Motor Magnets - Arcs, Squares, Rectangles And Radial Rings

  •   Motor design is a true balance of all materials: magnets, stators, laminations, wire size & insulations, etc. Choosing the best magnet begins with knowing your overall objectives with torque, RPM, and start-up load.

      The three (3) most commonly used permanent magnets used in motors are Neodymium Magnets, Samarium Cobalt (SmCo) Magnets, and Ferrite / Ceramic Magnets. Below is a summary of each magnet material, and an overview of their advantages and disadvantages.

      Ring Neodymium Magnet

      Neodymium magnets are the strongest magnets on the market and give the most magnetic field in a motor circuit. They come in many material variations, and selection of the appropriate material will depend upon such items as temperature requirements, operating environment, and field strength. Below is a list of advantages and disadvantages for neodymium magnets:

      Neodymium Magnets

      Advantages

      High Induction (Br). Grades 30-55

      Good resistance to demagnetization (Hci)

      High Flux density / sq. cm (MGOe)

      Correctly selected material will last indefinitely

      Can reduce size / weight / size of rotor & stator

      Large selection of material grades

      Disadvantages

      Can oxidize if not coated

      Lower working temp than some other materials

      Summary

      Neodymium Magnets will work well in an application that requires high stability, high induction over a lower operating temperature.

      Samarium Cobalt Magnets

      These magnets are the strongest magnets on the market after Neodymium Magnets. They come in several material variations, better known as SmCo 1-5, or SmCo 2-17. Below is a list of advantages and disadvantages:

      Samarium Cobalt Magnets

      Advantages

      High Induction (Br). Grades 16-32

      Great resistance to demagnetization (Hci), up to 350C

      Excellent resistance to oxidation without coating

      Disadvantages

      High cost

      More brittle, easier to chip & break

      Summary

      Samarium Cobalt magnets will work well in a high temperature applications that requires a large resistance to demagnetization

      Ferrite / Ceramic Magnets

      These magnets are the most widely used in motors due to lower cost. But with the low cost comes other trade offs. Below is a list of advantages and disadvantages:

      Ferrite / Ceramic Magnets

      Advantages

      Low cost

      Great resistance to oxidation

      Large abundance of raw materials

      Disadvantages

      Low Induction (Br), Grades 1-10

      Usually requires a mold

      May deteriorate in magnetic field over time.

      Lower resistance to demagnetization

      Summary

      Ceramic magnets will work well in an application where greater concern is given over the size & weight requirements.

      Picking the Correct Magnet

      Each motor design is very different and working with an experienced magnet professional is important. The correct engineering partner can work through all of the design considerations, prototypes, changes, and manufacturability with you. Magnets can be made in many shapes and virtually any size, so getting the correct size.

        Do not hesitate to contact us,as an professional SmCo Ring Magnets manufacturer, We will offer the best service for every customer.