Glossary

Back EMF is the voltage generated when a permanent magnet motor is rotated. This voltage is proportional to motor speed and is present regardless of whether the motor winding(s) are energized or de-energized.

Breakaway torque is the torque required to start a machine in motion. Almost always greater than the running torque.

Brushed motor is a servo motor in which the commutation of the current is accomplished by the use of mechanical brushes rather than through electronic commutation. The brushes remain in contact with the commutator, therefore current is constantly flowing to the armature coils. The main advantages of a brushed motor are high starting torque and low cost, these features make them common in industrial environments.

A Brushless motor is a servo motor in which the commutation of the current is accomplished electronically rather than through the use of mechanical brushes and a commutator. In a brushless motor, the windings are on the stator and the magnetic field is provided by permanent magnets in the armature. This results in higher motor efficiency,  increased heat dissipation, longer lifespan, and quieter operation.

Bus is one or more conductors used as a path over which information is sent from one of many sources to one of many destinations.