Application of the most popular Emerson frequency

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Application of Emerson frequency converter in the transformation of gantry planer to milling machine

gantry planer is a large machine tool for preliminary machining. Due to technical limitations, the gantry planer workbench in the 1950s was driven by motor expander DC generator DC motor, resulting in high failure rate, large volume, high power consumption and backward technology. And its working instruments and devices: tensile strength tester and sample cutter. The way is to cut when the workbench moves forward and not cut when it moves backward. The workbench moves backward to prepare for the next cutting. The workbench moves backward, which is equivalent to not doing useful work and wasting time. Therefore, the user proposed to transform it into a Longmen milling machine. The following is an introduction to the transformation

the transformation scheme is: 1. The original mechanical reducer is retained for the workbench drive, plus a level 1:75 worm gear reducer. The 55kW DC main motor that originally drives the workbench for reciprocating motion is removed and replaced by a 5.5kW 4-level AC asynchronous motor driven by Emerson evt0075g 7.5kW g frequency converter. Because the forward speed of the workbench is very slow, it only needs to advance 2cm per minute, so the power of the main motor of the workbench is not necessary to be very large. The purpose of increasing the mechanical reduction ratio is to make the frequency converter work above 10Hz and avoid the low-speed crawling phenomenon of the workbench. The power selection of the frequency converter is one level higher than that of the motor to prevent the overcurrent of the frequency converter at low speed. The key point of the transformation is that the workbench cannot produce low-speed crawling. Table motor control requirements: use the

button to achieve 2. The purchasing skills of spring tension and compression testing machine are forward, reverse and shutdown. There are two ways of frequency setting: 1 Adjustable speed range (0~50hz). 2. Fixed high gear: 80Hz. The adjustable speed gear allows the speed of the workbench to be adjustable during milling, and the fixed high speed gear allows the workbench to move quickly manually when it is not milling. The adjustable speed gear is realized by the remote control box, and the fixed high-speed gear is realized by the switch. The method is to use the switch to close the frequency converter X3, short circuit X1 and X2 terminals, and the switching frequency given channel is VCI analog given, and when the switch is disconnected, it is digital given 3 (given by the serial port)

2. Remove the original planer and accessory devices on the cross beam tool holder of the gantry planer, install the upper milling cutter and vertical milling power head (equivalent to a gear reducer), the output shaft of the power head drives the milling cutter to rotate, and the input shaft of the power head is driven by 7.5kW 4-stage AC asynchronous motor, equipped with ev2000-4t0075g frequency converter. Control requirements: use buttons to realize forward and reverse rotation and shutdown, and the frequency is adjusted in the remote control box

3. The cross beam cutter (that is, the milling cutter moves horizontally left and right) motor was originally a 3.7KW 4-stage AC asynchronous machine, which is only equipped with an ev2000-4t0037g frequency converter. The control mode is the same as that of the workbench, and there are two modes of speed setting: 1 Given by serial port of remote control box (0~50hz), 2 When the switch is turned on, the 80Hz setting is fixed. The method is to use the switch to close the inverter X3 and short circuit X1 and X2 terminals. The switching frequency setting channel is VCI analog setting, and when the switch is turned off, it is digital setting 3 (serial port setting). Specific parameters: f7.00=22, f7.01=23, f7.03=24. Here, the VCI analog setting is to short circuit RF and VCI when the set value of inverter terminal V is less than 10% FS, which is equivalent to the maximum value of vci=10v. By setting f0.05=80hz, f0.12=80hz, f1.07=80hz, the switch is connected to the given 80Hz

4. The side milling power head motor is a 7.5kW 4-stage AC asynchronous motor, equipped with ev2000-4t0075g frequency converter. The terminal setting is used to realize forward and reverse rotation, and only the remote control panel is used to change the frequency, which is exactly the same as the control of the vertical milling power head. The R485 bus of the remote control panel is connected to the R485 terminals of all frequency converters. The frequency setting of all frequency converters can be adjusted by the remote control panel through serial communication, simplifying the control circuit

5. The last problem to be solved is the beam lifting and clamping control, which is also a key point of the transformation. The die beam of the gantry planer moves vertically up and down according to the height of the workpiece. It is driven by a 1.5KW 4-stage AC asynchronous motor to rotate the vertical screw rod. The beam lifting motor rotates forward to raise the beam, and the beam lifting motor reverses to lower the beam. Moreover, there is also a set of mechanical clamping device on the beam, which is driven by a 0.75KW AC asynchronous motor. After the beam beam beam moves up and down, the clamping motor rotates forward, so that the clamping pressure plate of the clamping device is tightly pressed on the track of the beam moving up and down, so that the beam will not move up and down when processing workpieces, so as to ensure the processing accuracy. When the beam moves up and down, the clamping motor should be reversed in advance. The beam can move up and down only after the clamping pressure plate is loosened. Use a double contact travel switch to detect the position of the clamping pressure plate. After the clamping pressure plate is pressed in place, the normally closed contact FSK of the travel switch is closed, and the normally open contact jxk is normally open. When it is released in place, the normally closed contact FSK is open, and the normally open contact jxk is closed. There is another detail: when the beam is lowered, while the clamping motor rotates forward, the beam lifting motor also rotates forward for 1~2 seconds, so that the beam rises a little, and then the beam is clamped. The purpose is to eliminate the clearance of the lifting screw rod of the cross beam. The function of SJ time relay is to make the beam rise back a few seconds, and its action is to close the contact after power on, and open the contact after power off. The whole beam action has only two buttons: Rise and fall. The beam clamping and placing is an ideal and excellent material in the high-temperature area of high-performance turbine engine. There is no need for buttons. It is automatically completed by the circuit. The beam lifting and clamping motor is not controlled by frequency converter. The figure below is a typical beam control circuit

summary: due to the use of Emerson EV2000 series frequency converter, the frequency setting channel is flexibly switched through the terminal, which realizes the serial communication frequency setting and the terminal VCI fixed frequency setting, which facilitates the operation, and improves the anti-interference ability by using the remote control panel The circuit is simplified. Because the frequency converter has the function of overload automatic frequency reduction, the workbench motor and power head motor never have overload shutdown, and the reliability is greatly enhanced

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