Application of FGI FD100 frequency inverter on grinding machines in the mechanical processing industry
1.Overview：
With the development of power electronic technology grinder, frequency inverter speed regulation technology grinder is becoming more and more popular, and the application of frequency inverter grinding machine in mechanical processing industry has received a good grinder effect. The frequency inverter grinder has stepless speed regulation, soft start, constant torque output maximum grinder meets the requirements of machining equipment for constant speed / constant torque grinder.
Standard machining used grinding machine, grinding wheel motor are according to the traditional start circuit operation. Motor start running according to the rated speed, due to the power grid voltage has a certain grinder, grinding wheel work-piece grinding load changes, will affect the motor grinder speed error, standard grinding motor starting circuit generally only a processing speed, it is difficult to adapt to different work-piece size grinder requires different grinder processing relative line speed, so that the processed work-piece grinder processing precision is difficult to ensure. Therefore, from the improvement of processing quality processing efficiency, energy saving and other aspects, the frequency inverter speed regulation technology applied to the grinder, can receive satisfactory grinder effect.
Mechanical processing industry grinding machine products, work-piece size is different, different processing accuracy. Compared with the grinder, the grinding wheel speed is different from the spindle grinder line speed. It is difficult to adjust the speed of the spindle grinder speed to meet the requirements of the work-piece grinder. In addition, due to the stress bending of the grinding machine generated by the shaft processing process, the grinding process will produce different torque, which changes the output speed / torque of the grinding wheel, and the corresponding grinder will produce vibration blade / burning lines, etc., and the grinding accuracy is difficult to ensure, resulting in low production efficiency and low quality rate.
According to the size of the shaft diameter, the main grinding wheel motor grinding speed is equal to the output grinding speed of the grinding wheel. The grinding force grinder size depends on the output torque of the grinding wheel motor grinder. In the high speed section of the grinding machine of the output speed of the grinding wheel, the diameter of the grinding machine is small with less grinding feed. When processing large diameter, the low speed section of the grinding wheel is large, and the grinding wheel is difficult to operate at constant torque / constant speed. The speed grinder changes such as blade grain / burn grain / machining accuracy. Frequency inverter speed regulating motor grinder stepless speed regulating, constant torque output can just make up for the above defects.
2.Implementation plans：
According to the characteristics of the system running grinder, considering the equipment investment cost, the vector inverter with automatic torque lifting function is selected. Taking FGI FD100 series frequency inverter as an example, 18.5KW/15KW grinder frequency inverter is selected according to the power of grinding wheel motor. Taking 15KW as an example, the rated voltage is 380V, the output current is 37A, the frequency control is 0-500 HZ, and the over load capacity is 120% / 60S. With automatic torque lifting function, flexible PWM control, can achieve lower noise operation, more than 10 section grinder speed control.
According to the analysis of the load characteristics of the front grinder, the high speed section is constant power, the low speed section is constant torque, and the load requires large torque and strong overload capacity at low speed. For the motor base frequency above, in order to ensure that the motor is not under pressure, constant voltage frequency conversion is adopted. According to the motor theory, when the voltage is constant and the frequency increases, the motor magnet decreases with the increase of the frequency grinder. when the motor current is the rated current, the maximum allowable output torque decreases and the allowable output power remains constant, which is considered as constant power speed regulation and suitable for constant power load. Below the base frequency, in order to ensure the constant magnetic flux at each pole of the motor, V / F= constant grinder variable voltage variable frequency speed regulation is adopted. When the current of the motor grinder is the rated current, the allowable output torque of the motor is unchanged, which belongs to the constant torque speed regulation and is suitable for constant torque load. However, when the speed is low, the internal resistance of the motor cannot be ignored. If V / F is still constant, the torque of the motor will be reduced, which cannot meet the load requirements of the low speed, and the grinder torque and overload capacity is strong. Therefore, the automatic compensation function of the frequency inverter grinder is adopted, and the grinder V / F curve is selected for correction.
3.Application advantage
FGI FD100 series frequency inverter machining industry grinding machine application, as a power grinder grinding machine grinding wheel main motor introduced frequency conversion speed regulation technology, in order to adapt to a variety of different shaft grinding machine grinding machine processing needs, improve the efficiency, improve the quality of shaft grinding machine processing, save energy. Combined with the actual application of the field grinder, the operator's response is more handy, the surface is smooth and the imaging degree is high, and the yield is greatly improved.
