Construction of Small Motors

The constructions of the “brushed DC motors”, “brushless DC motors”, and “stepping motors” which are small motors considered in the discussion of “Motor Driving” in the previous article are here summarized.

Construction of Small Motors

We begin by summarizing and comparing the constructions of the three types of motors, which are stepping motors, brushed DC motors, and brushless DC motors. The basic constituent components of these motors are coils, magnets, and rotors; depending on the type, the coils may be stationary, or the magnets may be stationary.

The constituents illustrated in the diagram are explained below. Details are different for each construction, and these should be considered to be representative for the categories.

In this stepping motor, coils are fixed in place on the outside, and magnets rotate on the inside.

In this brushed DC motor, magnets are fixed on the outside, and coils rotate on the inside. The coils have a brush and commutator which serve to supply current and perform switching.

In this brushless motor, coils are fixed on the outside, and magnets rotate on the inside.

Here, it should be understood that, depending on the motor type, there may be some differences in construction even when the basic components are the same. Details for each motor type are explained in respective sections.