Application of the hottest delta BW series frequen

2022-07-23
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Application of delta BW series inverter in parallel continuous wire drawing machine Abstract: This paper mainly introduces the application of delta inverter in metal wire manufacturing industry. Debugging method of constant tension control through frequency converter

key words: Delta inverter metal wire constant tension control parallel continuous wire drawing machine

1 introduction

wire drawing machine is an important equipment in metal wire processing, which is used to process metal raw materials into wire of various specifications. The wire drawing machine is composed of paying off, wire drawing, water cooling, wire take-up and wire arrangement. The electrical transmission part is mainly realized by the paying off motor, wire take-up motor and wire arrangement motor. Its production quality and efficiency are very important for the enterprise. Wire drawing machines can be divided into three types: pulley type, looper type and linear type. From the point of view of using thermoplastic polyurethane (TPU) terminals, the wire drawing machine can be divided into large drawing machine, medium drawing machine, small drawing machine and micro drawing machine; In terms of the internal control mode and structure of the wire drawing machine, it can be divided into water tank type, pulley type, direct feed type, etc. For products with different requirements, different precision, different specifications and different metal types, different specifications of wire drawing machines can be selected. For wire and cable manufacturing enterprises with copper and aluminum substrates, the double frequency conversion control fine drawing machine is widely used, and its control performance is relatively low. For most steel wire manufacturing enterprises, in view of the steel characteristics, its precision requirements and drawing stability are high, so there are many direct wire drawing machines, and the working process of different wire drawing machines is basically the same:

paying off: l wire paying off speed, For the whole wire drawing machine, there is no high precision requirement for its control. For some double frequency controlled wire drawing machines, the wire tension of the wire drawing link can even be used to stretch through the disc. For most wire drawing machines, the control of setting out is realized by the frequency converter driving the setting out machine

wire drawing: l wire drawing is the most important part of the wire drawing machine. Different metal materials, different product accuracy and requirements, have different wire drawing links. The drawing part and paying off part of the dual frequency controlled wire drawing machine share a motor, and the metal wire is gradually stretched through the mold through the guidance of the internal tower wheel. The straight wire drawing machine has high drawing efficiency. For each drawing process, it needs a motor to drive, so its control is also the most complex

take-up: l the working speed of the take-up link determines the production efficiency of the whole wire drawing machine

2 structure of parallel continuous wire drawing machine

parallel continuous wire drawing machine is a direct continuous wire drawing machine used for drawing metal wires. All single wire drawing machines that form one or two continuous wire drawing machines are distributed side by side in 2 ~ 4 rows and placed on a rack with a vertical plane in a horizontal form at the same time. All die box devices are also set on the rack and make it form an included angle with the horizontal plane. The product has the advantages of small land occupation and It is conducive to improving labor productivity and realizing hygienic and civilized production

this paper takes the parallel wire drawing machine produced by a company in Xi'an as a design case. The parallel continuous wire drawing machine is a direct feed continuous wire drawing machine arranged in parallel. Its transmission, lubrication, cooling and control are the same as those of the vertical direct feed wire drawing machine. The appearance diagram of the whole machine is shown in Figure 1. The safety belt is an indispensable part of the automobile 1

Figure 1 parallel wire drawing machine

the machine has 10 tower wheels, 1 traction wheel, 1 winding wheel, 11 molds and 11 swing rods. The maximum incoming diameter is 2.4mm, the minimum outgoing diameter is 0.3mm and the maximum speed is 2.5m/s. The diameter of tower wheel is 250mm, the diameter of traction wheel is 360mm, and the minimum diameter of winding wheel is 280mm. The raw wire rod is drawn through 11 stages of 11 dies to become the finished wire rod with required wire diameter. Each tower wheel is controlled by a motor, and the traction wheel and winding wheel are also controlled by a motor respectively. Each tower wheel is equipped with a swing rod for constant tension control. Each motor is mechanically connected through a reducer, and the deceleration is as shown in Table 1 below (the reduction ratio G is the load side gear/motor side gear). The structure diagram of the whole machine is shown in Figure 2. Table 1 reduction ratio of reducer

Figure 2 Schematic diagram of complete machine structure

3 parallel wire drawing machine based on Delta BW series frequency converter

3.1 control principle

variable frequency constant tension drive of parallel wire drawing machine is to ensure constant tension of silk thread during operation. According to the different mechanical structures and materials, the constant tension control methods are generally divided into two types: 1. Directly control the motor output torque, 2. Ensure the constant tension by controlling the constant speed. Through the analysis of the mechanical structure, the project adopts the method of controlling the speed to indirectly control the constant tension

since the parallel wire drawing machine is composed of 11 groups of drafting mechanisms and 1 group of winding mechanisms, we analyze the control principle of a group of drafting mechanisms and a group of winding mechanisms separately. Figure 3 is the structural diagram of a group of drafting mechanisms

Figure 3 structure of drafting mechanism

ensure that the swing rod is in the set balance position without fluctuation during operation, so it can be determined that the tension on the silk thread is constant during drafting. So we can divide the control into two processes: stable process and self-regulation process

in the process of stable operation, we idealize the conditions (excluding the influence of other unstable factors), the swing rod will stop at the set position without fluctuation, and the tower wheel only needs to operate according to the calculated theoretical linear speed to ensure the constant tension of the silk thread. In this process, we only need to know the theoretical linear speed of the tower wheel in each drafting mechanism; Once the machinery is manufactured, the diameter of the tower wheel and the reduction ratio at the motor end have been determined. From the theoretical linear speed of the tower wheel, the actual running speed of the motor can be calculated, that is, the frequency of the frequency converter

there will be many unstable factors in the operation process, such as the slipping of silk thread, the change of mechanical friction, etc. the swing rod cannot be fixed. Therefore, the frequency converter needs to respond to the change of the swing rod and achieve the purpose of stabilizing the swing rod through the change of speed. This is the process of self-regulation. This purpose can be achieved through the PID operation of the swing bar signal by the frequency converter. Figure 4 is a detailed schematic diagram of the parameters of the traction drive mechanism. Let's see the relationship between the variables in the figure

Figure 4 traction drive parameters

in Figure 4, it is assumed that the diameter of tower wheel is r, the diameter of mold 1 is R1, the diameter of mold 2 is R2, the diameter of mold 3 is R3, the incoming diameter is R0, the reduction gear ratio of motor 1 is G1, the reduction gear ratio of motor 2 is G2, the command frequency of frequency converter 1 is F1, the command frequency of frequency converter 2 is F2, the linear speed of tower wheel 1 is V1, the online speed of tower wheel 2 is V2, n is the speed of motor 1, s is the slip ratio of motor 1, and P is the first-order logarithm of motor, T is the time. G1 is defined as (load side gear/motor side gear)

in the drafting mechanism, due to different mold sizes, according to the premise that the material volume passing through the mold in unit time is equal,

we know that: (r1/2) * π *v1 *t = (r2/2) * π * V2 *t

r1 * V1 = R2 * V2................................. ①

since R1 and R2 are known, V2 can be calculated according to V1

and V1 = π * r * n/G1, n = F1 * 60 * (1-s)/p

v1 = π * r * F1 * 60 * (1-s)/(G1 * P)

f1 = G1 * p * V1/(60 * π * r * (1-s)).......................... ②

the theoretical linear speed and theoretical frequency of each stage of drafting can be calculated through the above ① ② formula

Figure 5 shows the structure diagram of the winding mechanism Zhongwang, which can provide a series of services from automobile shape design, material structure design, aluminum body production line design, simulation analysis, sample vehicle output, etc

Figure 5 structural diagram of the winding mechanism

the control principle of the winding mechanism is different from that of the drafting mechanism in two aspects: 1. The linear speed of the winding mechanism and the traction mechanism is the same; 2 the winding diameter of the winding rod in the winding mechanism will change with the operation of the motor, and the winding diameter in the drafting mechanism is fixed. Therefore, for the frequency converter controlling the winding rod, it is also necessary to take the change of R into account and update the R value from time to time. The principle formula is the same as formula ②

3.2 application design of delta BW series inverter

the constant tension control system based on Delta BW series inverter is shown in Figure 6

Figure 6 constant tension control system of BW series inverter

the whole system is composed of 12 2.2kW motors, each of which is controlled by a 2.2kW BW series delta coiling process customized special inverter. Because delta BW series inverter has the special control function for coiling and unwinding, it can complete constant tension control without relying on PLC, and has the functions of automatic coil diameter calculation and PID automatic adjustment, Therefore, this system can independently control the unwinding action. The frequency converter amd1-amd10 needs to be configured with pg-03 card to complete speed detection and feedback closed loop. The tension control is completed by the frequency converter. The AVI terminal of delta BW series frequency converter receives the tension input signal of the tension bar. After the comparison and calculation of the preset tension balance parameters inside the frequency converter, the independent tension real-time control of the unwinding speed is made for the B. load element: 10t tension error. PLC is only responsible for giving the start signal and completing some auxiliary actions

⑴ wiring diagram of drafting mechanism is shown in Figure 7

Figure 7 constant tension traction control of BW frequency converter

amd11 traction frequency converter has avi as the main speed regulating signal, which is connected through an adjustable potentiometer; DFM is the frequency digital output, corresponding to the actual output frequency H (or the corresponding given frequency f can be selected), which is provided to the amd10 frequency converter as the actual linear speed signal. AVI in amd10 drafting frequency converter is the swing lever signal, which is used as the feedback of PID for fine adjustment; In pg03 -b accepts the linear speed signal sent by the superior as the calculation basis of the theoretical frequency; The DFM signal is transmitted to the next stage as the actual linear speed signal. The diameter of the tower wheel controlled by the drafting frequency converter is fixed through parameter setting. FWD is the operation signal, which is uniformly given by PLC; MI6 is a 1/2 acceleration and deceleration signal, which is used as an emergency stop

⑵ the wiring diagram of the winding mechanism is shown in Figure 8

figure 8 constant tension winding control of BW frequency converter

amd11 traction frequency converter AFM is an analog output signal, corresponding to the actual output frequency h, which is provided to amd12 frequency converter as an actual linear speed signal. AVI in amd12 winding frequency converter is the swing lever signal, which is used as the feedback of PID; MI1 is the winding diameter reset switch. When the winding rod is changed, the winding diameter reset operation is required. Since the diameter of the winding rod controlled by the winding frequency converter will change, it is necessary to turn on the automatic calculation function of the winding diameter. BW series frequency converter can automatically calculate the current winding diameter

3.3 parameter commissioning of delta BW tension control inverter

⑴ set motor nameplate parameters. Since there are requirements for the low-speed characteristics of the motor, it is necessary to use the vector control mode. The motor shall be self-tuning during commissioning

⑵ set the mechanical gear ratio. Fill in the gear ratio according to the actual mechanical conditions

⑶ calculate the theoretical linear velocity. Since the designed maximum linear speed (traction wheel) of the machine is 2.5m/s, according to the formula calculation, the traction frequency converter can meet the requirements when it works at 47Hz, so the working range of the traction frequency converter is set at Hz. With this basic linear speed, the theoretical linear speed on each tower wheel can be calculated according to the mold size provided by the customer; According to the theoretical linear speed, the maximum working frequency of each frequency converter can be calculated. It is assumed that the customer selects according to the die size data in the table below

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