1-2. Components of a Motor

The following is a brief explanation of principal materials in a motor:

(1) Wire

Wire is the material the current travels through. The wire is also called a conductor. Wires are typically made of copper; however, aluminum is occasionally used.

Lead wire is used to supply power to the motor from the power supply and for the winding that is wound and connected inside the motor. In English, winding is called magnet wire, which is the wire used to generate a magnetic field. In Japan, winding is also referred to as enameled wire after the enamel resin that is used as insulation material (to be described).

At present, high-polymer materials are used for insulation, but habitual naming criteria of enameled wire are still used.

As a component of motor winding, the term "enameled wire" is used in Japanese. Enameled wire is referred to as magnet wire in English.

(2) Core

(Iron) core is the path for flux and is made of iron as the name (iron) core suggests. Moreover, a core used to combine two magnets with flux is called a yoke.

Iron for mechanical structures and that for cores contain different types of accessory ingredients. Iron for mechanical structures contains carbon (C), while iron for cores is mixed with silicon (Si) and called silicon steel. In the case of a motor, the core is divided into the stator core and the rotor core, and a magnetic circuit is configured through the air gap in between. Since the magnetic pole of the stator core configuring the magnetic circuit of electromagnetic field DC motors is excited by direct current, the core does not need to be laminated; soft steel is used instead.

On the other hand, laminated core is used for a rotor core configuring the armature circuit as the flux changes with rotation. Also, permanent magnets are often used for the magnetic pole of small DC motors. Cores for the stator of synchronous motors and the stator and rotor of induction motors are excited by alternating current, therefore laminated core is used for each of them.

(3) Insulator (Insulating material)

Insulators prevent electric current from flowing to any locations other than the desired one, and materials that have such characteristics are called insulating materials.

Rubber, enamel, and other high-molecular compounds or resins, paper, mica, glass fiber, etc. are used as insulators.

(4) Permanent magnet

Among materials that make up a motor, a permanent magnet is important as it generates magnetic fields. Permanent magnets can be said to be a type of iron-based alloy or oxide.