CNC machine tools require a wide range of speed control, high speed accuracy, good acceleration and deceleration performance, accurate positioning control, protection function, and fault self-diagnosis. In the developed countries, the AC spindle drive system has basically replaced the DC spindle drive system, forming a series of products, which basically covers a large part of the machine spindle drive capacity. In recent years, despite the rapid advancement of domestic CNC technology, due to unbalanced development, high-performance digital AC spindle drive systems rely mainly on imports, which are expensive and difficult to maintain. As soon as possible, the development of a series of products with high performance and low cost of localized AC spindle drive system to improve the performance of CNC machine tools and reduce costs is an important issue to be solved. To this end, we have developed a series of 9 varieties of digital slip frequency vector control AC servo system, the main circuit components using IPM intelligent power module, suitable for CNC machine tool spindle drive. The running results show that the system achieves high-precision speed regulation and positioning requirements, and has good dynamic and static performance. The basic principle of the spindle drive system: The working characteristics of the spindle motor In the actual machining process of the machine tool, a wide range of speed regulation is required. Therefore, the spindle motor must work according to the characteristic curve shown in Figure 1: the constant torque should be satisfied below the base speed. It is required that the base speed should meet the constant power requirement. Basic Principles of Control System Spindle Drive Unit Control Strategy: In order to achieve high-precision speed adjustment and positioning requirements during spindle tool change, speed closed-loop flux vector control is used for control. The vector control technology uses the coordinate transformation method to decompose the AC motor stator current into two components according to the dynamic mathematical model of the AC motor: one is used to generate the excitation component M of the rotor flux, and the other is used to generate the electromagnetic torque. Torque component i to achieve decoupling control. At this time, the electromagnetic torque of the motor is: that is, it has a similar torque equation as the DC machine. In the case of decoupling control, the high-speed speed regulation characteristics equivalent to the DC speed regulation can be obtained by separately controlling and realizing the speed control of a similar DC motor. (Finish)
The Compressed Oxygen Self-Rescuer is also called the Compressed Oxygen Self-rescuer isolation type, oxygen source on the high-pressure compressed oxygen reusable self-help escape equipment, mainly in the coal mine or poisonous and harmful gas in the working environment of normal atmospheric pressure highlight and anoxia suffocate disasters.The human respiratory system is isolated from the outside world, which can be used for emergency personnel to save themselves quickly.It is light in weight, small in size, comfortable in breathing and easy to carry.According to the protection time there are 15, 30, 45min several specifications.
Compressed Oxygen Self-rescuer
Compressed Oxygen Self-Rescuer,Rescue Breathing Apparatus,Isolated Compressed Oxygen Self-Rescuer,Portable Compressed Oxygen Self-Rescuer
Jining Dongda Electromechanical Co.,Ltd. , http://www.coal-mine-equipment.com