Abstract: SINCR C500 series inverter is applied to the mixing machine of a food factory in Tianjin with a power of 2.2 kw and 75kw. The mixing efficiency is high, energy saving and efficiency increase.

Keywords: SINCR inverter C500 inverter frequency conversion speed chopper

The frequency conversion speed mixing machine is a necessary equipment for food processing. It specializes in the equipment of meat puree and food mud. The mixing efficiency is high and delicate. The connective tissue in the meat can be destroyed by the blade rotating at a high speed by the chopper, and the protein having good water absorption and emulsifying property can be released, thereby improving the emulsification effect, elasticity and fineness of the meat product. At the same time, the utilization rate of raw meat is improved. Cabbage, leeks, and green onion chopping machines have good mixing effects for vegetables (celery, etc.), and are good assistants for meat and food processing plants such as sausages, quick-frozen dumplings, luncheon meats, and meatballs.

1. The structure and working principle of the chopping machine

Regardless of the size of the chopper and the high-speed type, the chopping machine with a cutter shaft running speed of 4000r/min or more is called a high-speed chopping machine. The higher the line speed of the knife set, the more the effect of the mashing emulsification. Well, the chopping machine below 4000r/min is called a common chopper. The operation process of the cutter shaft drive system of the common type chopping machine: first low speed, medium speed, and high speed.

In the process of entering the rotating rotary pot, the raw meat is uneven in weight, uneven and lumpy. Firstly, the low speed operation of the cutter shaft is used to achieve uniform stirring. This is the picture t0-t1 current curve has large fluctuations. The reason, when the load current gradually stabilizes as shown in t1-t2, that is, the agitation is completed. At this time, the high-power asynchronous motor (4 stages) is started to operate, the load current of the tool shaft is running, and there is an impulse current t2-t3 interval in a short time. After the passage, the attenuation tends to be smooth, and during the period of t3-t4, the resistance torque Constant, the mixing torque is smooth, and the pellets of the meat material are remarkably refined. At this time, the high-speed (2) operation of the cutter shaft is started, and the fine particles are further processed, that is, emulsified. From the interval of the picture t4-t5, we can see that in the short-term operation of the high-speed operation of the conversion cutter shaft, the working current of the mixer is stable in a constant torque region after t5, except for the inevitable inrush current at the start. Inside.

2. Application of frequency converter in chopping machine

With the awareness of social energy conservation and environmental protection and the needs of meat development varieties, ordinary chopping machines cannot meet market demand. At present, the high-speed choppers used in foreign countries are mostly closed-loop speed regulation methods for DC motors. The advantages are: large speed range, high output torque at high and low speed, stable rise and deceleration, small starting impulse current, easy regenerative braking, no major impact on the power grid; disadvantages are complicated control lines, large body, expensive, fault repair difficult.

In order to achieve high-speed operation of the chopping machine, we use the combination of frequency converter and variable frequency motor to meet the operational requirements. At present, there are many types of general-purpose inverters on the market, and the performance is continuously improved. The functions are continuously enriched and enhanced, and the quality is more and more guaranteed. The U/F controlled inverter has already realized the torque function, and it is constantly updated and improved. The high dynamic performance vector control universal frequency converter has high dynamic performance, and has a wide speed range, and the low frequency has a torque boosting function, also called a voltage compensation function.

The mixer is at the initial stage of low-speed agitation, and the load torque fluctuates greatly, accompanied by large current jitter. At this time, the inverter motor controlled by the inverter is the low-frequency operation state below the fundamental frequency, because the inverter has low-frequency torque. The lifting function and the anti-shock function ensure the output of the constant torque of the variable frequency motor, which can meet the torque requirement of the mixing machine at low speed. In high-speed emulsification, the motor runs above the fundamental frequency. Although the output torque decreases with the increase of the rotational speed, Figure 2 shows that the working in the constant power section, however, the load resistance torque has been significantly reduced and stabilized by the first two stages of operation. For the work above the fundamental frequency, the speed is increased, and the constant power output of the torque drop is just the load reduction. This coincidence gives us a main basis for selecting the inverter control mixer to operate at high speed. According to this basis, as long as the resistance torque of the mixing material at low speed stirring and the resistance torque during high speed emulsification are mastered, it is easy to purchase the corresponding variable frequency motor and the low speed compensated U/F according to these two important parameters. The general-purpose inverter of the control, with reasonable and reliable electrical control, is not difficult to complete the operation control of the speed regulation of the frequency converter for high-speed mixing.

3. Conclusion

We analyzed the function of the frequency converter and the operating characteristics of the variable frequency motor, which just used the conditions for controlling the operation of the high speed chopper. The inverter-controlled variable frequency motor has been operated on a high-speed chopper, passed the national appraisal, and obtained a patent certificate. It has been applied in meat processing companies. The high-speed chopper mixing machine with reasonable price, simple control and reliable performance has been facing the market, making up for the shortcomings of this field in China and meeting the needs of meat food manufacturers.