A permanent Auto Chain magnet motor is a kind of brushless electric motor that uses long term magnets rather than winding in the field.
This type 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 better than induction engine or motors with field windings for several high-efficiency applications such as electric powered vehicles. Tesla’s Chief Motor Designer was quoted discussing these advantages, saying: “It’s well known that permanent magnet devices have the benefit of pre-excitation from the magnets, 
and therefore you involve some efficiency benefit for that. Induction devices have ideal flux regulation and for that reason you can improve your efficiency. Both make sense for variable-velocity drive single-gear tranny as the drive products of the cars. Therefore, as you know, our Model 3 includes a long term magnet machine now. The reason being for the specification of the overall performance and efficiency, the long term magnet machine better solved our price minimization function, and it was optimal for the number and performance target. Quantitatively, the difference is usually what drives the future of the machine, and it’s a trade-off between motor cost, range and battery cost that is determining which technology will be used 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 some motors, these magnets are mounted with adhesive on the surface of the rotor core such that the magnetic field can be radially directed across the surroundings gap. In other styles, the magnets are inset into the rotor core surface or inserted in slot machine games just below the surface. Another form of permanent-magnet engine provides circumferentially directed magnets placed in radial slots that provide magnetic flux to iron poles, which in turn create a radial field in the air flow 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 controlled source. Such drives are capable of precise speed and position control. Because of the lack of power losses in the rotor, as compared with induction engine drives, they are also highly efficient.
Permanent-magnet motors could be made to operate at synchronous speed from a supply of continuous voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is placed in slot machine games in the rotor surface to provide starting capability. This kind of a motor will not, however, have method of controlling the stator power factor.