NdFeB Magnets in EV Traction Motors: Grades, Specifications, and What Engineers Need to Know

Permanent-magnet synchronous motors are one traction architecture alongside electrically excited and induction machines. BMW’s iX xDrive50 documentation from 2021 describes electrically excited synchronous motors with electrical rotor excitation rather than fixed permanent magnets. It is therefore incorrect to claim that every major EV motor uses NdFeB or to use that model as a magnet-segmentation example.

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. Grades up to N52SH can be made without a Chinese export licence, so we offer those first; UH and EH grades need a licence, applied for per order. 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.

The reported N45H magnetic comparison and the separate historical 50H Dy-reduction example have different scopes. See the GBD evidence and limitations. Finished-part savings require a quotation and qualification of the proposed route.

For an interior permanent-magnet design, show the pocket geometry, magnet orientation, bridges, clearances and assembly method. The rotor can produce both magnetic and reluctance torque. Evaluate the full motor design instead of assigning a fixed efficiency or torque-density advantage to the magnet alone. Agree the magnetic, dimensional, assembly and conditioning tests and their acceptance limits. 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.