Basics: Motor winding

Matthias Beetz, Baumüller Nürnberg GmbH

Read min.

The motor winding refers to the arrangement of electrical conductors that generate the magnetic field in an electric motor, which in turn drives the rotors. The type of winding and the properties of the conductors used also influence the specifications of the motor, in some cases to a great extent, and allow the design to be individually adapted to the intended use.

The following glossary article includes

Index

Definition of motor winding

The motor winding refers to the winding of the electrical conductor in the motor between the housing and the rotor. The conductor consists of a wire with high electrical conductivity and can be used in various thicknesses. The smaller the diameter of the wire, the tighter the windings that can be wound. This significantly changes the operating behavior of the motor because it also changes the type of magnetic field generated when current flows through the motor winding.

Functioning and influence on operating behavior

The motor winding is influenced by the thickness of the wire and the associated intensity of the windings. The thinner the wire, the more motor winding can be achieved. This has several consequences:

The strength of the magnetic field increases with each winding.
As a result, the torque also increases.
The electromagnetic force in the overall system increases.
This increases the countervoltage, which counteracts the operating voltage as soon as the speeds increase.

These properties already reveal the application for narrower and finer motor windings. Since the strength of the magnetic field is very high, an extremely high torque and therefore a correspondingly large effective force can be generated at low speeds. At higher speeds, however, the torque drops all the more due to the steadily decreasing countervoltage. Another side effect is that there are greater heat losses due to electrical resistance. This requires appropriate cooling.

Resulting applications

The narrow motor winding just described and the corresponding consequential effects serve as a basis for specific applications. These require high torque at low speed. One possible application would thus be the torque motor, such as the Baumüller DST2. Here, extremely high forces are generated, which are common in extruders, servo presses, and shredders, to name a few examples. These applications demand not high speeds, but rather a high force, which, in the specific case of the DST2, can go as high as 60,000 Nm.

Summary

The motor winding refers to the type of winding of the electrical conductor for generating a magnetic field used to drive the rotors in an electric motor – e.g. a servo motor. The design determines the available torque, the electromagnetic force in the system, the electrical resistance, and therefore the application. The tighter the winding, the higher the torque and force generated – with resistance and waste heat also increasing at higher speeds. This way, a suitable motor winding can be employed for each specific application. Baumüller electric motors are perfectly matched to all possible forms of drives in industry.

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Matthias Beetz
Training Engineer Academy I Baumüller Nürnberg GmbH

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