1. Introduction
The transformation of spinning frame is mainly the transformation of frequency conversion and speed regulation of its main motor. The motor is an AC two speed motor with six poles at low speed and four poles at high speed, generally 17 or 19kw. Low speed mainly plays the role of mechanical equipment maintenance and spinning frame startup. When everything is normal, it will be switched to high speed. In this way, after the spinning frame is started normally, no matter in large, medium and small yarn segments, it will operate at power frequency 50Hz, so the yarn breakage rate is high. After the transformation of frequency conversion speed regulation, the operation speeds of different yarn segments can be adjusted artificially. In large, medium and small yarn segments with high breakage rate The frequency of the small yarn segment is appropriately reduced, and the frequency of the middle yarn segment with low breakage rate is appropriately increased. Because the length of the middle yarn segment accounts for the vast majority of the whole yarn length, this not only improves the production efficiency, but also reduces the breakage rate.
2. The electrical transmission mode of the main motor of the original spinning frame. The operation of the original spinning frame is mainly at the head, including some low-speed start buttons, high-speed buttons, stop buttons, steel collar plate reset, etc., while the electrical circuits and components are mainly distributed in the tail control box, mainly low-speed and high-speed main contacts and other intermediate relays. After high-speed start, low-speed does not work. It can only be started again after manual shutdown. The original spinning frame has a mechanical automatic doffing signal. After doffing, a relay outputs a pulse signal to stop the motor, that is, the so-called mechanical automatic doffing. The signal is controlled by the double cam mechanical structure of the spinning frame head and electromagnet. After doffing, a cam is pressed to a switch to output a relay contact signal, which energizes the electromagnet, Attract an armature to make the other cam act, reset the previous cam, reset the relay, and reset the steel collar plate, that is, the so-called three automatic; In case of manual shutdown, it is necessary to manually reset the steel collar plate and the manual cam mechanism. Some simple spinning frames have no mechanical automatic doffing function and are completely manually stopped, that is, they are manually stopped when the yarn is almost large. For this machine, the output signal of the frequency converter after the cycle is completed is very important. With this signal, this machine can be transformed into an automatic doffing function. After each doffing and yarn changing, just press the high-speed start button. a. In the control mode after frequency conversion transformation, under the condition of minimizing line changes and retaining the original operation mode, as long as the circuit is slightly modified, the frequency conversion control circuit is as follows:
The original low-speed function only plays the function of maintenance or commissioning on the frequency converter. After confirming that the machine is normal, because the frequency converter itself plays a smooth role, the high-speed is directly started, and the frequency converter operates at variable speed according to the set process curve. It should be noted that when the high speed is directly started after the low-speed start, because the motor has not been stopped, it is easy to report overcurrent for the direct start frequency converter of the running motor, and the speed detection start function can not play a fundamental role. Therefore, the low-speed function is generally not used for commissioning or maintenance. Since the frequency converter has a curve cycle to complete the output pulse signal, this signal is used to disconnect the high-speed main contactor and the operation signal of the frequency converter, so as to complete the electrical automatic doffing. It can be started directly at high speed at the next start. For the original spinning frame with mechanical automatic doffing function, it should be noted that the electrical doffing length should be set slightly greater than the original mechanical automatic doffing length, so that all links of the original mechanical doffing can be reset automatically before the completion of electrical doffing. In addition, when the sensor fails, the pulse loss processing is enabled through the parameter, and the frequency converter outputs the no length alarm signal and outputs it at the digitally set frequency. Therefore, the frequency should be set to zero, and it will be automatically started from the breakpoint after the fault is recovered. b. Spinning frame process curve and frequency converter parameter setting (1) process curve is as follows:
(2) Curve setting related parameters: pc.1-pc.15 set multi-stage speed frequency 1 - multi-stage speed frequency 15pc.16 set low-speed operation frequency pc.17-pc.30 set operation length 1 - operation length 14pc.32 set doffing length (doffing operation frequency is determined by parameter pc.15) C. description of process curve: (1) in the initial stage, the low-speed operation command of frequency converter is effective, and the frequency converter outputs low-speed operation command. (2) After canceling the low-speed operation command, the frequency converter runs the multi-stage speed process setting curve, and the frequency converter accelerates to multi-stage speed frequency 1. With the increase of the length of the first section, the frequency gradually increases. After running the length of the first section, the frequency converter runs at multi-stage speed frequency 2, and this process changes at a uniform speed. (3) The yarn length setting of each section increases in turn. Therefore, the parameter setting stage can start from the full yarn length and gradually reduce the length setting of each section. The length of each segment is limited by the parameters of the length of the next segment, which satisfies the following relationship: the first length < the second length < the third length........ < the 13th length < the 14th length. (4) . setting requirements: according to general experience: (4.1), the small yarn stage accounts for 15% of the total length, but the breakage rate accounts for 70%. Therefore, according to the situation of yarn, the output frequency of small yarn stage can be appropriately reduced to reduce the breakage rate. (4.2) the middle yarn stage accounts for 80% of the total length, and there are few broken ends, accounting for about 10%. In this stage, the motor speed can be appropriately increased to improve efficiency. (4.3). The large yarn stage occupies 5% of the total length and the broken end is 20%. In the large yarn stage, the output motor speed should be appropriately reduced to improve the product quality. The above parameters are set by the text display tp04g, and the text communicates with the frequency converter in real time to modify the parameters. Other parameter settings: P3.0 = 20, P3.1 = 21, p3.2 = 22, p3.3 = 23, p3.4 = 24, p3.8 = 16, P3.6 = 9, P3.7 = 10, p5.0 = 1011, P0.4 = 0001, p9.0 = 0114. D. heat dissipation mode of frequency converter. Since the special frame of spinning frame is designed to have no heat dissipation fan, it is necessary to use the heat dissipation air flow of spinning frame to dissipate heat to the frequency converter, At present, many factories use blowers to send the cold air from the outdoor to the main motor at the tail of each spinning frame through the trench to dissipate the heat of the motor, and the hot air is discharged from the workshop through the air duct. Therefore, an air duct can be used to lead the air from the motor inlet to the radiator of the frequency converter, and the hot air is discharged to the workshop. It is observed that the temperature of the frequency converter during long-term operation is between 55 and 60 degrees.