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1、变频器恒压供水教学演示系统设计The design of.Txt31 inverter constant pressure water supply system of teaching demonstration under the rock cliffs on the grass to teach us strong, wild lily to teach us, mountain pine teach us hard rain, cold nitens teach us to meet the snow. This article is contributed by shinyqb123
2、Pdf documents may experience poor browsing on the WAP side. It is recommended that you first select TXT, or download the source file to the local view.Volume second, phase thirty-first, February 2010Journal of Tonghua Normal University, JOURNAL, OF, TONGHUA, TEACHERS, COLLEGENo. 2. Vol 31 Feb. 2010D
3、esign of constant pressure water supply teaching demonstration system for frequency converterWang Lizhong, Wang Guangde, Liu Hongbo, Han, Meng Zhaohui, Cong, Qiang Lin(School of information technology, Jilin Normal University, Jilin Siping 136000)Abstract: in order to train students occupation skill
4、, based on the development status and characteristics of the automatic control system of water supply and the analysis and comparison of domestic and foreign, combined with the city water supply is to shape, designed based on variable frequency speed regulating technology in constant pressure water
5、supply control system. This system uses the relay control technology, frequency conversion technology and the automatic control technology to realize the constant pressure water supply parameters setting, to ensure the water supply system to maintain the best operating conditions, and cultivate the
6、students ability to design and system of professional interest in learning. Key words: constant pressure water supply; frequency conversion; classification number: T M301. in such 2 document code: A article number: 1008 - 7974 (2010) 02 - 0023 - 03 project development plan of science and technology
7、of Jilin province (20050523); Jilin Provincial Department of education research project (Kyrgyzstan UNESCO Zi 2003 No. twenty-fifth); Jilin Provincial Department of Education (education science research project of Ji Zi 2004 No. fifty-fourth); Siping science and Technology Bureau project (four Kehe
8、No. 20030017th). Received: 2009 - 10 - 28 Author: Wang Lizhong (1970 -), male, Jilin Gongzhuling, master, associate professor of Jilin Normal University Institute of information technology.The traditional way of water supply constant speed pump pressurized water supply, water supply, water tower hig
9、h pressure water tank. The disadvantages of low efficiency and poor reliability, automation degree is not high the traditional water supply mode in different degree, it is difficult to adapt to the current water supply in peoples life needs. The current water supply method is toward high efficiency
10、and energy saving, automatic reliable direction. So the development of VVVF constant pressure water supply system automatically, people pay more and more attention. In order to meet the water quality requirements, reduce energy consumption, to achieve automatic, stable and reliable water supply, the
11、 use of variable frequency constant pressure water supply with automatic constant pressure operation, automatic operation, remote control and manual control functions. According to the students occupation skill training, installation design students under the guidance of teachers and debugging of co
12、nstant frequency The pressure water supply system can train the students comprehensive design ability and engineering consciousness. As a teaching demonstration system, they can also stimulate the students interest in professional knowledge by demonstrating the effect, and understand the application
13、 of frequency converterThe system based on I converter with built-in P module parameters preset, D by hydraulic pressure gauge remote feedback closed-loop system is formed according to the change of water use, continuous adjustment to achieve constant pressure water supply pump used in full flow ran
14、ge.Constitution of 1 variable frequency constant pressure water supply demonstration system1 - 2The utility model can prolong the service life of the water pump, and can save electric energy, water saving, reliable operation and flexible control when regulating the flow of the water pumpFig. 1 block
15、 diagram of systemIn the constant pressure water supply control system of inverter inverter resistant production company, the main role is to change the motor speed according to the frequency, pressure changes. The controller uses the JY2000 type, the main role is to set and display the pressure siz
16、e and changes. The remote pressure gauge to monitor the actual pressure. Mechanical and electrical control part is to control the operation of the motor core circuit. Conversion and display part is frequency and frequency conversion and display state. The water level detector for detecting the water
17、 level is higher than the set value or below the set value, the status signal to control the motor running.2 control system electrical diagram and working principleAccording to the teaching characteristics and practice ability of electronic technology professional frequency control principle, the de
18、sign is simple and practical teaching system. The constant pressure water supply system by the inverter, remote pressure gauge, electric motor, controller, AC contactor, thermal relay, automatic air switch, switch and display element, box and auxiliary parts etc. the transfer of water into 3 - 4. Th
19、e system structure shown in Figure 1. Soft start constant pressure water supply system can realize the pump, thereby reducing the impact of pump startWhen the system starts the first closed air switch, to achieve frequency position switch, three-phase alternating current to the inverter through swit
20、ch to AC contactor thermal relay and load, the inverter output frequency conversion drive motor start running, the reservoir water is pumped to the water in the pool, in the? 23?China Academic Journal Electronic Publishing House. All rights reserved.Http:/The use of remote pressure gauge pressure de
21、tecting changes in the process, due to the smaller water pressure does not reach the set value, the frequency of transducer on the rise, the motor speed is increased, the water from the reservoir continuously pumped to the pool. The water pressure on the water tank controller can withstand the press
22、ure value (assuming 5 pressure), when reaching the set pressure the frequency of the inverter, that constant pressure, constant motor speed fixed. If the detected pressure is greater than the set value, the system does not start, start the system when the pipeline pressure is less than the set value
23、, if the variable frequency motor fault, the frequency motor can start to guarantee water supply. The practical application in order to ensure the quality of water supply, water consumption in large that can increase the motor and frequency inverter. In the constant pressure water supply demonstrati
24、on system can be based on the size of the water can automatically adjust the motor for the user The purpose of constant pressure water supply is that the pump motor is the output link of the system,Its speed is controlled by a frequency converter, realizing the constant pressure variable water press
25、ure control. The inverter speed control of pump and signal receiving P I D control system, a pressure sensor for detecting pipe outlet pressure, the signal is sent to the P I controller, P control D I converter by adjusting D controller to control the frequency of pump motor speed, to realize closed
26、-loop control. The electric control principle shown in Figure 2. The pressure and pressure detection value of a given value gap is large, the change of the output signal is greater. Once the pipeline pressure reaches the set value, the output control signal is constant, stable operation of system.5T
27、ypes of output characteristics of pump not only depends on the pump, but also curve with the resistance characteristics of the water supply system is different. The characteristic formula of centrifugal pump is as follows: (1) P = kHQ / type, P pump power (kW); Q for the use of operating point of wa
28、ter pump (3 M / S; H) for the use of operating point of the head (m); K lost 3 medium (kg /m); constant ETA for pump efficiency in the use of operating point (%). The characteristic curve of centrifugal pump as shown in Figure 3.Figure 3 H - Q curve of centrifugal water pumpFlow Q and speed n once s
29、quare is proportional to; lift H and speed n square is proportional to; pump power P and speed n cubic is proportional to the head H and flow Q relationship curve, as shown in 4Figure 4 water supply network H - Q curveIn Figure 5, D pump rated operating point is the intersection curve and Nn curve o
30、f R1 pipeline resistance of the pump. The pump control valve using the traditional, due to reduced traffic, close a small valve, the valve friction resistance becomes large, the resistance curve shifted from R1 to R 1, Yang Cheng from H0 to H1, from Q n to Q flow rate decreases 1, the operating poin
31、t of transfer from D to A.Fig. 2 Schematic diagram of electrical controlAdvantages of 3 variable frequency constant pressure water supply systemWith variable speed to achieve constant pressure water supply, and the traditional regulating valve to achieve constant pressure water supply compared advan
32、tages are: (1) start balance, the starting current may be restricted within specified current, so as to avoid the impact on the grid when starting. (2) because the average rotational speed of pump is reduced, thereby prolonging the pump and valve etc. the use of life. (3) can eliminate water hammer
33、effect when starting and stopping. The main function of the preset, the highest frequency in the rated frequency of the motor is the highest frequency of inverter. (4) electric energy saving. The pump load torque and speed is proportional to the output power and speed, 3. According to the required f
34、low is proportional to the frequency converter automatically adjust the speed, so that it can save electricity.? 24?The China Academic Journal Electronic Publishing House. All rights reserved. http:/Fig. 5 H - Q curve of water supply flow changeThe speed control of the water pump, the valve does not
35、 switch changes, so the resistance curve R1 unchanged. In order to change the flow rate, you need to change the speed of the pumpIf the speed is reduced from Nn to N1, the characteristic curve is shifted from N n to N 1. At this point, the operating point is shifted from D to C, YangFrom 0 down to H
36、 H 3, n traffic from Q reduced to Q 1. according to the formula (1) for an operation, the pump power consumption in A for PA = kH1 Q 1 / C pump efficiency, power consumption is Pc = Q / kH3 is 1, the difference between the two is: P = PA - PC = K (H3 - H1) Q / 1. That is to say, with the valve to co
37、ntrol the pump flow, there is a P power is wasted, and the loss of the valve with Guan Xiaoer. This increased frequency constant pressure water supply and energy saving. (5) to save water. For constant pressure water supply with inverter. To maintain a constant pressure pipeline, pipe can prevent co
38、llapse phenomenon, reduce the run, run, drip, etc., so as to save water. (6) to extend the service life of the system. By using special inverter constant pressure water supply water supply, the system can keep constant pressure, does not appear the phenomenon of excessive pressure, The pressure of p
39、ipeline has been maintained at a reasonable range, prolong the equipment replacement cycle, reduce maintenance investment, and avoid the pipeline crack accident. The design of the system in both practical and design significance and matters needing attention 4 control system, through the design and
40、demonstration to make students understand the process control system design, master the working principle of the converter, learn the wiring method of relay control system, for theReference:6Engineering design ability and the occupation skills high students are good. The factors should be considered
41、 in the design of the system are: (1) pipeline pressure control points selection. In order to reduce the cost and increase the reliability of the pump constant pressure mode, monitoring water pump caused by surplus lift but only by the change of water, to select the appropriate hydraulic control poi
42、nt, lift and pipe resistance curve is better after the pump speed control with, in order to obtain the best energy-saving effect. (2) the anti interference problem. In order to ensure the reliable operation of the system, should pay attention to take measures of anti interference in electrical conne
43、ction: if the signal line selection, power line and twisted pair the signal line with shield layout is not parallel, weak strong separate grounding problem with one point grounding mode. This paper analyzes the 5 adopt frequency conversion speed to achieve constant pressure water supply system The w
44、orking principle and system design method, through debugging can achieve the purpose of constant pressure water supply. The design of the system, to make the students master the design method of the system design principle and frequency control system. According to the actual situation but also the
45、system is extended by computer or PLC and transducer combination, realize intelligent control, such as the increase of Water Leakage alarm lamp and other functions, has good application value.1 Zhang Jinrong. Inverter in constant pressure water supply system in the application of J the application o
46、f frequency conversion technology, 2008 (6). 2 Wu Zhongzhi, Wu Jialin. Application of manual M. Beijing: Mechanical Industry Press, 2002. 3 Wang Zhaoyi. Application and training of inverter guide M. Beijing: Higher Education Press, 2005. 4 Zhang Jinrong.Fan energy-saving inverter application example
47、 J fan technology, 2001 (2). 5 Chen Jingwen frequency constant pressure water supply control system in high-rise building design J Chinese water supply and drainage, 2007 (24). 6 Li Zhirong, Anji show. Frequency adjustment of constant pressure water supply system J electric gas the times, 1999 (12).
48、(editor in chief: Wang Qian)(up to nineteenth pages) the charge on E1 and 2 can always be neutralized, and the electrical E T between the discharge balls T1 and 2 is neutralizedThe subsection correspondence analysis method can explain the principle of electrostatic induction motor simply and clearly
49、Pressure can not generate electricity. This shows that, compared with the commonly used analysis diagram, the use of plansReference:1 Zhang Dexin. Electrostatic induction electric motor principle J teaching instrument and experiment, 2007 (12). 2 Cui Feng. Induction motor reversal anelectric reason J on the physics experiment, 20