Views: 0 Author: Site Editor Publish Time: 2023-07-12 Origin: Site
I. Brief Introduction of Fan and Water Pump
Fan is a customary abbreviation for gas compression and gas conveying machinery in China. The commonly mentioned fans include: ventilator and blower, which are machines that convert rotating mechanical energy into gas pressure energy and kinetic energy and convey gas out.
A water pump is a machine that transports or pressurizes liquid. It transfers the mechanical energy or other external energy of the prime mover to the liquid.
Increase the energy of liquid, which is mainly used to transport liquid, gas-liquid mixture and liquid containing suspended solids.
Fans and pumps are all fluid machines, and they are all square torque load devices, that is, their output power is proportional to the third power of the rotational speed, and the output torque is proportional to the square of the rotational speed.
In our country, most of the traditional fan pumps matched with all kinds of mechanical and electrical equipment have the phenomenon of big horse-drawn carts. In addition, due to the changes in production and technology, it is necessary to adjust the flow and pressure of fluid frequently, and many units still adopt the backward way of adjusting the opening of wind deflector or valve. This backward adjustment method not only wastes valuable energy, but also has poor adjustment accuracy, which is difficult to meet the requirements of modern industrial production and services, and the negative effects are very serious.
With the continuous improvement and development of frequency conversion technology in recent ten years. The performance of variable frequency speed regulation is becoming more and more perfect, and it has been widely used in AC speed regulation in different fields. It has brought considerable economic benefits to enterprises and promoted the automation of industrial production.
Second, the necessity of variable frequency control of fan and water pump
The traditional fan water pump adjusts the flow through the wind deflector or valve opening, which has a huge energy waste and energy-saving space. The following table shows the energy savings that can be brought by the use of supporting frequency converters when users have different flow requirements:
Because the fans and pumps are all square torque loads, there is the following proportional relationship:
Flow Q∞n speed;
Square of pressure t ∞ n speed;
Power p ∞ n cubic of rotational speed;
So the following table is converted:
traffic | pressure | rotation speed | frequency | shaft power | Power saving rate |
100% | 100% | 100% | 50 | 100% | 0% |
90% | 81% | 90% | 45 | 73% | 29% |
80% | 64% | 80% | 40 | 51% | 49% |
70% | 49% | 70% | 35 | 34% | 66% |
60% | 36% | 60% | 30 | 22% | 78% |
Calculated by using a 75kW fan with frequency converter:
Assuming that the comprehensive demand rate of fan air volume is 70%, it can be saved every year if it runs for 8 hours every day and 25 days every month.
The electricity fee shall be:
75*(1-34%)*8*25*12=118800kWh
The results show that the annual electricity saving is far greater than the price of a 75kW inverter, and the inverter can be recovered in a short time. Equipment investment.
Third, Shenzhen Laeg frequency converter is applied to the fan and water pump industry.
The LD350 series inverter adopts the new DSP chip of TI company supplemented by optimized vector control technology, and adds a motor.
Energy saving mode function:
Under light load condition, it can save 20~40% excitation current loss;
1. wide range voltage use design, 310V~460V;
2.Thickened three-proof paint technology has strong adaptability to harsh environments such as metal dust and corrosive gases;
3. VF control is selected as the control mode, and the inverter is built with simple PLC and 16-speed control, which can realize multi-functional logic control to meet the requirements of various complex working conditions.
4. Multi-directional protection of the whole machine enables the system to run safely.
