1.4. Comparison of different types of stepper motors

Permanent-magnet motors:

• They have high torque due to the incorporation of a magnet on the rotor.
• Step angles are available are large.
• The size is conditioned by the permanent magnet rotor and the pitch, you can get small sizes.
• Because the magnetization of the rotor, this engine have a residual torque or braking torque.
• The damping effect generated by the magnetization limits the range of speeds.

Variable-reluctance motors:

• Not incorporating a permanent magnet, the rotor can be manufactured with a small diameter, and therefore the engine size is also reduced.
• With a small rotor diameter, the moment of inertia of this also is providing a high dynamic range (high speed), and a good starting torque.
• The step angle is limited, the diameter of stator poles limits the number of coils it can hold.
• It has no residual holding torque when turned off, which is often a disadvantage.
• They are much less torque, but making it easier.

"Hybrid engines:

• Possible to obtain small step angles without using a large number of phases.
• They have a good dynamic range, from permanent magnet motors and variable reluctance.
• By incorporating magnetization, show the residual holding torque without power.
• The measures are contained without reaching the VR motor due to the location of the permanent magnet in the stator.
• Produces high torque produced by force of reluctance and VR motors.