SEW servo drive maintenance

Servo drive
The series of servo drives are original products from Germany. The combination with the servo motor has the characteristics of high precision and stable performance, and is widely used in factories. The grinding process of the slope shell requires very high equipment precision. Generally, the grinding error of each product is within . The entire equipment is produced in the Netherlands, and its servo control part uses a servo controller and a servo motor.
1
Working principle

Basic principles of servo control system and foreign control part functions
Drive characteristics. The driver adopts its own positioning and sequence control system, has programming functions, and has the editing ability of assembly language and R language. You only need to copy the program to the driver controller according to the process requirements, and it can accurately position and execute according to the prefabricated program. It reduces the communication time and reduces the burden of processing other tasks, making it faster and more accurate. In addition, parameters can be read and written through the operating software, and information such as current, speed, temperature and/or signal in the graphic table can be displayed.
The composition and function of the servo control part. The servo control system of this equipment consists of servo driver origin switch B. direct-acting controller, braking resistor, servo motor with touch screen connected to the servo driver with incremental/absolute encoder, and programs written according to process requirements. .
The braking resistor is used to consume the extra power of the servo system when it is descending. B. The main function of the brake controller is to control the motor's brake when the servo drive is in the ascending state. The touch screen is human-machine display, and a window displays a graphic table. The current, speed, temperature and/or signal information in the drive can be modified, and various parameters in the drive can be modified, such as speed, position, slope, etc. Servo motors with incremental/absolute encoders are mainly used to drive mechanical movements, increasing The quantitative/absolute encoder feeds back the position and speed information of the motor to the driver. The origin switch gives the driver a zero pulse signal to determine the starting point of the stroke.

The working status and action sequence of the servo drive controller part
The R servo drive has three states of unloading and loading origin search in this grinding equipment.
Loading and unloading status. The detection of the photoelectric switch of the product transmits the signal and inputs the signal to the terminal of the driver. After receiving the signal, the driver drives the grabbing device to run downward according to the position and speed set by the touch screen (the speed and position parameters are set through the touch screen ), after the position is reached, the driver sends a signal from the 3-terminal terminal to confirm that it has lowered in place, and can proceed to the next action. If it is loading, then the photoelectric switch of the 3-terminal terminal has a signal input after rising, confirming that it has risen in place.
Origin search status. The origin search state is executed based on the signal from the photoelectric switch of terminal 3. The origin search is performed when the internal program of the driver cannot detect the switch signal just after the device is powered on or after the parameters are modified.
2. Common faults and solutions
. Provide operation signal to the driver
Since the driver directly drives the motor to run, the cause of the fault may be: insufficient three-phase voltage of the driver. The drive itself is faulty. The mechanical part driven by the motor is stuck. The operation signal does not reach the driver, and the internal program of the driver is lost or wrong. Generally, the internal programs of the drive are used and the error probability is not high, which can basically be ruled out. If the mechanical part is stuck, the drive will usually alarm and can be ruled out.
When dealing with faults, start with the simpler ones and then the more difficult ones. First use a multimeter to measure whether the voltages on terminals No. and 3 terminals meet the requirements. If normal, use a multimeter to measure whether there is a start-up signal voltage on terminal No. 3 terminals. If so, Normally, the operation signal has arrived. If there is no voltage, check the signal and wiring. The drive itself is a precision device, so the chance of damage is low. You can download the program first. If it is normal, the program will be lost, otherwise the drive itself will fail.
. The driver suddenly alarmed during operation (speed? error after)
The driver suddenly alarmed after running normally for a period of time, because it was speed? Finally, it shows that the running pulse sent by the driver is ahead of the actual running position. The fault may be: the three-phase voltage of the driver is insufficient or mutates. The load exceeds the rated power of the drive. Encoder wiring problem. Motor and lead issues. The speed setting exceeds the motor speed. B. The brake is damaged.
This system has been working for many years. Observe that the set speed is the same as before. The possibility of fault can be eliminated. The troubleshooting sequence is as follows. First, use a multimeter to measure whether the voltage on the terminals and 3 terminals meets the requirements. If it is normal, use a multimeter to measure it. Check whether the terminals are well connected and observe the motor leads. This problem is usually caused by B. brake damage, which can be eliminated by replacing it.
3
The driver will alarm as soon as the speed is high during operation (stop the chopper)
The driver of this machine can operate normally, but the speed cannot be set to 3r/. Other machines operate normally. Observe that the maximum speed of the servo motor and servo drive is both r/, which indicates that the parameter setting does not exceed the normal range. The fault may be: the driver parameter setting is incorrect. The load exceeds the rated movement rate of the drive. Caused by a fault in the drive itself.
When dealing with it, the first thing to think about is which parameter setting may be improper, which affects the speed difference. Copy the normally operating drive parameters to the drive to overwrite the original parameters. If the power-on failure still occurs, check the mechanical part and it is normal. Replacing the drive still does not work. , use a multimeter to measure the components around the driver, and find that the braking resistor has been disconnected, and the structure is infinite (normal?) After replacement, it starts up normally. The cause of the fault is that after the braking resistor burns out, it cannot consume the counter-electric force brought to the driver by the weight of the grabbing device itself

Calculation method of traction return flow in the rail under the direct supply plus co-current mode
According to the The distribution law of traction current, combined with the operation of the train (under normal circumstances), at a certain time, the current taken by each train at each time is,? . . . . . ? , so the current in the connected network at this time is:
For a given signal point, what is the current? What is the size of the mourning after it decreases to the end point? ? is the coefficient. Then the current flowing through the signal point is: According to the distribution law, when the train is exactly at this signal point, it is taken when there is suction on the line? ., take it when there is no suction on line? .When the train deviates from the direction of the substation at this signal point and is 3 years away from the signal point, what is the value? .3 When the train is between the signal point and the substation and is far away from the signal, what is the value?

Discussion on issues related to the calculation of traction backflow
It should be pointed out that the distribution of traction coflow in the rail cannot be expressed by a simple formula. It is related to rail impedance, earth conductivity, train position, etc. The locomotive flow is also a variable, related to line slope, curve, etc. Therefore, the above calculator is an approximate extrapolation.
In addition, non-insulated track circuits have certain special characteristics, that is, after a certain distance, the center lines of the upstream and downstream track circuits are connected, which are called equipotential lines. Their main function is to smooth the upstream and downstream traction currents. Obviously in most cases, the unbalanced pulling current is larger. Obviously in most cases, equipotential lines can play a role in reducing lines with large unbalanced traction currents.
Based on the above calculation. It can be seen that the traction current in the rail interferes with the track circuit under the direct supply mode. Combined with the sensitivity data in the previous section, it is believed that the Wujue track circuit can work reliably.
The sensitivity is .3, which is higher than the corresponding value for unbalanced traction current. Other sensitivity data are greater than the corresponding interference current values. Therefore, within the unbalanced current range, its harmonic interference will not cause malfunction of the equipment.
Conclusion
Uninsulated track circuits have good protection against interference. When the current is unbalanced, the interference voltage generated at both ends of the receiving end R is about.
The harmonic interference sensitivity data are all greater than the corresponding interference current values when the unbalanced current occurs. Therefore within the range, the harmonic interference data requires further testing.
3. Calculation of the interference of direct hooking method on uninsulated track circuits.
The return distribution of traction current in the rail is inconsistent under various power supply modes. In order to understand the degree of interference of the traction current in the rail to the uninsulated track circuit under the direct supply mode, the calculation method of the traction current at a given signal point is provided below, and through the calculation of two typical signal points on the Beijing-Zhengzhou Line Calculated as an example.
In the calculation, it is considered that there are mainly the following types of locomotives on the Beijing-Zhengheng line: therefore, the one with the highest power is used as the current flow value of the locomotive for calculation.

Distribution of traction current along the rail
The size of the traction current backflow at a certain point in the rail is inversely proportional to the distance between the train and the point. The closer the distance, the greater the current.
At a signal point with a suction line, when the train approaches the measuring point, the daily flow of traction current in the rail can reach 3. When the train is 3 meters away from the measuring point, the return current at the measuring point drops to 3.
The suction flow rate of the upper suction line is 3, which varies with the distance between the train and the upper suction line.
At the signal point where there is no suction line, when the train approaches the measuring point, the traction current in the rail returns approximately. When the train approaches test point 3, the return current at the measuring point drops to 3

Rail The relationship between the medium return current and the locomotive traction
Within the range, the rail medium return current and the locomotive traction current basically have a linear relationship.
3
Ignoring the two influences
The influence between the uplink and downlink catenary can be ignored. The reflow efficiency of double return lines is slightly greater than that of single return lines, but the impact is small.