light industry

First, the foreword
The outer cylindrical grinding machine used for standard machining, the grinding wheel motor is operated by the traditional starting circuit. Motor start according to the rated speed operation, due to the grid voltage fluctuation, the grinding wheel and the workpiece in the friction load constant change, will affect the motor speed error, standard grinding wheel motor starting circuit generally only a processing speed, it is difficult to adapt to the requirements of different workpiece size different processing relative linear velocity, so that the processing of the workpiece machining precision is difficult to guarantee. Therefore, in order to improve the processing quality and processing efficiency, save energy and so on, the variable frequency speed control technology is applied to the outer cylindrical grinder, which can be satisfied with the results.
There are many kinds of products in the machine processing industry, the size of the workpiece is different, and the processing precision is different. Relative to the requirements of the spindle speed of the spindle speed is different from the simple adjustment of the spindle speed to meet the processing speed of the workpiece is difficult to adjust to the ideal state. Due to the stress of shaft in the process of bending in the grinding process will produce different feed of the grinding wheel torque, so bring wheel output speed / different torque changes, the corresponding will produce vibration knife marks / burn paste pattern etc., the grinding accuracy is difficult to guarantee, resulting in low production efficiency, low rate of products.
With the development of power electronic technology, frequency control technology is becoming more and more popular in the field of mechanical processing industry, the application of frequency converter has received very good results. Frequency converter stepless speed regulation, soft start, constant torque output greatly meet the mechanical processing equipment on the constant speed / constant torque requirements.

 

Two, the load characteristics of cylindrical grinding machine
According to the different axial diameter of the grinding wheel, the main motor speed is equal to the output speed of the grinding wheel. The size of the grinding force depends on the output torque of the grinding wheel motor. In driving the rotating spindle motor in high speed, constant relative to output speed of the grinding wheel, the processed workpiece diameter small, less feed grinding; machining large diameter long shaft workpiece, workpiece rotating motor at low speed, large amount of feed of the grinding wheel, the grinding force also the motor is very difficult in constant torque and constant speed. The change of speed is produced, such as the change of the pattern of the vibrating knife, the burning pattern and the processing precision. Variable frequency speed regulation motor stepless speed regulation, constant torque output just can make up for the above defects.

Three, the choice of frequency converter
According to the characteristics of the system operation, meet the machining cylindrical grinder requirements and the equipment investment cost considerations, we use with automatic torque boost function of Yi Chong Fei vector inverter ECF500 series. According to the different selection of different power power wheel motor inverter, 10kW, for example, rated voltage 380V, output current 17.5a, frequency control 0.50 ~ 400Hz, speed control of 0.1%, load capacity 150%/60S. With automatic torque to enhance the function of low speed torque, can achieve lower noise operation, the 16 section of the speed control. ECF500 series three paint, more resistant to oil and gas environment.

 

Four, system start and speed regulation
The starting circuit of the main grinding wheel motor of the outer cylindrical grinder adopts the star delta conversion starting circuit. Replacing the original circuit with frequency converter, using the normally open contact of the original contactor to control the operation of the inverter, considering the inertia of the grinding wheel, the frequency converter soft start time is set to 10S, the stop time is set to 15S. The system speed can be adjusted by the potentiometer on the panel. According to the appropriate adjustment of different diameter of workpiece, due to the limit of the motor with high mechanical strength / noise / vibration and other factors, the maximum frequency of inverter set for 60.00Hz; because of the low speed motor cooling effect is poor, consider rotating shift factors and actual size of workpiece, the lowest frequency set for 20.00Hz.

 

Five, the end of the language
Yi a flying development ECF500 series inverter listed is successfully applied in the grinding machine is Yi Chong Fei technology for many years of development experience and field experience in the application of the combination of the results, proving once again that Yi Chong Fei science and technology in the converter industry advantage.