Specializing in the design and manufacture of automotive motor armatures and stators.

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Induced electromotive force and current of automotive armature windings

Release Time:

2022-08-11

   Automotive Armature A basic understanding is that when a winding carries current in a magnetic field, a force acts on the winding. A more advanced understanding is that when a winding carries current in a magnetic field, it generates another magnetic field, and the interaction between the two fields produces torque. From an electron's perspective, the current experiences a force in the magnetic field. The latter understanding involves the interaction of two magnetic fields.

  It is generally understood that there is a magnetic field that generates an induced electromotive force, and the current in the winding generates another magnetic field. The interaction between the two magnetic fields produces torque. However, if the two combine into a single magnetic field, how this magnetic field produces torque requires an understanding of tensor laws. The magnetic force that generates the armature induced electromotive force is called the air gap magnetic flux line, and the magnetic flux is called the air gap magnetic flux line. The air gap magnetic flux line and the induced armature reduce the frequency relationship, thereby reducing the pi/2 phase relationship. This is a very clear and measurable physical quantity. The relationship with the armature winding current is also obvious.

  Two main categories of flowing armature windings. Used in DC motors and AC motors, respectively.

  The armature consists of an armature core and an armature winding. The armature winding is the circuit part of a DC motor, and is the part that converts electrical energy through the generation of induced electromotive force and electromagnetic torque (a generator converts mechanical energy into electrical energy). The armature core is part of the armature circuit and also supports the armature winding, which is embedded in the slots of the armature core.

  The principle of induced armature in DC and AC motors is roughly the same. The current in the armature winding of a DC motor is also AC, and must be output through a commutator to be DC. AC motors are divided into induction motors (asynchronous motors) and synchronous motors. Induction motors are divided into squirrel-cage rotors and wound rotors according to the rotor structure. Induction motors use stator windings to generate a magnetic field, and rotor windings to perform energy conversion. Synchronous motors use rotor windings to generate a magnetic field and stator windings to perform energy conversion.

  An automotive armature usually refers to the part of a motor that requires an external power supply. In a DC motor, the armature is the rotor; in an AC motor, the armature is the stator.

  1. Single-wave winding

  The characteristic of a single-wave winding is that the two commutator segments connected to the ends of each coil are far apart, and the resultant pitch y=yk is greater than y1. After the two coils are connected, they become a wave, called a wave winding. The difference from a lap winding lies in the commutator pitch yk. Since the induced electromotive forces of the two connected coils must be in the same direction, the corresponding angles of the two connected coils must be under the same polarity pole. Therefore, the commutator pitch is approximately equal to two poles. Its pitch is the same as the stack group, close to or equal to the pole pitch.

  2. Multiple-wave windings

  In a wave winding, after P (number of pole pairs) coils are connected around the armature, if the commutator segments are not adjacent to the starting commutator segment, and differ by 2, 3, or M segments, the resulting winding is equivalent to a combination of 2, 3, or M short-wave windings. This is called a multiple-wave winding. Frog (mixed) winding

  For large motors, sometimes a mixed armature winding with both lap and wave windings is used, called a mixed winding. Its winding structure is very similar to a frog, so it is also called a frog-type winding. The shape of the coil resembles a frog, hence the name frog-shaped winding. This frog-type winding itself has a perfect equalizing effect, so no additional equalizing windings are needed.


Automotive armature

09-13

2022

Methods for winding the armature of a DC brushless automotive motor

The method for winding the armature winding of a DC brushless car motor is to leave a section of the cable end free and tie it tightly to the shaft. Hold the car armature with one hand, and wind the coil inductance clockwise with the other hand. Taking a five-slot armature as an example, the first coil is 1-5, the second coil is 2-6, then 3-7..., and so on. The sides of many components are on the next layer. The 5-9 components have one side on the next layer and the other side on the top layer. The sides of many components are on the top layer. In order to ensure the insulation between the top layer and the next layer components, it is advisable to place 0.1-0.15mm thick insulating paper pads in between. When the coil inductance in the slot reaches a certain level, a crossbar is needed to make it reach the bottom of the slot. When winding the coil inductance, the wire should be tightened first. Whether in the slot or the wire connection part, it is necessary to prevent the occurrence of crossed turns to prevent excessive space occupation and short circuit between turns due to partial stress of the wire. After all the windings are wound, the wire ends of the same winding component are bundled together, then the insulation layer of the wire connector is removed, different color waterproof sleeves are used, and they are embedded in the corresponding commutator segments. The important role of the armature in a DC brushless motor: DC motor,

08-22

2022

Design rules for automotive armatures

Automotive armature manufacturers indicate that single-layer windings are not suitable for large-capacity motors, and small-capacity motors should not be double-layered. The magnetic flux density of the motor core should not be too high or too low. When the frequency and thickness of the silicon steel sheet core material are constant, the iron loss depends on the magnetic flux density. If the magnetic flux density is too high, the iron loss increases, and the motor efficiency decreases. The increased heat from the iron core increases the motor temperature, and the increased excitation power increases the motor power factor, so the magnetic flux density of the core should not be too high. Try to avoid excessive saturation of the magnetization curve. If the magnetic density is too low, it will increase the amount of motor material used, increasing the cost. The rotor teeth are narrow, the magnetic density is high, the slot entry wire is large, that is, the automotive armature slots are large. Automotive armature manufacturers indicate that due to poor air conduction, there are many gaps in the slots, affecting the coils and easily damaging the heat dissipation of the insulation material, accelerating the increase in motor temperature. The slot fill factor of the motor slots cannot be too high or too low. Usually, the slot fill factor for low-speed motors is 75% to 85%, which can effectively prevent the enamelled wire from loosening in the slots. The design of the motor rotor slot shape should use parallel trapezoidal recesses as much as possible, and the edges of the recesses should not have sharp corners. Try to use a circular bottom recess, because the circular slot is filled with aluminum, which is easy to injection mold and the stator chip is easy to insert. The coil current density should not be...

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