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A permanent magnet motor is a type of brushless electric electric motor that uses permanent magnets rather than winding in the field.

This kind of motor can be used in the Chevy Bolt[1], the Chevy Volt, and the Tesla Model 3.[2] Various other Tesla models use traditional induction motors motors.[3] Front motors in all-wheel drive Model 3 Teslas are also induction motors.

Long term magnet motors are more efficient than induction motor or motors with field windings for several high-efficiency applications such as electric powered vehicles. Tesla’s Chief Engine Designer was quoted discussing these advantages, saying: “It’s popular that permanent magnet machines have the benefit of pre-excitation from the magnets, and for that reason you have some efficiency benefit for that. Induction machines have ideal flux regulation and for that reason you can enhance your efficiency. Both seem sensible for variable-quickness drive single-gear tranny as the drive products of the cars. So, you may already know, our Model 3 has a long term magnet machine now. This is because for the specification of the overall performance and efficiency, the permanent magnet machine Auto Chain better solved our price minimization function, and it was optimal for the number and performance target. Quantitatively, the difference can be what drives the continuing future of the device, and it’s a trade-off between motor price, range and battery cost that is identifying which technology will be utilized in the future.
The magnetic field for a synchronous machine could be provided by using long lasting magnets made of neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In some motors, these magnets are installed with adhesive on the top of rotor core such that the magnetic field is definitely radially directed over the air gap. In other styles, the magnets are inset into the rotor core surface or inserted in slot machines just below the surface. Another type of permanent-magnet motor has circumferentially directed magnets placed in radial slots offering magnetic flux to iron poles, which in turn set up a radial field in the atmosphere gap.

The main application for permanent-magnet motors is in variable-speed drives where the stator is supplied from a variable-frequency, variable-voltage, electronically managed source. Such drives are capable of precise speed and placement control. Due to the lack of power losses in the rotor, as compared with induction electric motor drives, also, they are highly efficient.

Permanent-magnet motors can be made to operate at synchronous swiftness from a supply of constant voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is usually placed in slots in the rotor surface area to supply starting capability. Such a motor will not, however, have means of managing the stator power factor.