an iron core composed of stacked silicon steel sheets (6), a guide bar (3), and a slip ring (2), wherein a plurality of slots (5) are symmetrically arranged on the silicon steel sheet, and tooth-shaped bodies (4) are formed between adjacent slots, the guide bar passes through the slot, and the slip ring is located on both sides of the silicon steel sheet, and the two ends of the guide bar and the slip ring are formed into an integral body by casting, wherein: The upper half of the trough body is a regular trapezoid, and the lower half of the trough body is an inverted trapezoid.
2. The rotor of an electric motor according to claim 1, wherein: The two sides of the lower half of the tooth-shaped body (4) are parallel to each other.
3. The rotor of an electric motor according to claim 1, wherein: The length of the lower half of the trough body is twice that of the upper half of the trough body.
4. The rotor of an electric motor according to claim 1, wherein: The width of the large end of the regular trapezoid is 1 / 3 of the width of the large end of the inverted trapezoid.