Single Phase Permanent Magnet Motor Notch Design
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Solution Overview
Problem
Single phase permanent magnet motors with integral magnetic laminations suffer from large cogging torque, leading to vibration, noise, and poor startup reliability due to the large slot opening.
Innovation Solution
A single phase permanent magnet motor design featuring a stator with split-type laminations and strategically positioned notches on the pole shoes, which allows the rotor to avoid the dead point position at startup, improving startup reliability by offsetting the initial rotor position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an integral magnetic lamination structure is used with large slot opening, then the manufacturing is simpler, but the cogging torque increases leading to vibration and noise
Solution Approach 1:
The integral magnetic lamination is divided into multiple segmented laminations, each with specific positioning notches. This segmentation allows the rotor to be assembled from multiple pieces that can be precisely positioned, reducing the cogging torque caused by the large slot opening while maintaining manufacturing simplicity.
Solution Approach 2:
Positioning notches are introduced asymmetrically in the segmented laminations to offset the rotor's initial position from the dead point. This asymmetric feature distribution creates a more favorable magnetic field distribution, reducing cogging torque and vibration without complicating the overall manufacturing process.
2Ease of manufacture
If an integral magnetic lamination structure is used with large slot opening, then the manufacturing is simpler, but the startup reliability deteriorates due to large cogging torque
Solution Approach 1:
The rotor is constructed from multiple segmented laminations with positioning notches that prevent the rotor from settling at dead points during startup. This segmentation enables reliable startup by ensuring the rotor starts from an optimal position, while the modular structure keeps manufacturing simple.
Solution Approach 2:
The positioning notches are pre-formed in the segmented laminations before assembly, establishing the rotor's initial position offset from dead points. This preliminary positioning action ensures reliable startup without requiring complex control systems or additional manufacturing steps.
3Reliability
If positioning notches are added to offset rotor initial position, then startup reliability improves, but the device complexity increases
Solution Approach 1:
The positioning notches are integrated into the segmented lamination structure itself, rather than being separate components. This approach improves startup reliability by offsetting the rotor position while avoiding additional device complexity, as the notches are formed as part of the manufacturing process of the segments.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design reduces cogging torque and enhances startup reliability by ensuring the rotor can start without being stuck at a dead point, leading to smoother operation and reduced vibration.
Implementation Method 1
The stator includes a stator core and windings wound around the stator core
Implementation Method 2
Single phase permanent magnet motor
Data Source
AI summary
A single phase permanent magnet motor includes a stator and a rotor. The stator includes a stator corer and windings. The stator corer includes a yoke portion and stator teeth. Each stator tooth includes a winding portion and a pole shoe connected to an end of the winding portion. Each pole shoe includes a pole face. The pole face defines a first positioning notch at a middle thereof. Each of the pole faces further defines at least one second positioning notch. Said at least one second positioning notches in one of pole shoe are located at the same side of the first positioning notch of the corresponding one pole shoe. The first and second positioning notches are configured such that an initial position of the rotor received in the space of the stator is offset from a dead point position.