Li-Ion BMS

Classification of electric motors

Categorization based on drive and technology

This categorization of electric motors, classifies common rotary and linear electromagnetic motors according to type of drive (AC / DC) and other characteristics.

Bold motors are typically used in EVs. Links go to the section for their drivers.
Drive Sinusoidal AC ✔ Line frequency (1Φ, 3Φ, polyΦ)
Variable frequency
✔ Line frequency (1Φ)
Switched DC
Straight DC
Commutation External
No commutation inside the motor to generate a rotating magnetic field; an external device must generate the time-varying voltages to drive the motor.
(Wound rotor induction motors are brushed, but not to generate the rotating magnetic field.)
Internal
Inside the motor a commutator (mechanical or electronic) converts the DC voltage (at the 2 motor terminals) to an AC wave that is in synch with the rotation of the rotor, to power specific windings.
None
True DC motor, requires no commutation.
Rotary
motors
Iron
rotor
The rotor is magnetic metal, not permanently magnetized; it has no winding
Brushless
Synchronous
  • Hysteresis
  • Reluctance / Self-excited Synchronous Motor
    • Synchronous reluctance
    • Switched reluctance / variable reluctance / SRM
  • Variable Reluctance Stepper
    • Unipolar
    • Bipolar
Magnet
rotor
(+ iron)
The rotor has a permanent magnet, no winding.
(Hybrid steppers also have iron.)
Brushless Synchronous
(PMAC: Permanent magnet AC)
  • PMSM (Permanent Magnet Synchronous Motor) / BLAC (Brush Less Alternating Current) / Directly Excited Synchronous Motor / IPM (Internal Permanent Magnet)
  • External controller BLDC (Brush-less Direct Current)
  • Permanent Magnet Stepper
    • Unipolar
    • Bipolar
  • Hybrid Stepper
Brushless (electronic commutator: transitors / ICs)
  • Integral controller BLDC
    (Brush Less Direct Current)
Magnet
stator
(+ iron)
Stator has permanent magnets
Brushed commutator
  • PM
    (Permanent Magnet)
Copper
rotor
(+ iron)
The rotor includes a winding. (Some low inertia motors have no iron; just the winding) (Homopolar motors have neither winding nor iron)
Brushless
Slip asynchronous
  • Induction, squirrel cage
    • Single phase
      • Split phase
      • Capacitor start
      • Capacitor run / PSC (Permanent Split Capacitor)
      • Capacitor start-run (2 capacitor)
      • Shaded pole
    • Polyphase (e.g.: 3 ph.)
Brushed slip ring
Synchronous
  • Induction, synchronous, wound rotor
Brushed commutator
Slip asynchronous
  • Wound rotor
    • Repulsion
    • Repulsion start
    • Repulsion induction
Brushed
commutator
  • Universal
Brushed commutator
Brushed
  • Homopolar
Linear motors
Brushless
Synchronous
  • Coil gun inductive mass driver
Brushless
Slip asynchronous
  • LIM (Linear Induction Motor)
Brushed
  • Rail gun mass driver

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