A permanent magnet motor is a type of brushless electric electric motor that uses long lasting magnets instead of winding in the field.

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

Permanent magnet motors are better than induction motor or motors with field windings for several high-efficiency applications such as for example electric vehicles. Tesla’s Chief Electric motor Designer was quoted talking about these advantages, stating: “It’s well known that permanent magnet machines have the advantage of pre-excitation from the magnets, and therefore you have some efficiency advantage for that. Induction machines have ideal flux regulation and therefore you can optimize your efficiency. Both make sense for variable-acceleration drive single-gear transmitting as the drive units of the cars. Therefore, as you know, our Model 3 includes a permanent magnet machine now. It is because for the specification of the functionality and efficiency, the long lasting magnet machine better solved our price minimization function, and it was optimal for the range and performance target. Quantitatively, the difference is usually what drives the future of the machine, and it’s a trade-off between motor price, range and battery cost that is identifying which technology will be used in the future.
The magnetic field for a synchronous machine could be provided by using permanent magnets made of agricultural Chain neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In some motors, these magnets are mounted with adhesive on the top of rotor core such that the magnetic field can be radially directed across the air flow gap. In other designs, the magnets are inset in to the rotor core surface or inserted in slots 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 create a radial field in the surroundings gap.

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

Permanent-magnet motors could be designed to operate at synchronous swiftness from a way to obtain continuous voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is placed in slots in the rotor surface to supply starting capability. This kind of a motor does not, however, have means of controlling the stator power element.