A permanent magnet engine is a type of brushless electric engine that uses long term 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] Other Tesla models use traditional induction motors motors.[3] Front motors in all-wheel drive Model 3 Teslas are also induction motors.
Long lasting magnet motors are more efficient than induction motor or motors with field windings for certain high-efficiency applications such as electrical vehicles. Tesla’s Chief Motor Designer was quoted talking about these advantages, saying: “It’s popular that permanent magnet devices have the benefit of pre-excitation from the magnets, and therefore you involve some efficiency benefit for that. Induction machines have ideal flux regulation and for that Leaf Chain reason you can optimize your efficiency. Both seem sensible for variable-quickness drive single-gear transmitting as the drive devices of the cars. Therefore, you may already know, our Model 3 has a long lasting magnet 
machine now. It is because for the specification of the functionality and efficiency, the permanent magnet machine better solved our price minimization function, and it was optimal for the range and performance target. Quantitatively, the difference can be what drives the future of the device, and it’s a trade-off between motor price, range and battery price that is identifying which technology will be utilized in the future.
The magnetic field for a synchronous machine could be provided by using permanent magnets manufactured from neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In a few motors, these magnets are installed with adhesive on the top of rotor core such that the magnetic field is usually radially directed over the surroundings gap. In other styles, the magnets are inset in to the rotor core surface or inserted in slots just underneath the surface. Another type of permanent-magnet engine offers circumferentially directed magnets placed in radial slots offering magnetic flux to iron poles, which in turn setup a radial field in the atmosphere gap.
The primary 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. Because of the lack of power losses in the rotor, as compared with induction motor drives, also, they are highly efficient.
Permanent-magnet motors could be designed to operate at synchronous swiftness from a way to obtain constant voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding can be placed in slot machine games in the rotor surface area to supply starting capability. Such a motor does not, however, have method of managing the stator power factor.