Abstract: Since the advent of universal variable frequency speed controller, frequency conversion speed regulation technology has been widely used in various fields. The advantages of frequency converter such as energy saving, safety, high quality and so on have been greatly developed in practical application, with With the rapid development of electronic technology, the function of the frequency converter is getting stronger and stronger. In particular, it makes full use of the built-in PID adjustment function of the inverter, which is of great significance to the rational design of the frequency converter and the normal production. Keywords: 55KW circulating cooling water pump system transformation Abstract: Since the advent of universal variable frequency speed controller, frequency control technology has been widely used in all fields, frequency converter with energy saving, safety, high quality and other advantages, at In actual application, great progress has been made. With the rapid development of electronic technology, the function of the frequency converter is getting stronger and stronger. In particular, the PID adjustment function built into the inverter is fully utilized, Ensure normal production and so has a very important significance. Keyword: 55KW circulating cooling water pump system transformation In the past, my company's circulating cooling water system uses two circulating pumps (one with a backup) to the constant speed pump water supply, water pressure fluctuations under normal circumstances, Energy loss, in the event of large plant water pressure pipe network will rapidly decline, while the plant to stop or reduce the water consumption, pipe network pressure will rise rapidly, in fact, indirect flow changes lead to pressure pipe network caused by circulating pump Of the output power loss, the outlet pressure of the circulating pump instability caused by changes in the operating point of the circulating pump, so that the efficiency of the circulating pump group itself worse, virtually increase the consumption of electrical energy and equipment, mechanical wear and tear, easily lead to equipment The failure rate increases, and in order to ensure normal production, to the workshop expected cooling effect, usually the pressure after the circulating pump to maintain high, so the relative constant flow pump circulating water pump water flow at the end of pipe network pressure at the end of water Traffic hour pipe network pressure is high; company on the use of circulating water workshop no specific what provisions and constraints, when There is no need to recirculate the water in the workshop, and the circulating pump is on. Sometimes, the circulating water pump is not able to absorb the water due to the water level of the recirculating water tank, and the circulating pump group is wasted power and energy in the no-load operation Accelerate the mechanical wear of the pump group; on the other hand, the start-up mode of the dragging motor of the circulating pump adopts the instantaneous start-up of the star-delta step-down, the shock wave at start-up causes instability of the power grid and the mechanical performance of the circulating pump group is impaired. In view of the above intention to use frequency conversion speed control closed-loop control. Since the advent of the universal frequency converter, frequency control technology has been widely used in all fields, the frequency converter with energy saving, safety, high quality and other advantages, in the practical application has been greatly developed, with the electronic With the rapid development of technology, the function of frequency converter is also getting stronger and stronger. In particular, it makes full use of the built-in PID regulation function of inverter, which is of great significance to the rational design of frequency control equipment and normal production. The company's circulating pump water supply system through the inverter to change the water pump output capacity to adapt to the flow of the workshop needs, when the circulating pump speed changes, with the change of head characteristics, while the tube resistance characteristics are unchanged, the regulation Pipe network pressure flow. Because of the different time periods, the workshop water consumption is very large, in order to save energy, in order to use more and more to send more and less to use less open to send less principle, it usually requires "1 control X" switch. If the water supply is insufficient, the circulating pump speed is automatically increased to increase the pressure of the pump group outlet or to start the pump group 2 for frequency conversion control. On the contrary, when the workshop water consumption is reduced, the pump group No. 2 should be stopped to exit the work first, Pump frequency control system water supply. Inverter has a built-in PID adjustment operation function, so that the collected pressure signal (DC4-20mA) after the PID adjustment comparison and processing to get a new frequency of the given signal output (DC4-20mA), determine the inverter output frequency Of the size of the circulating pump to change the speed of the pump to achieve a constant pressure pipe network constitutes a closed loop set value control system can be automatically adjusted according to need to achieve real-time regulation of pipe network pressure steady, to avoid fluctuations in water pressure flow caused Of the impact of loss; a reasonable set of PID parameter values ​​can greatly reduce the system water pressure over the water supply pipe network caused by the power loss, saving energy and reduce mechanical wear and tear. In addition, the transitional setting of the circulating pump motor starting process by the frequency converter makes the starting current of the pump group gently increase and continuously start running, which avoids the impact of the high current on the power grid caused by the conventional rapid starting motor and the generated mechanical Impact; thus effectively reduce the wear of bearings and other wearing parts, generally reduce the mechanical stress, with power and extend the life of the motor, pump group effect. In addition, the water level of the circulating water tank and the operation of the fan on the cooling pedal are interlocked with the closed-loop control system of the variable frequency speed regulation of the circulating pump set. According to the pool water level decided to boot, when the pool water level over the bottom can be automatically opened to supplement the inlet valve to the pool water, until it reaches the predetermined level. This ensures the normal operation of the entire system controllability. Schematic drawings of the program: Schematic diagram of the control system electrical main wiring Control system Electrical frequency converter Internal wiring diagram (general fan pump) No. Material Name Model Specifications Unit Quantity Price Amount 1 Circuit Breaker CM1-225M / 33002 160A only 3 650.00 1950.00 2 AC contactor CJ20-160A 380V only 4 380.00 1520.00 3 Current transformer BH-0.66 150/5 only 2 50.00 100.00 4 ammeter 6L2-A 150/5 only 2 40.00 80.00 5 voltmeter 6L2-V 0-450V only 1 40.00 6 Signal AD11-25 / 40 only 5 10.00 50.00 7 Control button LAY3 only 6 15.00 90.00 8 Universal relay HH54P only 4 10.00 40.00 9 Level controller YJ-712 only 1 40.00 10 Pressure transmitter HBY-2000 sets 1 3000.00 11 Frequency Converter VF-55KW Taiwan 1 18000-35000.00 12 Box table 1 1000.00 13 The main line approved 1 200.00 14 Accessories fee approved 1 200.00 15 Notes 16 Total cost 26310.00 ~ 43310.00 yuan Frequency governor in the past my company's cycle Cooling water system uses two circulating pumps (one with one prepared) to a constant speed pump water supply, water pressure fluctuations under normal circumstances, large energy loss , In the event of a large workshop water pressure pipe network will rapidly decline, while the plant to stop or reduce water consumption, pipe network pressure will rise rapidly, in fact, indirect flow changes lead to pipe network pressure changes caused by circulating pump output power Loss, instability of the outlet pressure of the circulating pump causes the working point of the circulating pump to change, which makes the efficiency of the circulating pump group worse, virtually increases the consumption of electric energy and the mechanical wear of the equipment, which may easily cause the equipment failure rate In order to ensure the normal production and achieve the expected cooling effect in the workshop, usually after the circulating pump pressure remains too high, so the constant flow pump circulating water pump network with large water flow when the pressure at the end of pipe network, water flow hour tube Network pressure high status; company on the use of recycled water in the workshop there is no specific what the rules and constraints, sometimes there is no need to recycle the workshop of circulating water pump is open; and sometimes because of circulating water tank over the bottom of the pump Group did not know the water does not absorb, circulating pump group was running at no load both waste of energy and accelerate the pump mechanical grinding ; On the other hand circulating pump drives the motor start-up mode with a star - triangle buck instant start, when the shock wave caused by the start of instability and damage to the mechanical properties of the circulation pump assembly grid. In view of the above intention to use frequency conversion speed control closed-loop control. Since the advent of the universal frequency converter, frequency control technology has been widely used in various fields, the frequency converter with energy saving, safety, high quality and other advantages, in the practical application has been greatly developed, with the electronic With the rapid development of technology, the function of frequency converter is also getting stronger and stronger. In particular, it makes full use of the built-in PID regulation function of inverter, which is of great significance to the rational design of frequency control equipment and normal production. The company's circulating pump water supply system through the inverter to change the water pump output capacity to adapt to the flow of the workshop needs, when the circulating pump speed changes, with the change of head characteristics, while the tube resistance characteristics are unchanged, the regulation Pipe network pressure flow. Because of the different time periods, the workshop water consumption is very large, in order to save energy, in order to use more and more to send more and less to use less open to send less principle, it usually requires "1 control X" switch. If the water supply is insufficient, the circulating pump speed is automatically increased to increase the pressure of the pump group outlet or to start the pump group 2 for frequency conversion control. On the contrary, when the workshop water consumption is reduced, the pump group No. 2 should be stopped to exit the work first, Pump frequency control system water supply. Inverter has a built-in PID adjustment operation function, so that the collected pressure signal (DC4-20mA) after the PID adjustment comparison and processing to get a new frequency of the given signal output (DC4-20mA), determine the inverter output frequency Of the size of the circulating pump to change the speed of the pump to achieve a constant pressure pipe network constitutes a closed loop set value control system can be automatically adjusted according to need to achieve real-time regulation of pipe network pressure steady, to avoid fluctuations in water pressure flow caused Of the impact of loss; a reasonable set of PID parameter values ​​can greatly reduce the system water pressure over the water supply pipe network caused by the power loss, saving energy and reduce mechanical wear and tear. In addition, the transitional setting of the circulating pump motor starting process by the frequency converter makes the starting current of the pump group gently increase and continuously start running, which avoids the impact of the high current on the power grid caused by the conventional rapid starting motor and the generated mechanical Impact; thus effectively reduce the wear of bearings and other wearing parts, generally reduce the mechanical stress, with power and extend the life of the motor, pump group effect. In addition, the water level of the circulating water tank and the operation of the fan on the cooling pedal are interlocked with the closed-loop control system of the variable frequency speed regulation of the circulating pump set. According to the pool water level decided to boot, when the pool water level over the bottom can be automatically opened to supplement the inlet valve to the pool water, until it reaches the predetermined level. This ensures the normal operation of the entire system controllability. Schematic drawings of the program: Schematic diagram of the control system electrical main wiring Control system Electrical frequency converter Internal wiring diagram (general fan pump) No. Material Name Model Specifications Unit Quantity Price Amount 1 Circuit Breaker CM1-225M / 33002 160A only 3 650.00 1950.00 2 AC contactor CJ20-160A 380V only 4 380.00 1520.00 3 Current transformer BH-0.66 150/5 only 2 50.00 100.00 4 ammeter 6L2-A 150/5 only 2 40.00 80.00 5 voltmeter 6L2-V 0-450V only 1 40.00 6 Signal AD11-25 / 40 only 5 10.00 50.00 7 Control button LAY3 only 6 15.00 90.00 8 Universal relay HH54P only 4 10.00 40.00 9 Level controller YJ-712 only 1 40.00 10 Pressure transmitter HBY-2000 sets 1 3000.00 11 Frequency Converter VF-55KW Taiwan 1 18000-35000.00 12 Box Table 1 1000.00 13 Main Line Approval 1 200.00 14 Accessories Fee Approval 1 200.00 15 Remark 16 Total Cost 26310.00 ~ 43310.00 Serial No. Material Name Model Specification Unit Quantity Unit Price Amount 1 circuit breaker CM1-225M / 33002 160A only 3 650.00 1950.00 2 AC contactor CJ20-160A 380V only 4 380.00 1520.00 3 Current Transformer BH-0.66 150/5 only 2 50.00 100.00 4 ammeter 6L2-A 150/5 only 2 40.00 80.00 5 voltmeter 6L2-V 0-450V only 1 40.00 6 lights AD11-25 / 40 only 5 10.00 50.00 7 control button LAY3 only 6 15.00 90.00 8 General relays HH54P only 4 10.00 40.00 9 Level controller YJ-712 only 1 40.00 10 Pressure transmitter HBY-2000 sets 1 3000.00 11 Frequency Control VF-55KW Taiwan 1 18000-35000.00 12 Box table 1 1000.00 13 The main line approved 1 200.00 14 Fees approved 1 200.00 15 Remarks 16 Total cost 26310.00 ~ 43310.00 No. Name of the material Model Unit Quantity Price Amount 1 Circuit breaker CM1-225M / 33002 160A only 3 650.00 1950.00 2 AC contactor CJ20 -160A 380V only 4 380.00 1520.00 3 Current Transformer BH-0.66 150/5 only 2 50.00 100.00 4 ammeter 6L2-A 150/5 only 2 40.00 80.00 5 Voltmeter 6L2-V 0-450V only 1 40.00 6 Signal Light AD11-25 / 40 only 5 10.00 50.00 7 Control button LAY3 only 6 15.00 90.00 8 General relays HH54P only 4 10.00 40.00 9 Level controller YJ-712 only 1 40.00 10 Pressure transmitter HBY-2000 sets 1 3000.00 11 Frequency Governor VF-55KW Taiwan 1 18000-35000.00 12 Box table 1 1000.00 13 The main line approved 1 200.00 14 Accessories fee approved 1 200.00 15 Note 16 Total cost 26310.00 ~ 43310.00 yuan