Application of the most popular Zhongyuan frequenc

  • Detail

In recent years, with the rapid development of economy, the machine tool industry has also made a leap forward development, which is reflected in the wide application of new technologies and the obvious improvement of enterprise benefits. At present, the mainstream of consumption in the machine tool industry is CNC machine tools. From the domestic and foreign market demand for CNC machine tools, the future CNC machine tool market has the following characteristics: first, economic CNC machine tools are the mainstream products in the future. Second, adopting new technologies, reducing costs and improving product stability are the key to the survival of enterprises. Next, let's talk about the application of zydl frequency converter in the industry by using frequency conversion speed regulation in machine tool driving:

the spindle transmission characteristics of the original machine tool:

generally, the driving system of the machine tool is driven by the motor to drive the gearbox to drive and speed regulation. It has the following characteristics:

1 Overview of the original system

a load constant power property

when the gearbox changes speed, the change of torque is inversely proportional to the change of speed. If the loss of the gearbox is not included, it has the characteristics of constant power in the full power range

1) speed grade

the speed governing box has 8 speeds: 75, 120, 200, 300, 800, 1200, 15002000r/min

2) main rated parameters of the motor

rated capacity: 3.7kw

rated speed: 1440r/min

load characteristics: constant power

3) the control mode is to control the opening and closing of the four clutches by the eight positions of the handle combination, so as to obtain eight combinations of gears, so as to obtain the eighth gear speed

b. strong overload capacity at low speed

at low speed, the rated torque of the drive system after speed reduction by the gearbox will be much greater than the maximum working torque of the load, which has a strong overload capacity

II. Basic considerations when applying frequency converter speed regulation:

1. The adjustment range of frequency converter speed regulation is very wide. General general purpose frequency converters can realize the speed regulation of the surface without contact with the sample within the range of 0-400hz by adopting the sticky soft rubber grade

2 considering that the machine tool requires hard mechanical characteristics. It meets the requirements of frequency converter + ordinary motor (or variable frequency motor) transmission, and has the characteristics of hard mechanical characteristics. Generally, it can provide 150% load torque at low frequency

3. Considering that the machine tool needs to have strong overload capacity at low speed. The frequency converter can provide 150% overload protection (60s), which can meet the requirements of the equipment

4. After using frequency conversion speed regulation, the original complex mechanical driving mechanism such as gear box can be simplified, with high degree of automation, simple operation and convenient maintenance

5 the frequency converter has voltage (dc0-5v, dc0-10v) and current analog input interface, which can be well matched with the control signal of the numerical control system

Pay attention to the prominent parts of the machine)

the specific application of the three medium source inverter in this industry

Zhejiang Kanmen machine tool factory mainly produces all kinds of economical simple CNC machine tools. Due to the high damage rate of the electromagnetic clutch used for speed regulation, it is understood that the frequency conversion speed regulation system has the above advantages, so it uses medium source frequency converter to realize frequency conversion speed regulation. The details are as follows:

1. the system composition after transformation should be replaced:

a in this system, the frequency converter adopts external terminal control, and the DCV signal sent by the numerical control system is sent to the frequency converter through the an1-gnd terminal of the frequency converter to realize the control of the digital setting speed on the analog variable frequency output. The motor speed is controlled by the voltage signal output by the CNC system

b the forward and reverse operation of the motor is controlled by OP6, OP7 and cm terminals of the frequency converter

c various protection signals are controlled by the TCTA normally open contact of the frequency converter, which can realize overcurrent, overvoltage, overload, overheating, negative pressure, lack of equal protection

2 setting of relevant parameters:

according to the requirements of numerical control system and machine tool design, the setting of appropriate parameters can improve the performance of the original product:

af111, f808 is used to adjust the maximum speed of the motor

bf114, f115 is used to adjust the time required for the motor to reach the maximum speed

cf513, F502 is used to adjust the output torque of the motor at low speed. For the above parameter settings, The end user can make minor adjustments according to the actual needs of the site

3 comparison with the original performance after transformation

speed regulation range of machine tool: 0-400hz. The rating and upgrading of material testing machine of Jinan experimental machine factory are easy to be confused and adjusted (most machine tools work under 3000 rpm)

acceleration and deceleration time: 0.1-30s adjustable

processing speed: 100-3000r continuously controllable

protection function: perfect, And there is a fault display

overload capacity: 100% - 180% adjustable

4. Actual use effect of customers: under the actual processing speed, after repeated tests, it fully meets the design requirements and achieves satisfactory results. Now the product has been mass produced and put on the market in 2000

5 possible problems - low voltage caused converter protection

in March 2003, a batch of machine tools were sent to Ningbo (the customer used to produce pneumatic tool parts). Three months later, the customer called and said that 10 converters had fault protection (and only daytime jump protection). The company sent technicians to the site to find out the cause of the fault, and found that the voltage at the work site was very low - the input voltage was only ac310v (low working voltage during the day). The customer did not understand the protection principle of the frequency converter, but thought there was a problem with the machine tool, and the customer asked to replace the frequency converter. In response to this situation, the technician introduced the cause of fault protection in detail to the other party, and assisted the customer in purchasing the voltage stabilizing equipment. There was no problem after installation - the problem was perfectly solved. The perfect protection function of the frequency converter is verified again, and the problems that manufacturers should pay attention to when selling to customers are also reminded. This proves once again the feasibility and practicality of using frequency converters for simple CNC machine tools. I believe that more and more CNC manufacturers will recognize this problem - using frequency conversion transmission has high reliability, convenient operation, less investment, fast effect and high cost performance

Copyright © 2011 JIN SHI