In This Article
Key Takeaways
- ◆Diameter and pole count require confirmation as a pair.
- ◆Distinguish the magnet’s material orientation from the later magnetization pattern.
- ◆An OD scan is not a motor back-EMF or position-accuracy test.
- ◆Mainrich’s sintered NdFeB range is N30 to N56, with no AH grades. The top grade depends on the temperature series: N56, N54M, N52H, N52SH, N50UH and N45EH. Confirm the grade, suffix, geometry and production route for each drawing. This summary does not offer every combination; grades outside it in educational examples are not Mainrich supply offers.
- ◆Grade suffixes and F/N/D series labels do not establish composition or export clearance. Classify the actual item and transaction with the exporter, including the parties, end use and route. See the export-control guide.
Confirm the micro-ring route
Send the outside and inside diameters, wall, length and pole count on one drawing. Micro-ring examples do not extend the separate radial-ring production window. Confirm dimensions and fixture capability for the actual route before quoting.
Specify the magnetic field
In a slotless or coreless design, evaluate the actual winding and magnetic circuit. Define the target field and harmonics at the working location. The ring shape alone does not establish sinusoidal back-EMF or zero torque ripple.
Match the pole pattern to the drive
Electrical frequency equals pole pairs times mechanical revolutions per second. Confirm that the inverter, winding and magnetizing fixture support the chosen pattern. Increasing pole count changes the pole pitch and transition regions; a generic diameter threshold does not settle the design.
Check sensing requirements
If the magnet also feeds a position sensor, define the sensor location, angle reference and field-direction limits. Test the assembled sensing system. A surface-field trace does not establish encoder accuracy or a field-free bore.
Select the material
Select the grade using the actual hot demagnetization curves, the magnetic circuit working point and the worst opposing field. A suffix is a nominal material class, not a guaranteed motor temperature limit or a chemical recipe. Mainrich’s sintered NdFeB range is N30 to N56, with no AH grades. The top grade depends on the temperature series: N56, N54M, N52H, N52SH, N50UH and N45EH.
Confirm the grade, suffix, geometry and production route for each drawing. This summary does not offer every combination; grades outside it in educational examples are not Mainrich supply offers. Grade suffixes and F/N/D series labels do not establish composition or export clearance. Classify the actual item and transaction with the exporter, including the parties, end use and route. See the export-control guide.
Qualify and order
Agree dimensional and magnetic measurements with their conditions, traceability and sampling. Check the current certificate for the actual manufacturing entity, address and activity. Agree PPAP level and required reports for the order; a network relationship does not certify every plant or assembly.
Agree tooling, sample quantity, inspection and production milestones in the quotation. Export release depends on any required authorization. No standard prototype quantity or fixed delivery interval is promised here.
Frequently Asked Questions
How small can a multipole ring be?
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Confirm the complete dimensions and pole pattern with the intended route. No universal minimum diameter or pole-count inventory is offered here.
What grade is available?
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Mainrich’s sintered NdFeB range is N30 to N56, with no AH grades. The top grade depends on the temperature series: N56, N54M, N52H, N52SH, N50UH and N45EH. Confirm the grade, suffix, geometry and production route for each drawing. This summary does not offer every combination; grades outside it in educational examples are not Mainrich supply offers.
How is F-Series export classification established?
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Grade suffixes and F/N/D series labels do not establish composition or export clearance. Classify the actual item and transaction with the exporter, including the parties, end use and route. See the export-control guide.
What should a field test specify?
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In a slotless or coreless design, evaluate the actual winding and magnetic circuit. Define the target field and harmonics at the working location. The ring shape alone does not establish sinusoidal back-EMF or zero torque ripple. If the magnet also feeds a position sensor, define the sensor location, angle reference and field-direction limits. Test the assembled sensing system. A surface-field trace does not establish encoder accuracy or a field-free bore.
How long does qualification take?
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Agree tooling, sample quantity, inspection and production milestones in the quotation. Export release depends on any required authorization. No standard prototype quantity or fixed delivery interval is promised here.
Send the micro-ring drawing, pole pattern, thermal duty and measurement requirement for review.
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