Magnetic Core Lamination Pre-Compression Method
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Solution Overview
Problem
Existing methods for building magnetic cores with laminations for rotating electrical machines are time-consuming, require manual intervention, and can damage the insulator, leading to increased energy losses due to eddy currents.
Innovation Solution
A method involving pre-compressing laminations with a separate press to achieve the desired axial length, then binding them with locking members, ensuring the magnetic core is built efficiently, automatically, and without damaging the insulator, by adding or removing laminations as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the regular construction technique (stacking and compressing laminations) is used, then the magnetic core can be built, but the production time becomes very long and manual intervention is required
Solution Approach 1:
The patent applies preliminary action by pre-compressing the lamination stack to a density higher than the final required density before binding. This pre-compression step is performed automatically by a compression device, eliminating the need for manual intervention during the compression process and significantly reducing production time while ensuring consistent magnetic core features.
2Manufacturing precision
If the lamination stack is compressed to achieve desired axial length, then the axial length precision can be controlled, but the insulator between laminations may be damaged causing increased eddy current losses
Solution Approach 1:
The patent performs pre-compression to a higher density before binding, then allows the stack to settle to the final density after binding. This two-stage compression approach achieves the desired axial length precision without excessive compression force during binding, preventing insulator damage and reducing eddy current losses.
Solution Approach 2:
The patent changes the compression parameter by applying different compression forces at different stages: high compression force during pre-compression to achieve compactness, then reduced compression force during binding to avoid insulator damage. This parameter change allows achieving axial length precision while protecting the insulator and minimizing energy losses.
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
This method reduces production time, eliminates the need for manual intervention, prevents insulator damage, and enhances energy efficiency by minimizing eddy current losses, while ensuring consistent magnetic core features.
Implementation Method 1
pre-compressing, before clamping the pack by the locking members, the group of laminations by a pre-compression press that is independent and separate from the locking members
Implementation Method 2
binding into a pack the group of laminations building the magnetic core by locking members that axially compress the group of laminations with a predetermined clamping force
Implementation Method 3
measuring an axial length of the group of laminations while the group of laminations is being compressed by the pre-compression press
Implementation Method 4
the rotating electrical machine that is normally reversible (i.e., that may operate both as electric motor by absorbing electrical power and generating mechanical driving torque, and as an electric generator by absorbing mechanical energy and generating electrical power)
Implementation Method 5
adding or removing a single lamination from the group of laminations and therefore repeating the above-described measuring cycle... does not result in damaging the insulator between the laminations with a consequential increase, even significant, of losses of power due to eddy currents
Data Source
AI summary
A method for building a magnetic core including laminations bound into packs for an electrical machine comprises steps of: stacking a group of laminations one on top of the other to build the core; binding into a pack the group building the core by locking members that axially compress the group with a predetermined clamping force; pre-compressing, before clamping the pack by the locking members, the group by a pre-compression press that is independent and separate from the locking members; measuring an axial length of the group while the group is being compressed by the pre-compression press; initially forming the group with a normally lacking number of laminations to initially have the measured length that is lower than or substantially equal to a desired length; and adding, after having completed pre-compression, an additional number of laminations to the group determined according to a difference between the desired and measured lengths.