light industry

1. With the development of power electronic technology, the frequency conversion speed control technology is becoming more and more popular, and the application of inverter in the machining industry has received a good effect. Frequency converter grinding machine stepless speed regulation, soft start, constant torque output maximum grinding machine to meet the mechanical processing equipment on the constant speed / constant torque grinding machine requirements
The grinding machine is used in the standard machining process, and the grinding wheel motor is operated by the traditional starting circuit. Motor start according to the rated speed operation, due to the voltage fluctuation are grinder, grinding wheel grinding machine workpiece friction load changing grinder, will affect the motor grinder speed error and standard grinding wheel motor starting circuit general only a processing speed, it is difficult to adapt to different workpiece size grinder requirements of different grinding processing relative linear velocity, so that the processing of grinding workpiece precision is difficult to guarantee. Therefore, in order to improve the processing efficiency, save energy and so on, the variable frequency speed control technology is applied to the grinding machine, which can be satisfied with the grinding effect.

2, grinding machine load characteristics:
Mechanical processing industry grinding machine grinder product variety, the size of the workpiece is different, require different processing accuracy. The grinding wheel speed of the grinding wheel is different from the speed of the main shaft grinding machine, and the speed of the grinding machine can be adjusted to the ideal state. Because the shaft machining process by generating grinding stress bending, grinding process will produce different wheel grinder torque, it leads to different grinding wheel output speed / torque changes, the corresponding grinder will produce vibration knife marks / burn paste pattern etc., grinding accuracy is difficult to guarantee, resulting in low production efficiency, low rate of products.
According to different grinding shaft diameter size grinder, grinding wheel motor speed is equal to the main output speed grinder grinding wheel grinding machine. The size of the grinding force is determined by the output torque of the grinding wheel motor. Driven rotating the workpiece spindle motor grinder high-speed segment, relative to the speed of grinding wheel output unchanged, the processing of grinding workpiece diameter is small, less feed grinding; machining large diameter long shaft workpiece, workpiece rotary grinder motor speed, large amount of feed of the grinding wheel, the grinding force becomes larger, motor is difficult to constant torque / constant speed operation. The change of the speed grinder has produced the change of grinding machine such as the vibration knife pattern / burning paste texture / machining precision. Variable frequency variable speed motor grinding machine stepless speed regulation, constant torque output just can make up for the above defects.

3, system design and design of the grinding machine:
Grinding grinding wheel balance grinder to improve the accuracy: the motor rated speed on the operation, in order to reduce the high speed grinder vibration, should improve the motor rotor grinding wheel grinder dynamic balance, and to be corrected.
Low speed grinder cooling: due to the electric motor for self cooling fan cooling, slow cooling conditions worse, while the load torque is big, motor temperature will increase, so the lowest speed grinder set to motor surface temperature does not exceed the permissible value basis.

4, grinding machine inverter selection:
According to the characteristics of grinder system operation, considering meet machining requirements, equipment investment cost point of view, selection of Shenzhen City Yi Chong Fei Electric Co., Ltd. is the production of ECF500 series vector inverter, its has the following characteristics:
1) using the latest generation of TI high speed motor control dedicated DSP, and innovative use of the three nuclear processing technology platform. Ultra high speed operation to ensure the complete implementation of complex vector computing.
2) a new generation of non PG vector control, the use of advanced motor model algorithm, so that open loop torque control to achieve the closed-loop algorithm. Torque response 10ms, steady state accuracy < =5%. Speed ratio of up to 1:200, steady-state speed accuracy of 0.2%. 0.5Hz can output 180% rated torque.
3) PG vector control. Closed loop torque control. On line switching of torque and speed control. Zero servo control of frequency converter. 0Hz can output 180% of the rated torque, stable speed accuracy of up to 0.02%, the dynamic response time is less than 10ms.
4) standard products all the three proofing lacquer processing, and on occasion of the excessive moisture or dust, but also provide protective reinforcing treatment measures, in order to meet the requirements in more harsh environment for long-term stable operation.
5) the full range of over current, over voltage, overload suppression and stall prevention function. Perfect self checking function, wide voltage range design. The first use of a new generation of Infineon IGBT module, higher reliability.
6) 15 speed control, simple PLC realization of time, speed and orientation of the multi function control logic, a variety of flexible control mode to meet the various complex conditions.

 

5, system and the speed of the grinding machine:
Considering the inertia of the grinding wheel, the soft start time is set to 10S, the stop time is set to 15S, according to the different type of grinding wheel starting torque can be adjusted between 50%-80%. System speed through the external can be adjustable potentiometer to adjust the frequency, according to the diameter workpiece speed adjustment according to different grinding, high-speed motor the limitation of the mechanical strength of the grinder / noise / vibration grinding machine, the highest frequency of motor set for 60Hz; considering the low speed motor cooling effect factors such as low, the lowest frequency set for 35HZ.

 

6, the end of the language
Using ECF500 vector frequency converter with high performance, low frequency torque, speed stability, grinder and strong control; circuit plate with a new and three defenses, adapt to the grinder in hot and humid environment, inverter fault rate is low.