Arc & Segment shape

Neodymium arc shape magnets used in Motor Applications

Neodymium magnets are also used in electric car motor applications. From the motor that spins a DVD disc to the wheels of a hybrid car, neodymium magnets are used throughout the vehicle. The decision between Samarium Cobalt or Neodymium as a vehicle magnet is usually based on either
operating temperature and/or corrosion resistance.

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Operating temperature:

A low coercivity grade Neodymium magnet may begin to lose strength if heated above 176°F (80°C). High coercivity grade Neodymium Magnets have been developed to function at temperatures up to 428°F (220°C) with little irreversible loss. The need for low temperature coefficient in neodymium magnet applications has triggered several grades to be developed to meet specific operating requirements. Please refer to our chart of magnetic properties to compare the characteristics of each grade.

Corrosion:

Neodymium magnets are vulnerable to corrosion, especially along grain boundaries of a sintered magnet. This type of corrosion can cause serious deterioration, including crumbling of a magnet into a powder of small magnetic particles. This vulnerability is addressed by adding a protective coating to prevent exposure to the atmosphere. Nickel plating or two-layered copper-nickel plating are the standard methods, although plating with other metals or polymer and lacquer protective coatings are also available.

An electromagnetic coil is attracted to a permanent magnet within the magnetic motor assembly, and this attraction is what causes the motor to rotate. When the source of electrical power is removed, the wire loses its magnetic qualities and the motor stops. In this way, the rotation and motion of permanent magnet motors can be managed by a motor driver that controls when and for how long electricity (and, by extension, the electromagnet) allows for rotation of the motor.