Electromagnetic speed regulating motor controller JDK-1 200KW Motor user Nanjing second speed controller Item NO.: 1942512

definition

A rotating motor whose output or input is defined as DC energy is called DC motor. It is a motor that can realize the mutual conversion of DC energy and mechanical energy. When it operates as a motor, it is a DC motor, which converts electric energy into mechanical energy; When operating as a generator, it is a DC generator, which converts mechanical energy into electrical energy.

Structure of DC motor

As can be seen from the working principle diagram of DC motor and generator, the structure of DC motor shall be composed of stator and rotor. The stationary part of DC motor is called stator. The main function of stator is to generate magnetic field, which is composed of base, main magnetic pole, commutator pole, end cover, bearing and brush device. The rotating part during operation is called rotor, which is mainly used to generate electromagnetic torque and induced electromotive force. It is the hub for energy conversion of DC motor, so it is usually called armature, which is composed of rotating shaft, armature core, armature winding, commutator and fan.

1. Stator

(1) Main magnetic pole

The main magnetic pole is used to generate air gap magnetic field. The main magnetic pole is composed of the core of the main magnetic pole and the excitation winding. Generally, the iron core is made of 0.5mm ~ 1.5mm thick silicon steel sheet by lamination and riveting. It is divided into pole body and pole shoe. The part with excitation winding on the top is called pole body, and the part widened below is called pole shoe. The pole shoe is wider than the pole body, which can not only adjust the distribution of magnetic field in the air gap, but also fix the excitation winding. The excitation winding is wound with insulated copper wire and sleeved on the core of the main magnetic pole. The whole main magnetic pole is fixed on the base with screws,

1 - commutator 2 - brush device 3 - base 4 - main magnetic pole 5 - commutation pole

6 - end cover 7 - fan 8 - armature winding 9 - armature core

2) Commutator pole

The function of commutation pole is to improve commutation and reduce the commutation spark that may be generated between brush and commutator during motor operation. It is generally installed between two adjacent main magnetic poles and is composed of commutation pole core and commutation pole winding, as shown in 8.6. The commutation pole winding is wound with insulated wires and sleeved on the commutation pole core. The number of commutation poles is equal to that of the main magnetic pole.

(3) Frame

The shell of the motor stator is called the base, as shown in Figure 3 in 8.4. The base has two functions: one is to fix the main magnetic pole and change the structure of the main magnetic pole in Figure 8.5

To the pole and end cover, and play the role of supporting and fixing the whole motor; 1 - main magnetic pole 2 - excitation winding 3 - base

Second, the base itself is also a part of the magnetic circuit, which constitutes the magnetic path between the magnetic poles. The part through which the magnetic flux passes is called the yoke. In order to ensure that the base has sufficient mechanical strength and good magnetic conductivity, it is generally made of steel castings or welded steel plates.

4) Brush device

The brush device is used to introduce or draw DC voltage and DC current, as shown in Figure 8.7. The brush device is composed of a brush, a brush holder, a brush rod and a brush rod seat. The brush is placed in the brush holder and compressed with a spring to make a good sliding contact between the brush and the commutator. The brush holder is fixed on the brush rod, which is installed on the ring-shaped brush rod seat and must be insulated from each other. The brush rod seat is installed on the end cover or bearing inner cover. The circumferential position can be adjusted and fixed after adjustment.

Fig. 1.6 commutator pole Fig. 1.7 brush device

1 - reversing pole core 1 - brush holder 2 - brush

2 - commutation pole winding 3 - compression spring 4 - brush braid

2. Rotor (armature)

(1) Armature core

The armature core is the main part of the main magnetic circuit and is used to embed the armature winding. Generally, the armature iron core is made of 0.5mm thick silicon steel sheet (the shape of the sheet is shown in Fig. 8.8 (a)), so as to reduce the eddy current loss and hysteresis loss in the armature iron core during motor operation. The stacked iron core is fixed on the rotating shaft or rotor support. The outer circle of the iron core is provided with an armature slot in which the armature winding is embedded.

(2) Armature winding

The function of armature winding is to generate electromagnetic torque and induced electromotive force. It is the key component of DC motor for energy conversion, so it is called armature. It is composed of many coils (hereinafter referred to as elements) connected according to a certain law. The coil is wound with high-strength enamelled wire or glass fiber wrapped flat copper wire. The coil edges of different coils are divided into upper and lower layers and embedded in the armature slot. Proper insulation must be provided between the coil and the iron core and between the upper and lower coil edges. In order to prevent the coil edge from being thrown out of the slot by centrifugal force, the slot is fixed with slot wedge, as shown in Figure 8.9. The termination part of the coil extending out of the slot shall be bound with thermosetting weftless glass tape.

(3) Commutator

In DC motor, the commutator is equipped with brush, which can convert the external DC power supply into alternating current in armature coil, so that the direction of electromagnetic torque is constant; In the DC generator, the commutator is equipped with

The brush can convert the alternating electromotive force induced in the armature coil into the DC electromotive force led out from the positive and negative brushes. The commutator is a cylinder composed of many commutators. The commutators are insulated with mica sheets. Figure 8.9 structure of armature slot

The fastening of the commutator is usually shown in Figure 8.10. The lower part of the commutator is made into pigeon 1 - slot wedge 2 - coil insulation 3 - armature conductor

Tail shape, both ends are fixed with steel V-shaped sleeve and V-shaped mica ring, and then 4-interlayer insulation, 5-slot insulation and 6-slot bottom insulation

Lock the nut.

4) Rotating shaft

The rotating shaft plays the supporting role of rotor rotation and needs to have certain mechanical strength and stiffness. It is generally processed from round steel.

Figure 8.10 commutator structure figure 8.11 single stack winding elements

1 - commutator 2 - connecting part 1 - head end 2 - end 3 - element side 4 - terminating part 5 - commutator

Reversible operation principle of DC motor

In principle, a DC motor can operate as either a motor or a generator. This principle is called reversible principle in motor theory. When the prime mover drives the armature winding to rotate between the main magnetic poles N and s, electromotive force is induced on the armature winding, which is rectified into DC by brush and commutator device, and then led to external load (or power grid) for external power supply. At this time, the motor operates as a DC generator. If an external DC power supply is used to direct the DC current to the armature winding through the brush commutator device, the current interacts with the magnetic field generated by the main magnetic pole N.S. to generate torque and drive the rotor to work with the mechanical load connected to it. At this time, the motor operates as a DC motor.

Classification of DC motors

According to the results, it is mainly divided into DC motor and DC generator

According to the type, it is mainly divided into DC brushless motor and DC brushless motor

The excitation mode of DC motor refers to the problem of how to supply power to the excitation winding and generate excitation magnetic flux to establish the main magnetic field. According to different excitation modes, DC motors can be divided into the following types.

Excitation mode of DC motor

1. Separately excited DC motor

The DC motor with no connection relationship between the excitation winding and the armature winding and powered by other DC power sources is called separately excited DC motor, and the wiring is shown in figure (a). In the figure, M represents the motor, and if it is a generator, G represents it. Permanent magnet DC motor can also be regarded as separately excited DC motor.

2. Shunt DC motor

The excitation winding and armature winding of Shunt DC motor are connected in parallel, and the wiring is shown in figure (b). As a shunt generator, the terminal voltage from the motor itself supplies power to the excitation winding; As a shunt motor, the excitation winding and armature share the same power supply, which is the same as that of separately excited DC motor in terms of performance.

3. Series excited DC motor

After the excitation winding of series excited DC motor is connected in series with armature winding, it is connected to DC power supply. The wiring is shown in figure (c). The excitation current of this DC motor is the armature current.

4. Compound DC motor

Compound excitation DC motor has two excitation windings of parallel excitation and series excitation, and the wiring is shown in figure (d). If the magnetic flux generated by series excitation winding is in the same direction as that generated by parallel excitation winding, it is called product compound excitation. If two magnetic fluxes have opposite directions, it is called differential compound excitation.

DC motors with different excitation modes have different characteristics. Generally, the main excitation modes of DC motor are parallel excitation, series excitation and compound excitation, and the main excitation modes of DC generator are separate excitation, parallel excitation and compound excitation.

DC generator

DC generator is a machine that converts mechanical energy into DC energy. It is mainly used as DC motor, electrolysis, electroplating, electric smelting, charging and excitation of alternator. Although power rectifier elements are also used where DC power is needed to turn AC into DC power, AC rectifier can not be compared with DC generator in terms of convenient use, operation reliability and some working performance.

DC motor nameplate

Domestic motor models are generally represented by Arabic numerals in capitalized English Pinyin letters. The format is as follows: some use capitalized Pinyin letters to represent the product code, the second part uses Arabic numerals to represent the design serial number, the third part uses Arabic numerals to represent the base number, and the fourth part uses Arabic numerals to represent the armature core length code.

Take Z2 --- 92 as an example: Z represents general purpose DC motor; 2 represents the design serial number and the second modification design; 9 refers to the frame serial number; 2 armature core length symbol.

Some characters have the following meanings:

Z series: General Purpose DC motor (such as Z2 Z3 Z4 Series)