Li-Ion BMS

Classification of electric motors

Categorization based on drive and technology

Categorization of electromagnetic motorsbased on drive and synchronization.

Taken from the book "Li-ion Batteries and Applications".

Sync1

Drive Construction
Straight DC Varying voltage2 Magne-
tics4

Brush.5

Sinusoidal AC3 Trapezoidal Rectangular

Fully asynchronous or n.a.

Homopolar 6
Rail Gun 6, 7 		Copper
rotor

S.R.

ECM BLDC / "Servo"8 Magnet
rotor

BL

Permanent Magnet Magnet
stator

Commutator

Wound stator:
  • Self-excited:
    • Series wound, Universal9
    • Shunt wound
    • Compound wound
  • SEM/Sepex10
  • Repulsion
  • Universal9
Universal9 Universal9 Copper
rotor

Slip asynchronous

Repulsion start induction run 11
Wound rotor induction, 1ϕ or 3ϕ

S.R.

  • Induction, squirrel cage:
    • Single-phase:
      • Split-phase
      • Capacitor start
      • Capacitor run /
        Permanent Split Capacitor (PSC)
      • Capacitor start-run 12
      • Shaded pole
    • Poly-phase (e.g., 3 ϕ)
  • Linear Induction Motor/LIM7

Brushless

Synchronous

  • Hysteresis
  • Reluctance/Self-excited Synchronous:
    • Synchronous reluctance
    • Switched reluctance /
      Variable reluctance /
      Switched Reluctance Motor (SRM)
  • Variable Reluctance Stepper:
    • Unipolar
    • Bipolar
Iron
rotor
Permanent Magnet AC (PMAC) /
Permanent Magnet Synchronous Motor (PMSM) /
Brush-less Alternating Current (BLAC) 13 /
Directly Excited Synchronous Motor (DESM)
Internal Permanent Magnet (IPM) 		BLDC 14 Externally commutated
  • Permanent Magnet Stepper:
    • Unipolar
    • Bipolar
  • Hybrid Stepper
  • Coil gun inductive mass driver 7
Magnet
rotor
DC-excited synchronous Copper
rotor

S.R.

Notes:

  1. Synchronization — whether the motor rotation is synchronized with the phase of the drive:
    n.a. — not applicable for straight DC motors
    Fully asynchronous — speed is independent of the drive frequency
    Slip asynchronous — speed depends on drive frequency but is slower than it
    Synchronous — speed is locked to drive frequency
  2. Driven by time-varying voltages — Sinusoidal, trapezoidal, unipolar or bipolar rectangular
  3. Fixed sinusoidal line frequency (50/60 Hz, 1F, 3F), or variable sinusoidal frequency (1F, 3F, poly-phase)
  4. Materials — The material in the stator or rotor (rotor = slider for linear motors)
    Copper rotor — the rotor includes a winding. Some low inertia motors have no iron; just the winding. Homopolar motors have neither winding nor iron
    Magnet rotor — the rotor has a permanent magnet, no winding (hybrid steppers also have iron); the stator has iron
    Magnet stator — the stator has permanent magnets, the rotor has iron
    Copper rotor — the rotor includes a winding. Some low inertia motors have no iron; just the winding. Homopolar motors have neither winding nor iron
    Iron rotor — the rotor is magnetic metal, not permanently magnetized; it has no winding
  5. Brushing — electrical connection to the rotor
    Brushless (B.L.) — no brushes
    Slip ring (S.R.) — brushes and slip ring
    Commutator — brushes and commutator
  6. True DC motor; requires no commutation
  7. Linear motor
  8. ECM —Electronic Commutator Motor: transistors/ICs (contrast with Externally commutated BLDC - external electronics)
    BLDC — Brush Less Direct Current
    Inside the motor, an electronic commutator converts the applied DC voltage to a trapezoidal wave that is in sync with the rotation of the rotor, to power specific windings
    "servo" is a misnomer, derived from "servo-loop", which is something completely different
  9. Universal motor — appears twice, as it may be driven by AC or DC; it's a series wound motor
  10. Sepex — Separately excited: the field winding is powered by a separate source; the field is independent of armature current
  11. Starts asynchronous, runs slip asynchronous
  12. Two capacitors
  13. Requires a sinusoidal waveform (contrast with BLDC motor)
  14. Brushless DC; requires a trapezoidal waveform (contrast with BLAC motor - sinusoidal; contrast with ECM BLDC - internal electronics)

This table presents the same information in list form.
# Name Drive Sync Magnetics Brushing
1BLDC, Externally commutatedTrapezoidalSynchronousMagnet rotorBrushless
2BLDC, Internally commutated, Electronic Commutator MotorStraight DCn.a.Magnet rotorBrushless
3Brushless AC (BLAC)SinusoidalSynchronousMagnet rotorBrushless
4Capacitor run, single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
5Capacitor start-run, single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
6Capacitor start, single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
7Coil gun inductive mass driver (linear)RectangularSynchronousMagnet sliderBrushless
8Compound wound, wound stator, self excitedStraight DCn.a.Copper rotorCommutator
9DC-excited synchronousSinusoidalSynchronousCopper rotorSlip ring
10Directly Excited Synchronous Motor (DESM)SinusoidalSynchronousMagnet rotorBrushless
11ECM BLDC, Electronic Commutator Motor Brushless DCStraight DCn.a.Magnet rotorBrushless
12Externally commutated BLDCTrapezoidalSynchronousMagnet rotorBrushless
13HomopolarStraight DCn.a.Copper rotor Slip ring
14Hybrid StepperRectangularSynchronousMagnet rotorBrushless
15HysteresisSinusoidalSynchronousIron rotorBrushless
16Induction (squirrel cage), poly-phaseSinusoidalSlipCopper rotorBrushless
17Internal Permanent Magnet AC (IPM)SinusoidalSynchronousMagnet rotorBrushless
18Linear induction motor , LIM (linear)SinusoidalSlipCopper sliderBrushless
19Permanent Magnet Synchronous Motor (PMSM)SinusoidalSynchronousMagnet rotorBrushless
20Permanent Magnet (PM)Straight DCn.a.Magnet statorCommutator
21Permanent Magnet AC (PMAC)SinusoidalSynchronousMagnet rotorBrushless
22Permanent Magnet Stepper, unipolar or bipolarRectangularSynchronousMagnet rotorBrushless
23Permanent Split Capacitor (PSC), single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
24Rail Gun (linear)Straight DCn.a.Copper slider Slip ring
25ReluctanceSinusoidalSynchronousIron rotorBrushless
26RepulsionSinusoidalAsyncCopper rotorCommutator
27Repulsion start induction runSinusoidalAsync / SlipCopper rotorCommutator
28Self-excited SynchronousSinusoidalSynchronousIron rotorBrushless
29Separately Excited Motor, SEM, Sepex, wound statorStraight DCn.a.Copper rotorCommutator
30Series wound, wound stator, self excitedStraight DCn.a.Copper rotorCommutator
31"Servo"Straight DCn.a.Magnet rotorBrushless
32Shaded pole, single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
33Shunt wound, wound stator, self excitedStraight DCn.a.Copper rotorCommutator
34Split-phase, single phase induction (squirrel cage)SinusoidalSlipCopper rotorBrushless
35Squirrel cage - see individual typesSinusoidalSlipCopper rotorSlip ring
36Switched Reluctance Motor (SRM)SinusoidalSynchronousIron rotorBrushless
37Synchronous reluctanceSinusoidalSynchronousIron rotorBrushless
38Universal - wound stator, self excitedAnyAsyncCopper rotorCommutator
39Variable reluctanceSinusoidalSynchronousIron rotorBrushless
40Variable Reluctance Stepper, unipolar or bipolarRectangularSynchronousIron rotorBrushless
41Wound rotor inductionSinusoidalSlipCopper rotorSlip ring
42Wound stator - see individual typesStraight DCn.a.Copper rotorCommutator

© 2008~2025 Davide Andrea. All rights reserved, except where noted by CC mark. Page published on Feb 09 2023. Graphic design by morninglori
 

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