Winding Definition in Motor

In a distributed winding, at least two stator teeth are always wrapped, as in this example in the image. The number of wrapped teeth is called coil step or step size and of course, you can also wrap more than 3, 4, 5 or more teeth. In a distributed winding, the windings overlap at the top and bottom of the electric motor, this area of the motor is also called the winding head. Due to the overlap, the winding head is larger with a distributed winding than with a concentrated winding. For very short electric motors, a concentrated winding is therefore usually used instead of a distributed winding. As a result, the ohmic losses of the winding head can be reduced. For longer electric motors, the influence of extraction head losses in relation to total losses is not so great. A very important advantage of a distributed winding for an electric motor is that the resulting rear electromagnetic field has a smooth, mainly sinusoidal characteristic. This means that the proportion of harmonics is very low and therefore also the losses in the stator fins and windings. Decentralized windings are used wherever high efficiency is required, such as in electric vehicles. Another advantage of distributed windings is the high synchronicity, which means that the torque ripple and therefore the motor noise are very low.

For this reason, distributed winding electric motors are mainly used to turn the spindles of machine tools, otherwise torque vibrations would have a negative effect on the quality of the workpiece. In a motor, the rotating part is called a rotor. The rotor includes the rotor winding as well as the rotor core. The rotor winding is powered by DC power. The rotor can be divided into two types, namely phase envelope and squirrel cage. In a study conducted at Lappeenranta University of Technology (LUT) in Finland, the research team created a prototype electric motor using fibers from woven carbon nanotubes as motor winding material. Their results showed that the designers were able to reduce joule losses in motor windings to half of current machines by replacing copper with carbon nanotube fibers. The wires are placed in a spiral in each layer.

Due to the direction of movement from one layer to another, which alternates between right and left, the wires intersect and locate in the space of the underlying layer. A bottom layer wire guide is not available. If the number of layers exceeds a certain limit, the structure cannot be maintained, and a wild coil is created. This can be avoided by using separate layer insulation, which is necessary anyway when the voltage difference between the layers exceeds the tension strength of the copper wire insulation. Due to the linear laying movement of the wire guide tube, the component to be wound is rotated in such a way that the wire is distributed throughout the winding space of the former. Rotary movement and laying movement are achieved by the use of computer-controlled motors. With respect to one turn of the axis of rotation and depending on the diameter of the wire, the axis of displacement of the wire guide tube is moved accordingly (not through). The winding of the motor is affected by the thickness of the wire and the associated intensity of the windings. The thinner the wire, the greater the winding of the motor can be.

This has several consequences: Since the last guide point of the wire is located on a nozzle or roller of a flyer arm, which moves on a fixed circular path that can only be moved in the direction of laying, accurate laying near the surface of the coil is impossible. Therefore, it is not easy to clearly place or even terminate the starting and end wires on the component to be wound. However, it is also possible to produce orthocyclic coils using the flyer winding process. Here, a self-guided behavior of the wire on the surface of the coil is advantageous. In the protruding pole configuration machine, the magnetic field pole can be generated with a winding wound approximately below the pole surface. In the non-projecting pole configuration, the winding can be distributed in the slots of the pole surface. A shielded polar motor contains a winding arranged around the polar part that maintains the phase of the magnetic field. Some types of motors include conductors with thicker metal such as metal sheets, otherwise ingots usually made of copper, if not aluminum. As a rule, these are driven by electromagnetic induction.

This type of winding structure creates an optimal filling factor (90.7%) for round wires. The windings of the top layer must be inserted into the grooves provided by the bottom layer. The 90° rotation of the wire when the hollow needle emerges puts a lot of pressure on the wire and makes it difficult to wind copper wires with a diameter greater than 1 mm. Orthocyclic winding with a needle reel is therefore only possible to a limited extent for these winding tasks. Motor winding refers to the type of winding of the electrical conductor to generate a magnetic field, which is used to drive the rotors into an electric motor – for example. a servomotor. 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, which means that resistance and waste heat also increase at higher speeds. In this way, a suitable motor winding can be used for each specific application. Baumüller electric motors are perfectly suited to all forms of drive in industry.

For a stator with 40 windings per tooth with a wire diameter of 0.5 mm, an orthocyclic winding design must be calculated. The available insulated cloakroom is geometrically defined and has an area of 35 mm2. Insulating paper with a thickness of 0.25 mm is used. Since the winding must be positioned largely parallel to the winding flange to meet an orthogonality condition, it is necessary to adjust the winding width to the number of revolutions per winding layer. In particular, in areas of cross-section of coil of non-circular shape, it is desirable to locate the transition area on the small side of the coil former, also known as the winding head. This is because non-circular coils are mounted on a sheet metal case or in a circular arrangement. The coils should be rather small to avoid contact with the neighboring coil or pack of sheets. Three winding geometries can be defined for orthocyclic round coils: The shaft winding includes parallel paths between the two brushed as well as positive and negative. The end part of the primary armature coil can be connected at some distance to the starting part of the next part of the armature coil switch. The conductors of this type of winding can be connected by two parallel paths in a machine mast. The number of parallel ports can be equal to the number of brushes used for high-voltage and low-current machines. Please click on the link to learn more about Lap Winding & Wave Winding.

The applications of electric motors are multiple. Different applications place different demands on the engine design. Some of these requirements are influenced by winding design and may include: However, a major challenge with copper as a motor winding material is its high density (8.96 g/cm3). It may not be the ideal material choice for applications requiring lightweight materials, such as airplanes and electric vehicles. Linear winding application for an external groove stator This is therefore an overview of motor winding theory. From the above information, we can finally conclude that windings are made with copper wires wrapped around a core to generate or receive electromagnetic energy. The wire used in the windings must be protected. But in some cases we can see the windings as bare copper, but it is simply covered with enamel. The most commonly used material for winding is copper. Aluminum can also be used, but it should be thicker to safely support a similar load. The copper winding allows for a tiny motor.

The objective of the distributed winding is to generate a sinusoidal distribution of magnetomotive force (MMF) in the air gap of the motor. This MMF is generated when a symmetrical set of three-phase alternating currents flows through the phase windings. It is the MMF, combined with the design of the motor`s magnetic circuit, that creates a flux wave in the air gap to produce the required motor torque. In combination with a serial connection, T-segments are often produced as a phase connection in the form of a toothed chain. As with the individual T-segments, linear winding technology and flyer winding technology are also used in this context. When winding the teeth, the last thread of the first tooth is led to the next tooth, and then serves as the starting thread for the second tooth. This process continues based on the number of sub-segments of a phase. The design of the components shows no significant difference from that of conventional simple teeth. The main reason for treating T-segments into a dental chain is the reduced number of touch points.

Six contact points are required for three single-tooth poles. However, only two points of contact are required if the abovementioned arrangement in the winding machine is adopted. When using high current with low operating power, this type of manufacturing is particularly advantageous because it reduces contact resistors and possible errors. However, it is very complex to shape dental chains into a complete stator, which is a disadvantage.