What are the advantages & disadvantages of different types of motors?

DC Motors:

  1. Brushed DC Motor
  2. Brushless DC Motor

Motor Categories:

  1. Stepper Motor
  2. Servo Motor
  3. Linear Motor

Electric motors are machines that convert electrical energy—from either stored power or a direct electrical connection—into mechanical energy through the production of rotational force. The two major types of electric motors are:

  • AC motors, which are powered by alternating current
  • DC motors, which are powered by direct current

Both AC and DC motors use electrical current to produce rotating magnetic fields that, in turn, generate rotational mechanical force in the armature—located on the rotor or stator—around the shaft.

See the below image for the advantages of AC vs. DC motors:

Looking beyond the two broad categories, this is where there are sub-sets of types of AC & DC Motors.

  1. Brushed DC Motors: The brushes and commutator inside a brushed motor mechanically commutate the motor windings and it continues rotation as long as its power supply is connected. Brushed motors are easy to control, but require periodic maintenance and replacement of brushes, and therefore have an estimated lifespan of 1000~1500 hours (more or less due to operating conditions)

  2. Brushless DC Motors: Brushless motor systems offer better performance than brushed motors due to electrical commutation and closed-loop feedback but require drivers to electrically commutate the motor windings.

Stepper Motors: Stepper motors are brushless DC motors that move in discrete steps. They have multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, one step at a time.

Servo Motors: A servo motor is any motor coupled with a feedback sensor to facilitate positioning; thus, servo motors are the backbone of robotics. Both rotary and linear actuators are used. Low-cost brushed DC motors are common, but are being superseded by brushless AC motors for high-performance applications.

Useful Reference Material:

  1. Motor Selection Basics: Types of Electric Motors
  2. The Differences Between Brushed and Brushless DC Motors
  3. Types of Electric Motors
  4. What is a Stepper Motor? | All About Stepper Motors | Adafruit Learning System