Motor Type Selection
GearheadGear MotorBrushless DC (BLDC) MotorMotorsDC MotorBrushed DC motor
Parameters that define a motor type are the mechanical output power, the shaft bearing system, the commutation system used, and the possible combinations with gear-heads and sensors. The most important criteria include the speed and torque requirements, and the commutation system.
Some of the formulas used in this article use subscripts that need to be explained. The variables on the motor shaft (output) are identified with the subscripts Mot. For example, nMot stands for the required motor speed. Parameters that describe the characteristics of the motor have no special additional subscript. For example, no stands for the no-load speed of the motor.
We’ll discuss speed and torque requirements first. The maximum speed that occurs on the motor shaft nmaxMot should be below the maximum permissible speed of the motor nmax, or nmaxMot < nmax.
As a rule, expected useful life decreases as motor speed increases because of the greater load on the bearings and the higher mechanical wear of the brush system on DC motors. Noise generation...