An engine or motor is a machine designed to convert one form of energy into mechanical energy. An electric motor is an electrical machine that converts electrical energy into mechanical energy. A stepper motor is a type of DC electric motor.

Electric Motors

Most electric motors operate through the interaction between an electric motor’s magnetic field and winding currents to generate force. Electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or by alternating current (AC) sources, such as from the power grid, inverters or generators. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, and so on.

Electric motors are used to produce linear or rotary force (torque), and should be distinguished from devices such as magnetic solenoids and loudspeakers that convert electricity into motion but do not generate usable mechanical powers, which are respectively referred to as actuators and transducers.

Stepper Motor

A stepper motor or step motor or stepping motor is a brushless DC electric motor that divides a full rotation into a number of equal steps. The motor’s position can then be commanded to move and hold at one of these steps without any position sensor for feedback (an open-loop controller), as long as the motor is carefully sized to the application in respect to torque and speed.

Switched reluctance motors are very large stepping motors with a reduced pole count, and generally are closed-loop commutated.

Electric motors are broadly classified into two categories as follows: 1. AC Motors 2. DC Motors

Advantages of DC motors:
  • It is easy to control their speed in a wide range; their torque-speed characteristic has, historically, been easier to tailor than that of all AC motor categories. This is why most traction and servo motors have been DC machines. For example, motors for driving rail vehicles were, until recently, exclusively DC machines.
  • Their reduced overall dimensions permit a considerable space saving which let the manufacturer of the machines or of plants not to be conditioned by the exaggerated dimensions of circular motors.

Disadvantages of DC motors
  • Since they need brushes to connect the rotor winding. Brush wear occurs, and it increases dramatically in low‚Äźpressure environment. So they cannot be used in artificial hearts. If used on aircraft, the brushes would need replacement after one hour of operation.
  • Sparks from the brushes may cause explosion if the environment contains explosive materials.
  • RF noise from the brushes may interfere with nearby TV sets, or electronic devices, Etc.
  • DC motors are also expensive relative to AC motors.

DC motors are divided mainly to: 1. Brush DC motors (BDC) 2. Brushless DC motors (BLDC) Read more

AC motors

Alternating current (AC) motors use an electrical current, which reverses its direction at regular intervals. The main advantage of DC motors over AC motors is that speed is more difficult to control for AC motors. To compensate for this, AC motors can be equipped with variable frequency drives but the improved speed control comes together with a reduced power quality.

AC motors in common use today may be divided into two broad categories: 1. Induction (asynchronous) motors 2. Synchronous motors 3. Linear Motors Read more