Brushed direct current electric motor with salient pole rotor

A brush direct current motor, comprising:

• a stator comprising a plurality of teeth and a plurality of coils wound around the teeth and corresponding to N phases;
• a rotor coupling the stator, the rotor comprising a shaft, a rotor core fixed to the shaft and P salient poles made of magnetically conductive material and protruding from the shaft toward the teeth;
• a first brush;
• N second brushes;
• and
• a commutator fixed to the shaft;
• wherein the commutator comprises a first conductive ring, P first bars extending from the first conductive ring;
• wherein the first brush is arranged to be electrically connected to a first terminal of a direct current power source and is arranged to make continuous sliding electrical contact with the first conductive ring, and the second brushes are arranged to make sliding electrical contact with the first bars;
• and
• wherein one end of each phase is respectively connected to one of the N second brushes, and the other ends of each phase are arranged to be electrically connected to a second terminal of the direct current power source,
• wherein the sum of the central angle “A” corresponding to the first bar and the central angle “B” corresponding to the second brush is not less than the commutation angle “β”, where β=|360/T−360/M|, “T” represents the number of stator teeth, and “M” represents the number of rotor poles.