Shilin SF-G Inverter Application in Mixer

1 Mixer configuration and operation overview:
Mixing machinery is widely used in the production processes of chemical, pharmaceutical, food, aquaculture, plastics, and other industries. Mixing machinery is designed according to the requirements of the use of working conditions to consider a certain margin, and the mixer in the actual use of the process, then It is not necessary to work at the maximum speed. There is a lot of time to work in the non-full load state; the traditional mixers usually do not adjust or use mechanical speed; the mechanical speed regulation will increase the loss of the mixer and at the same time make the mixer work In the fluctuating state, the mixer equipment also works in the "big horse-drawn car" state, which is not economical.
The relationship between the power and speed (frequency) of the motor of the pump equipment in the frequency conversion speed regulation mode can be known: the energy-saving effect of the speed control method of the inverter is very high, which is better than any of the previous speed adjustment methods and can pass Energy saving recovers investment in a shorter period of time. Because the load of the pump is similar to that of the liquid mixer, by installing the frequency conversion speed-regulating energy-saving device on the mixer device, many problems existing in the use of the traditional mixer can be solved once and for all, and the investment can be recovered through frequency conversion and energy saving.

2 Modification of the original system operating conditions 1. The main motor star-angle decompression starting, but the current is still large when starting, will affect the stability of the power grid and other electrical equipment operating safety.
2. The main motor is running at industrial frequency. It is a non-economic operation and the energy is wasted.
3, the main motor frequency operation makes the mixer run a lot of noise.
4, the main motor frequency starting equipment impact, motor bearing wear, equipment maintenance work is tedious.

3 The mixer frequency conversion scheme is known from the working principle of the fluid transmission equipment mixer: the flow (air flow) of the mixer is proportional to the rotation speed; the pressure (head) of the mixer is proportional to the square of the rotation speed, and the shaft power of the mixer is equal to the product of flow and pressure. Therefore, the shaft power of the mixer is proportional to the third power of the rotation speed (that is, proportional to the third power of the power supply frequency). According to the above principle, the power of the mixer can be reduced more by reducing the rotation speed of the mixer.
If the power supply frequency is reduced from 50Hz to 40Hz, P40/P50=(40/50)3=0.512, that is, P40=0.512P50 (P is the motor shaft power).
The power consumption of the mixer is proportional to the third power of the rotation speed. That is, N=KN3 N: the power consumption of the mixer; n: the rotation speed when the mixer is running; K is the proportional coefficient. The design of the mixer is designed according to the industrial frequency operation, but except for the high speed, the flow rate during most of the time is small. Since the frequency converter uses the sensorless control, the speed of the mixer can be changed along with the change of the flow rate, and finally achieve energy saving. the goal of. Practice has proved that the use of variable frequency equipment can make the average running speed of the mixer lower than the power frequency rotation speed by 20%, thereby greatly reducing energy consumption, and the energy saving rate can reach 20%-40%.
Because the mixer is a typical square torque load type, its power (shaft power), torque (pressure), speed (air flow) satisfy the following relationship (similarity theorem):
Pressure = P axis = QH
Q'/Q=N'/N then Q'=QN'/N
P'/P=(N'/N)3 then P'=P(N'/N)3
Induction motor speed formula n=60f(1-s)/p
Where: N, Q, H, P - rated speed of the mixer, air flow, shaft power
N', Q', H', P' - speed, mixer speed, water, shaft power in a certain range to meet the production requirements under the premise of the speed can be adjusted to adjust the speed of stirring, in order to facilitate uniform Stir and do not change the working cycle. This characteristic shows that adjusting the speed of the mixer, changing the output of the motor, makes the stirring speed always meet the process requirements.
To sum up: use of variable frequency technology to change the motor speed to adjust the flow rate and speed changes used to replace the control of traditional power frequency circuit, can achieve significant energy savings

4 Shilin SF-G series inverter features

4.1 SF-G is marked with double specifications. If the capacity of the inverter is slightly insufficient, it can be switched from G mode to P mode, and the rated current of the inverter will be improved.
(Example) SF040-37K/30k-G, G mode rated current = 60A, P mode rated current = 73A

4.2 With sensorless control mode (P mode/G mode), (P=120%, Q=150%/1Hz), the starting torque is large (P=120%, Q=150%/1Hz), which can improve the low-speed running characteristics. Speed ​​adjustment capability under variable load is also improved, while higher starting torque can be obtained

4.3 open loop low speed high rated torque output, speed control up to 100:1

4.4 With the power frequency operation function (P.247~P.250), the inverter's abnormal tripping when switching operation is cancelled

4.5 Advanced Motor Automatic Tuning Work in Optimal Operation

4.6 Built-in RS-485 communication interface

4.7 Built-in PID regulator can set energy-saving operation mode

5 Advantages of Transformer Conversion Frequency Conversion Regulator

5.1 Mixer frequency conversion energy-saving device is open-loop regulation;

5.2 soft start / soft stop mode can reduce the starting impulse current;

5.3 Inverter with intelligent protection, when the fault can automatically stop;

5.4 Different speeds can be used depending on the process;

5.5 Energy conservation through variable frequency speed regulation: As the motor of the mixer operates in the variable frequency speed control mode, its power and its rotation speed are similar to those of the pump, that is, the operating power is proportional to the third power of the rotation speed (frequency), and the viscosity is high. The proportion will decline (usually between the second and third powers). Therefore, when using the inverter mode to adjust the speed, a very considerable saving rate will be obtained.

6 system performance after the transformation

6.1 Inverter control is adopted to achieve maximum energy saving under the conditions that meet the requirements for use.

6.2 Reduced vibration and noise and wear due to deceleration and soft launch, extended equipment maintenance cycle and service life, improved equipment MTBF (uniform failure repair time) values, and reduced the impact on the grid, improving the system's reliability.

6.3 The system has various protection measures, which greatly improve the system's operating rate and safety and reliability.

6.4 The frequency conversion speed control system and the power frequency control system can be set to interlock with each other without affecting the operation of the original system. In the case of inspection, maintenance or fault of the variable frequency speed control closed loop control system, the original power frequency control system can still operate normally.