Segment Laminated Neodymium Magnets

A laminated magnet is made by slicing a solid magnet into many thin segments and bonding them back together with a specialized adhesive. The segments are electrically insulated from one another, which suppresses electromagnetic eddy currents.

When a permanent-magnet motor runs, it generates harmonics and the magnets exhibit a skin effect; together these produce substantial eddy-current losses. The resulting temperature rise in the magnets can trigger irreversible demagnetization, threatening the motor’s safety and reliability. A laminated design mitigates this risk.

Eddy Current Simulation of Differently Segmented Permanent Magnets

• Material: N35UH magnet
• Dimensions: 20 × 160 × 5 mm
• Experiment: The magnets were tested in both non-segmented and segmented configurations across a range of excitation frequencies.

Test Results

1. Eddy-current loss decreases as the number of magnet segments increases.
2. Eddy-current loss rises with increasing excitation frequency.

Technical Requirements

1. Insulation layer thickness ≤ 0.04 mm.
2. Bond strength of the insulation layer exceeds 50 MPa at room temperature.
3. Maximum operating temperature up to 200 °C.
4. Overall geometric tolerance within 0.05 mm.
5. The individual magnet segments are mutually insulated.

Features

1. Reduces electromagnetic eddy currents.
2. Maintains magnetic properties equivalent to — or even better than — those of a solid magnet.