Motor types

As already described, there are different types of electric motors, but these can be further subdivided.

DC motor

DC motors are divided into two subgroups. On the one hand this would be the permanently excited and on the other hand the electrically excited DC motor. In a permanently excited DC motor, the stator is a permanent magnet and only the rotor is an electromagnet. This type of DC motor is used, for example, in car starters.

The other form would be the electrically excited DC motor. In this type of motor, both major components are electromagnets. In the case of electrically excited DC motors, a further distinction is made between series or main circuit motors and the shunt motor. The difference is that the stator and the rotor each have their own voltage source in a shunt motor. A main circuit motor has only one voltage source. These motors can also be operated with alternating current and are therefore also called universal motors.

AC and three-phase motors

The three-phase motor is also divided into two different types. On the one hand there is the synchronous motor and on the other hand the asynchronous motor. With an asynchronous motor, the frequency of the rotor lags behind that of the magnetic field. The synchronous motor is characterized by the fact that the frequency of the rotor and magnetic field is identical. This difference ensures that synchronous motors are significantly more efficient and can thus achieve efficiencies of up to 90%. The major disadvantage of synchronous motors is that they are very maintenance-intensive and expensive to manufacture. For these reasons, synchronous motors are rarely used, for example in compressors or ship propulsion systems. Synchronous machines are used more often as generators. So to generate electrical energy.

The three-phase asynchronous motor, on the other hand, is used much more frequently, as already mentioned in the article "Types of motors and their mode of operation, subsection three-phase asynchronous motor" . This is because this type of motor is cheap to manufacture and is considered very robust and low-maintenance.

Three-phase asynchronous motors can be found in almost all areas of drive technology. Examples of this would be fan systems, pumps or conveyor belts.

There are further sub-categories for three-phase machines. The most important sub-categories can be seen in the following diagram.