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The principle of the DC motor of the internal mixer/open mixer is relatively simple, but the structure is complex and inconvenient to maintain. The AC motor has a complex principle but a relatively simple structure and is easier to maintain than a DC motor, but the power-saving effect is not ideal. The permanent magnet motor has higher efficiency than an AC motor and is more suitable for low-load internal mixers/open mixers machine conditions.
Internal mixer/open mixer DC motor introduces current into the rotor armature through brushes and commutators so that the rotor is forced to rotate in the stator magnetic field.
The AC motor passes alternating current into the stator winding, thereby generating a rotating magnetic field in the air gap of the stator and rotor, and the rotating magnetic field generates an induced current in the rotor winding, which in turn causes the rotor to rotate under force in the stator magnetic field. The speed regulation of the DC motor is simple, but the application is limited. AC motor speed regulation is relatively complex, but it is widely used due to the use of AC power. The AC speed regulation is to change the speed of the motor by changing the frequency of the AC power supply, and the DC is to adjust the armature voltage to change the speed. Nowadays, AC permanent magnet speed regulation is often used, which can save energy.
The DC motor has a fast response, large starting torque, and can provide rated torque from zero speed to rated speed. The performance of the torque, the armature magnetic field, and the rotor magnetic field must be maintained at 90°, which requires carbon brushes and commutators. Carbon brushes and commutators will generate sparks and carbon powder when the motor rotates, so in addition to causing damage to the components, the application is also limited.
The AC motor has no carbon brushes and commutators. It is maintenance-free, sturdy, and widely used. However, in order to achieve the performance equivalent to the DC motor, complex control technology can be used to achieve it. AC motors are divided into two categories: asynchronous motors and synchronous motors. Asynchronous motors are divided into single-phase asynchronous motors, two-phase asynchronous motors, and three-phase asynchronous motors according to the number of stator phases. The three-phase asynchronous motor has a simple structure, reliable operation, and low cost. However, energy consumption is still high under low load conditions, and the purpose of energy saving and consumption reduction cannot be achieved. At present, the permanent magnet synchronous motor has mature control technology, reliable operation, and low load and low-speed operation. It can maintain high motor efficiency and realize energy-saving operation and the no-load running current is small. It is especially suitable for the working condition of waiting for the rubber material to run at intervals in the rubber mixing process and realizes 10-25% energy-saving benefits.
