Servo Motor – This type of motor is basically a brushed DC motor with some form of positional feedback control connected to the rotor shaft.They are generally smaller but more expensive than conventional brushed type DC motors because they use “Hall effect” switches in the stator to produce the required stator field rotational sequence but they have better torque/speed characteristics, are more efficient and have a longer operating life than equivalent brushed types. Brushless Motor – This type of motor produce a magnetic field in the rotor by using permanent magnets attached to it and commutation is achieved electronically.Generally brushed DC motors are cheap, small and easily controlled. The stators (the stationary part) magnetic field is produced by using either a wound stator field winding or by permanent magnets. Brushed Motor – This type of motor produces a magnetic field in a wound rotor (the part that rotates) by passing an electrical current through a commutator and carbon brush assembly, hence the term “Brushed”.The result is that there are basically three types of DC Motor available. A DC motor consists of two parts, a “Stator” which is the stationary part and a “Rotor” which is the rotating part.
The DC Motor or Direct Current Motor to give it its full title, is the most commonly used actuator for producing continuous movement and whose speed of rotation can easily be controlled, making them ideal for use in applications were speed control, servo type control, and/or positioning is required. In this tutorial on electrical motors we will look only at simple light duty DC Motors and Stepper Motors which are used in many different types of electronic, positional control, microprocessor, PIC and robotic type circuits. AC Motors are generally used in high power single or multi-phase industrial applications were a constant rotational torque and speed is required to control large loads such as fans or pumps.