Motor Winding Slot Layout for Symmetrical Automatic Wire Embedding
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Solution Overview
Problem
Existing automatic wire embedding methods for single-and double-layer windings in motors result in asymmetrical slot leakage reactance and end leakage reactance, leading to uneven no-load and short-circuit currents, increased copper loss, and higher stray losses due to three-phase winding asymmetry and extended half turn lengths.
Innovation Solution
A six-step wire embedding method for single-and double-layer windings, utilizing large-and small-slots, where each pole-phase group coil is arranged in an overlapping manner, with single-layer coils in small slots and double-layer coils in large slots, and coordinated rotations of the stator core to achieve symmetrical conductor distribution and reduced copper loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If three-phase windings are distributed in three layers at the circumference with asymmetrical positions, then automatic wire embedding can be implemented, but slot leakage reactance and end leakage reactance become asymmetrical, leading to uneven no-load current and short-circuit current
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing different slot configurations (large slots vs. small slots) and corresponding winding arrangements (double-layer vs. single-layer) to achieve symmetrical electrical characteristics. The asymmetrical physical layout is compensated through coordinated rotation of stator core and differential winding placement to ensure symmetrical reactance and current distribution.
Solution Approach 2:
The patent segments the stator slots into two types (large slots and small slots) and divides windings into two categories (double-layer and single-layer). This segmentation allows different winding configurations to be optimized for different slot types, enabling symmetrical electrical characteristics while maintaining automatic embedding capability.
2Extent of automation
If three-phase windings are distributed in three layers at the circumference, then automatic wire embedding can be implemented, but copper loss increases due to extended half turn lengths
Solution Approach 1:
The patent applies local quality principle by assigning different winding configurations to different locations. Double-layer windings with longer half-turns are placed in large slots where space is available, while single-layer windings with shorter half-turns are placed in small slots. This local optimization reduces overall copper loss while maintaining automatic embedding capability.
3Loss of energy
If single-layer coils are pulled into small stator slots and double-layer coils are pulled into large stator slots, then winding half turn length is shortened and copper loss is reduced, but complex slot insulation arrangement is required
Solution Approach 1:
The patent applies preliminary action principle by pre-arranging slot insulations in specific patterns before winding insertion. Large slots are pre-prepared with insulation configurations suitable for double-layer windings, while small slots are pre-prepared for single-layer windings. This preliminary preparation simplifies the subsequent winding insertion process despite the initial complexity of insulation arrangement.
4Manufacturing precision
If six times embedding is performed with overlapping pole-phase group coils, then symmetrical conductor distribution is achieved and current uniformity is improved, but manufacturing process complexity increases
Solution Approach 1:
The patent applies periodic action principle by performing embedding in six systematic steps with coordinated stator core rotations (0°, 60°, 120°, 180°, 240°, 300°). Each embedding step follows a repeating pattern of placing two pole-phase group coils in overlapping manner, ensuring symmetrical conductor distribution through periodic repetition of the embedding sequence.
Data Source
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AI summary
The present invention discloses an automatic wire embedding method for single-and double-layer windings based on lamination having large-and small-slots which belongs to the technical field of motor manufacturing. The method comprises: performing six times embedding to complete the wire embedding of the windings, and embedding of respective one pole-phase group coil for two phases among three phases in each time embedding, wherein the windings are single-and double-layer windings, and each pole-phase group coil consists of five coils in which a coil with a largest span is a single-layer coil and is pulled into small stator slots and the other four coils are double-layer coils and are pulled into large stator slots. The method ensures the symmetrical distribution of each phase conductor in the core slot and the end space, reduces the unevenness of no-load current and short-circuit current of the whole machine, reduces stray loss, shortens the winding half turn length, reduces the copper weight of the stator and reduces the material cost of the motor.