I. Overview
With the rapid development of the automobile industry and the agricultural locomotive industry, the corresponding bearing manufacturing enterprises also have a large market space. While bringing profits to the enterprise, many bearing manufacturers have increasingly higher requirements on rolling mills. Frequency conversion energy-saving transformation has become the direction pursued by bearing manufacturers.
2. Working principle
The rolling mill is specially used to process bearing products. Its working principle is: cold cylindrical steel is heated to about 1000 degrees through an intermediate frequency heating furnace, and then enters the rolling mill transversely. At this time, the rolling mill has already changed the required molds, hot cylindrical steel It can be rolled into the required bearing after one round of die rolling. At present, the main motor of the rolling mill used by users is generally 37KW to 132KW, six levels, and a large gearbox with rollers. The speed ratio of the gearbox is generally above 100, and the speed of the roller is about 8rpm, which is heated by the intermediate frequency heating furnace. Cold steel columns generally take 10 seconds or 40 seconds to heat up to 1000 degrees. But now the manufacturer's usage is that the main motor does not stop, and the hot steel column is rolled when it comes. If the hot steel column does not come, the motor will idle with the roller, which causes a lot of waste. 3. System configuration The use of frequency conversion speed regulation technology in rolling mills to achieve energy-saving operation is a key promotion technology for energy conservation in my country, which is generally valued by the national government. Based on the principle of energy saving and consumption reduction, and simple control, based on the original system, it is recommended that each rolling mill be driven by a frequency converter. When the inverter is selected, it is generally larger than the motor power by one specification.
The retrofit program shuts down the main motor and goes through axial feed. Taking a mill with a main motor of 37KW as an example, the 6000 series 45KW inverter is used, the speed ratio of the reduction gearbox is 120:1, and the speed of the roll is 8rpm. Two detection switches were installed on site, one as a deceleration signal and one as an accurate stop signal. When the hot steel column comes, it will accelerate the rolling immediately. After the rolling is completed, it will be accurately stopped to zero, and then the axial feeding and rolling. , So repeatedly.
The original method of operation generally rolls a material roll and then idles 1 to 3 turns to roll the second material (the number of idle power turns is more), and the operation is fully manual operation; When it comes over, it will automatically roll, the material will stop when it is heated, and the operation is much simpler while saving energy.
3. The wiring diagram is as follows:
Four, system advantages
1: 6000 series general-purpose inverter is economical and reliable, and has rich control functions. It has the following advantages:
A. Multi-channel can define multi-function input and output terminals;
B. Various V/F curves are optional;
C. Restart function after instantaneous power failure;
D. Stable start, suitable for large inertia load speed regulation;
E. Wide voltage operation, allowable voltage fluctuation range: 304--456V;
F. Built-in advanced PID algorithm, easy to realize closed-loop automatic operation;
G.ALPHA's proprietary hardware speed tracking technology realizes impact-free speed tracking;
H. Built-in RS485 communication, support MODBUS-RTU communication protocol and so on.
2: Effect after transformation
A. The energy saving effect is obvious (the idle rotation of the roller is greatly reduced), and the power saving rate is 15-25%;
B. The use of frequency converter to control the motor realizes the soft start of the motor, prolongs the service life of the equipment, and avoids impact on the power grid;
C. It has automatic protection functions for overload, overvoltage, overcurrent, undervoltage and power shortage;
D. Improve the safety of equipment operation and simplify the operation of equipment.
With the rapid development of the automobile industry and the agricultural locomotive industry, the corresponding bearing manufacturing enterprises also have a large market space. While bringing profits to the enterprise, many bearing manufacturers have increasingly higher requirements on rolling mills. Frequency conversion energy-saving transformation has become the direction pursued by bearing manufacturers. With perfect vector algorithm and high reliability of products, our inverter can meet the needs of rolling mill transformation.