Permanent magnet motor

A permanent magnet engine is a kind of brushless electric motor that uses long lasting magnets rather than 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 models 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 certain high-efficiency applications such as for example electrical vehicles. Tesla's Chief Engine Designer was quoted talking about these advantages, stating: “It's popular that permanent magnet machines have the benefit of pre-excitation from the magnets, and for that reason you involve some efficiency advantage for that. Induction machines have ideal flux regulation and therefore you can improve 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 has a long term magnet machine now. This is because for the specification of the overall performance and efficiency, the permanent magnet machine better solved our cost minimization function, and it was optimal for the number and performance target. Quantitatively, the difference is certainly what drives the future of the machine, and it's a trade-off between motor cost, 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 long term magnets made of neodymium-boron-iron, samarium-cobalt, or ferrite on the rotor. In some motors, these magnets are installed with adhesive on the surface of the rotor core such that the magnetic field is definitely radially directed over the air flow gap. In other designs, the magnets are inset into the rotor core surface area or inserted in slot machines just underneath the surface. Another form of permanent-magnet engine has circumferentially directed magnets placed in radial slots that provide magnetic flux to iron poles, which in turn setup a radial field in the air flow gap.

The main application for permanent-magnet motors is in variable-speed drives where the stator comes from a variable-frequency, variable-voltage, electronically Leaf Chain managed source. Such drives are capable of precise speed and position control. Due to the absence of power losses in the rotor, in comparison with induction motor drives, they are also highly efficient.

Permanent-magnet motors could be made to operate at synchronous quickness from a supply of constant voltage and frequency. The magnets are embedded in the rotor iron, and a damper winding is usually placed in slot machine games in the rotor surface to provide starting capability. This kind of a motor does not, however, have means of managing the stator power element.