20 horsepower dc motors manufacturer india
3、 Three phase asynchronous motor
The structure of the three-phase asynchronous motor is similar to that of the single-phase asynchronous motor. Three-phase windings (single-layer chain type, single-layer concentric type and single-layer cross type) are embedded in the stator core slot. After the stator winding is connected to the three-phase AC power supply, the rotating magnetic field generated by the winding current generates the induced current in the rotor conductor. Under the interaction of the induced current and the air gap rotating magnetic field, the rotor generates an electromagnetic rotating cabinet (i.e. asynchronous rotating cabinet) to make the motor rotate.
4、 Shaded pole motor
Shaded pole motor is the simplest type of one-way AC motor,
Cage type inclined slot cast aluminum rotor is usually used. It is divided into salient pole covered pole motor and hidden pole covered pole motor according to the different stator shape and structure.
The stator core of salient pole shaded pole motor is a square, rectangular or circular magnetic field frame with protruding magnetic poles. Each magnetic pole is provided with one or more short-circuit copper rings that play an auxiliary role, that is, the shaded pole winding. The concentrated winding on the salient pole is used as the main winding.
The stator core of the hidden pole shaded pole motor is the same as that of the ordinary single-phase motor. The stator winding adopts the distributed winding, and the main winding is distributed in the stator slot. The shaded pole winding is not short circuited copper ring, but is wound into a distributed winding with thick enamelled wire (short circuited automatically after being connected in series) and embedded in the stator slot (about 2/3 of the total slots), playing the role of an auxiliary group. The main winding and the shaded pole winding are at a certain angle in space.
When the main winding of the shaded pole motor is energized, the shaded pole winding will also generate induced current, so that the magnetic flux of the covered part of the stator pole and the uncovered part of the stator pole will rotate in the direction of the covered part.
5、 Single phase series motor
The stator of single-phase series excitation motor is composed of salient pole iron core and excitation winding, and the rotor is composed of salient pole iron core, armature winding, commutator and rotating shaft. A series circuit is formed between the excitation winding and the armature winding through an electric brush and a commutator.
Single phase series excited motor belongs to AC and DC dual-purpose motor. It can work with both AC power supply and DC power supply.
Synchronous motor
Synchronous motor and induction motor are common AC motors. Features: during steady-state operation, there is a constant relationship between rotor speed and grid frequency, n=ns=60f/p, and NS becomes synchronous speed. If the frequency of the power grid is constant, the speed of the synchronous motor in the steady state is constant regardless of the load. Synchronous motor is divided into synchronous generator and synchronous motor. The AC machine in modern power plant is mainly synchronous motor.
working principle
Establishment of main magnetic field: the excitation winding is connected with DC excitation current to establish the excitation magnetic field between polarity phases, that is, the main magnetic field is established.
20 horsepower dc motors manufacturer india
Current carrying conductor: the three-phase symmetrical armature winding acts as the power winding and becomes the carrier of induced potential or induced current.
Cutting movement: the prime mover drives the rotor to rotate (input mechanical energy to the motor), the excitation magnetic field between polarity phases rotates with the shaft and cuts each phase winding of the stator in sequence (equivalent to the conductor of the winding cutting the excitation magnetic field in reverse). [1]
Generation of alternating potential: due to the relative cutting movement between the armature winding and the main magnetic field, the armature winding will induce a three-phase symmetrical alternating potential whose size and direction change periodically. AC power supply can be provided through outgoing line.
Alternating and symmetry: the polarity of the induced potential alternates due to the alternating polarity of the rotating magnetic field; Due to the symmetry of armature winding, the three-phase symmetry of induced emf is ensured. [1]
1、 AC synchronous motor
AC synchronous motor is a kind of constant speed drive motor. Its rotor speed maintains a constant proportional relationship with the power frequency. It is widely used in electronic instruments, modern office equipment, textile machinery and so on.
2、 Permanent magnet synchronous motor
Permanent magnet synchronous motor belongs to asynchronous starting permanent magnet synchronous motor. Its magnetic field system is composed of one or more permanent magnets. Usually, the magnetic poles of the cage rotor welded with cast aluminum or copper bars are equipped with permanent magnets according to the required number of poles. The stator structure is similar to that of asynchronous motor.
When the stator winding is powered on, the motor starts to rotate based on the principle of asynchronous motor and accelerates to the synchronous speed, the synchronous electromagnetic torque generated by the rotor permanent magnetic field and the stator magnetic field (the electromagnetic torque generated by the rotor permanent magnetic field and the reluctance torque generated by the stator magnetic field) pulls the rotor into synchronization, and the motor enters into synchronous operation.
Reluctance synchronous motor reluctance synchronous motor, also known as reactive synchronous motor, is a synchronous motor that generates reluctance torque by using the unequal cross axis and direct axis reluctance of the rotor. Its stator structure is similar to that of asynchronous motor, but the rotor structure is different.
3、 Reluctance synchronous motor
Evolved from the same cage type asynchronous motor, in order to make the motor produce asynchronous starting torque, the rotor is also equipped with cage type cast aluminum winding resistance. The rotor is provided with a reaction slot corresponding to the number of stator poles (only the salient pole part, no excitation winding and permanent magnet) to generate reluctance synchronous torque. According to the different structures of the reaction tank on the rotor, it can be divided into internal reaction rotor, external reaction rotor and internal and external reaction rotor. Among them, the external reaction rotor reaction tank is opened to the outer circle of the rotor, so that the air gap in the direction of direct axis and quadrature axis is different. The inner reactive rotor is provided with grooves, which blocks the magnetic flux in the quadrature axis direction and increases the magnetic resistance. The internal and external reactive rotors combine the structural characteristics of the above two rotors, and the direct axis and quadrature axis are quite different, so that the force energy of the motor is large. Reluctance synchronous motors are also divided into single-phase capacitor operation type, single-phase capacitor starting type, single-phase double value capacitor type and other types.
20 horsepower dc motors manufacturer india
4、 Hysteresis synchronous motor
Hysteresis synchronous motor is a kind of synchronous motor which uses hysteresis materials to produce hysteresis torque. It is divided into inner rotor hysteresis synchronous motor, outer rotor hysteresis synchronous motor and single-phase shaded pole hysteresis synchronous motor.
The rotor structure of the inner rotor hysteresis synchronous motor is the hidden pole type, the appearance is a smooth cylinder, there is no winding on the rotor, but there is an annular effective layer made of hysteresis material on the outer circle of the core.
After the stator winding is powered on,
The generated rotating magnetic field causes the hysteresis rotor to generate asynchronous torque and start to rotate, and then it is pulled into the synchronous operation state by itself. When the motor operates asynchronously, the stator rotating magnetic field magnetizes the rotor repeatedly with slip frequency; During synchronous operation, the hysteresis material on the rotor is magnetized and permanent magnetic poles appear, resulting in synchronous torque. The soft starter uses the three-phase anti parallel thyristor as the voltage regulator, which is connected between the power supply and the motor stator. This circuit is like a three-phase fully controlled bridge rectifier circuit. When the soft starter is used to start the motor, the output voltage of the thyristor will gradually increase, and the motor will gradually accelerate until the thyristor is fully turned on. The motor operates on the mechanical characteristics of the rated voltage to achieve smooth starting, reduce the starting current and avoid starting overcurrent tripping. When the motor reaches the rated speed, the starting process ends, and the soft starter automatically replaces the completed thyristor with the bypass contactor to provide the rated voltage for the normal operation of the motor, so as to reduce the heat loss of the thyristor, prolong the service life of the soft starter, improve its working efficiency, and avoid harmonic pollution in the power grid. The soft starter also provides the soft stop function. The soft stop process is opposite to the soft start process. The voltage gradually decreases and the number of revolutions gradually drops to zero to avoid the torque impact caused by free stop.
20 horsepower dc motors manufacturer india
Gear motor
Reduction motor refers to the integration of reducer and motor (motor). This kind of integrated body can also be called gear motor or gear motor. It is usually supplied in complete sets after integrated assembly by a professional reducer manufacturer. Reduction motors are widely used in iron and steel industry, machinery industry and so on. The advantage of using reduction motor is to simplify the design and save space.
1. The reduction motor is manufactured according to the international technical requirements and has a high scientific and technological content.
2. Space saving, reliable and durable, high overload bearing capacity, power up to 95kw.
3. Low energy consumption, superior performance, reducer efficiency up to 95%.
4. Low vibration, low noise, high energy saving, high-quality steel material, steel cast iron box, gear surface after high-frequency heat treatment.
5. After precision machining, the positioning accuracy is ensured. All these constitute the gear reduction motor of the gear transmission assembly, which is equipped with various motors, forming electromechanical integration, and completely ensuring the quality characteristics of the product.
6. The product adopts the design idea of serialization and modularization, which has a wide range of adaptability. This series of products have extremely many motor combinations, installation positions and structural schemes, and can choose any speed and various structural forms according to actual needs.
Reduction motor classification:
1. High power gear motor
2. Coaxial helical gear motor
3. Parallel shaft helical gear reduction motor
4. Spiral bevel gear reduction motor
5. YCJ series gear reduction motor
The reduction motor is widely used in the reduction transmission mechanism of various general mechanical equipment, such as metallurgy, mining, hoisting, transportation, cement, construction, chemical industry, textile, printing and dyeing, pharmaceutical and so on.
Variable frequency motor
Frequency conversion technology actually uses the principle of motor control to control the motor through the so-called frequency converter. The motor used for such control is called variable frequency motor.
Common variable frequency motors include three-phase asynchronous motor, DC brushless motor, AC brushless motor and switched reluctance motor.
Control principle of variable frequency motor
Generally, the control strategies of variable frequency motor are: constant torque control at base speed, constant power control above base speed, and field weakening control in ultra-high speed range.
Base speed: because the motor will generate back electromotive force when it is running, and the size of back electromotive force is usually proportional to the speed. Therefore, when the motor runs to a certain speed, because the back EMF is the same as the applied voltage, the speed at this time is called the base speed.
20 horsepower dc motors manufacturer india
Constant torque control: the motor performs constant torque control at base speed. At this time, the back electromotive force E of the motor is directly proportional to the speed of the motor. In addition, the output power of the motor is directly proportional to the product of the torque and speed of the motor, so the motor power is directly proportional to the speed at this time.
Constant power control: when the motor exceeds the base speed, the back EMF of the motor is basically kept constant by adjusting the motor excitation current, so as to improve the speed of the motor. At this time, the output power of the motor remains basically constant, but the motor torque decreases in inverse proportion to the speed.
Field weakening control: when the motor speed exceeds a certain value, the excitation current is quite small and can hardly be adjusted. At this time, the field weakening control stage is entered.
Motor speed regulation and control is one of the basic technologies of various industrial and agricultural machinery, office and livelihood Electrical equipment. With the amazing development of power electronics technology and microelectronics technology, the AC speed regulation mode of "special variable frequency induction motor + frequency converter" is leading a new generation of change to replace the traditional speed regulation mode in the field of speed regulation with its excellent performance and economy. The good news it brings to all walks of life is that it greatly improves the degree of mechanical automation and production efficiency, saves energy, improves the product qualification rate and product quality, correspondingly improves the capacity of power supply system, miniaturizes equipment and increases comfort. At present, it is replacing the traditional mechanical speed regulation and DC speed regulation schemes at a very fast speed.
Due to the particularity of variable frequency power supply and the requirements of the system for high-speed or low-speed operation, speed dynamic response and so on, the motor as the main power body has put forward harsh requirements, which has brought new topics in electromagnetic, structure and insulation to the motor.
