Brushed DC Motors and Brushless Motors

Brushed DC Motors and Brushless Motors
Comparison of Brushed and Brushless Motors
Item Brushed DC motor Brushless motor
Rotor structure Coil Permanent magnet
Stator structure Permanent magnet (Note 1) Coil
Control mechanism Brush and commutator (inside motor) Inverter circuit
Detection of rotor position Not required Required (controlled by rotor position)
Starting Easy Control required (acceleration)
Variable speed Easy (voltage proportional) Control required (voltage + frequency proportional)
Forward/Reverse Easy (the polarity to reverse) Control required (the control order to reverse)
Controllability - Change the control
Durability Low (due to brush wear) High (no brush)
Sound, vibration, noise - Quiet, low vibration, low noise
Efficiency - Good (sine wave drive is possible)
Price Relatively cheap A little expensive when including the control circuit

Note 1) Some stator structures have various types.

Chapter 2 Driving Principle of a Brushless Motor

Driving Principle of a Motor (1)
Driving Principle of a Motor (2)
Sequence of a Brushed DC Motor
Sequence of a Brushless Motor
Relation Between a Pole, a Phase, and a Slot