The winding is the heart of the motor. Different motors, different manufacturers, and different machining processes will correspond to different winding types. Different winding types are selected based on the realization of specific characteristics. The structure is simple, easy to manufacture and maintain, and safe and reliable.
The DC motor armature winding is the same as the AC motor winding. The relationship between the coils should make the potential of a certain number of conductors generate a large potential and save the non-ferrous metals and insulating materials as much as possible. However, it also has its unique characteristics: the coils are connected by commutators, and the connection relationship should be Make sure the commutation is good. Ms. Join us today to talk about the winding type and characteristics of DC motors.
1 DC motor armature winding terminology
● Commutator - A device that converts the AC potential inside the armature winding into a DC potential between brushes by mechanical switching, consisting of a number of commutating segments that are insulated from each other.
● Components - Single or multiple turns of coils connected to two commutator segments at each end.
● Component Edges - Two components in each slot are placed in the slot to cut the magnetic flux and the effective side of the induced potential.
● Virtual slot - In order to improve the performance of the motor, it is often necessary to use more components to form the armature winding, and the armature core sometimes does not open too many slots, so only a few components can be placed in the upper and lower layers of each slot. side. To clarify the exact location of each component edge, the concept of "virtual slot" is introduced. Each layer in the slot has u component edges, and each actual slot contains u "virtual slots", and each of the upper and lower layers of the "virtual slot" has a component edge. The relationship between the actual number of slots Z and the number of virtual slots Zi is Zi=uZ.
2 DC motor armature winding characterization and its pitch
The characteristics of DC motor armature windings are characterized by the number of slots, the number of components, the number of commutators and various pitches. Since each component has two component sides, each of the commutator segments is connected to the upper component side and the lower component edge at the same time, so the component number S must be equal to the number of commutator segments K, that is, S=K. As for the winding pitch, the first pitch y1, the second pitch y2, the combined pitch y, and the commutator pitch yk can be divided.
● The first pitch y1
The distance that the two component sides of each component span across the armature surface is referred to as the first pitch or the back pitch of the winding, expressed as the number of virtual slots spanned.
● Second pitch y2
In the two elements in which the same commutator segments are connected in series, the distance between the lower element side of the first element and the upper element side of the second element on the armature surface is called the second pitch or the front pitch, and is also used. The number of virtual slots is calculated.
● Synthetic pitch y
The distance of the corresponding side of the two element sides in series on the armature surface is called the synthetic pitch y, and its size is also calculated by the number of virtual grooves. The relationship between the synthetic pitch y and the first pitch y1 and the second pitch y2 is: y=y1+y2.
● commutator pitch yk
The distance between the two commutator segments connected at each end of each element on the commutator surface is called the commutator pitch and is represented by the number of commutator segments. The composite pitch y and the commutator pitch yk are always equal, ie: y = yk.
3 DC motor armature winding type
The armature windings of DC motors can be divided into five types: single-stack windings, multiple-stack windings, single-wave windings, complex-wave windings, and frog-shaped windings, that is, stacked and wave-wound hybrid windings.
● Single winding
In a single winding, the adjacent elements under the same magnetic pole are sequentially connected in series, and the combined pitch y=yk=+1 or -1. When winding such a winding, any two components in series are the one that is next to the previous one, so it is called a stacked winding. If y = yk = +1, the winding moves to the right, referred to as the "right row" winding; if y = yk = -1, the winding moves to the left, referred to as the "left row" winding. Each component of the left-row winding is connected to the two short-circuit wires of the commutator, and the copper is used more, which is rarely used. Therefore, the winding of the winding is often a right-row winding.
●Multiple winding
In the stacked winding, if the corresponding element sides of the two elements connected in series are not different from each other, but are different by 2, 3 or generally m virtual grooves, correspondingly the commutation of the two ends of each element The slices are not adjacent segments, but are separated by 2, 3 or m segments. According to this rule, the series is wound up, and the first component is wound up. 1/2, 1/3 or 1/m of the total component is connected in series, so it is necessary to go through 2 weeks, 3 weeks or generally m weeks to complete all the components. This type of winding is called a winding winding. . Obviously, the winding winding is composed of 2, 3 or generally m single winding windings.
●Single wave winding
The characteristic of the single-wave winding is that the two commutating segments connected at both ends of each component are far apart, and the combined pitch y=yk>y1 (first pitch), the two components are undulated after being connected in series, so Wave windings. The difference between it and the stacked winding is at the commutator pitch yk: since the induced potentials of the two series-connected components should be in the same direction, the corresponding sides of the two connected components should be under the same polarity magnetic pole, so The commutation pitch is approximately equal to two pole pitches. Its first pitch is the same as the stack winding, nearly equal to or equal to one pole pitch.
●Complex winding
In the wave winding, if p (polar logarithmic) elements are connected in series around the armature, the phasewise connected commutator is not adjacent to the starting commutator, but is different from it by 2, 3 Or m-piece, the resulting winding is equivalent to two, three or m single-wave windings combined together, called a complex winding.
●Frog type (mixed) winding
In large motors, armature windings that are a mixture of stacked windings and wave windings are sometimes used, called hybrid windings. Because its winding element looks like a frog, it is also called a frog-shaped winding. The coil is shaped like a frog, so it is called a frog-shaped winding. The frog-shaped winding itself has a perfect pressure equalization function, so there is no need to connect the equalizing line.
