Troubleshooting methods in electrical circuit control - Schneider

The troubleshooting method of the electrical control line is not the same as a thousand people, and various methods can be used cooperatively, but do not copy the rigid set. In general, investigative research can help us to find out the problem. The experimental method can not only find out the fault phenomenon, but also find the fault location or fault circuit; Logic profiling is a useful way to reduce the size of failures; Measurement is a fundamental, reliable and useful way to find out the point of failure. In the practice of maintenance operations, it should be done after each troubleshooting, summarize the experience in a timely manner, make maintenance records, as a file for future repairs, and after the analysis and maintenance of each fault, take active and useful measures to avoid similar problems again.

Troubleshooting methods in electrical circuit control - Schneider

Troubleshooting methods in electrical circuit control - Schneider

Generally speaking, according to the phenomenon of equipment problems, the scale of the problem can be roughly determined as follows:

1) All button functions fail, and there is a high possibility of power supply failure or fuse problem.

2) Some buttons are invalid, and some buttons are functioning normally. At this moment, the problem is mostly in the common part of this part of the circuit or the power supply part of this part of the circuit.

3) A single button or a single function fails, and the button itself and the lead wire are more likely to have problems.

4) Most of the problems, if it is equipment that has not been used for a long time, it may be the problem of poor contact or leakage, or other problems caused by poor contact and leakage.

5) Soft fault, if there is a certain law with time or external environment, it may be that the circuit is connected with the external environment and part of the performance is deteriorated, and it will be affected. If there is a certain relationship with the operation time, the Schneider inverter is greatly affected by the temperature, which may be the deterioration of the performance of the component, such as leakage, unstable performance or dirt. For example, the reversible control of a motor presents the problem that it cannot rotate forward, but can only rotate. According to this feature, it can be roughly determined that the scale of the fault is in the forward control circuit, but not in the motor itself and the rotary control circuit. Press the forward button and do not let go, and then press the rotary start button, the motor does not rotate to start, which clarifies that the button interlocking function is useful, and the circuit fault lies in the forward rotation control loop.

Then, following a step-by-step approach from back to front, look at the forward contactor first. Skip the button and other contacts of the coil lead, directly connect to the power supply, and after the power is turned on, the motor rotates forward, indicating that there is no fault with the contactor. Then connect the lead wire to the start button, turn on the power, press the start button, the motor rotates forward, and the forward rotation button is clarified. The dynamic breaking contact of one rotary button and the dynamic breaking contact of rotary contactor are only connected in series between the forward rotary button and the forward rotating contactor, and the circuit is faulty, and the fault point is on the dynamic breaking contact of the rotary button and the rotary contactor, and after viewing, it is found that the dynamic breaking contact of the rotary start button can not be closed well.

The common analysis methods for electrical control line faults include investigation and research method, experimental method, logical analysis method and measurement method.

1) Survey and research method. The investigation and research method is to "see", "listen", "smell", "touch" and "ask" to understand the obvious faulty phenomena; After visiting the operator, understand the cause of the problem; A common way to help find faults after asking others or consulting information. This method is highly efficient, empirical, and skilled, and needs to be continuously accumulated and summarized in long-term production practice.

2) Logical analysis. The logical analysis method is a method of fault analysis based on the operating principle of the electrical control circuit, the action procedure of the control link and the connection between them, combined with the fault phenomenon. It focuses on the fault phenomenon, analyzes the circuit specifically, improves the pertinence of maintenance, can shrink the target, and quickly identify the fault position, which is suitable for the fault viewing of complex lines.

3) Star measurement. The measurement method is a method of using a calibration lamp, a voltage tester, a multimeter, a buzzer, an oscilloscope, etc. to measure the live or power-off of the line. When using a multimeter ohmic block and buzzer to detect whether the electrical components and circuits are open or short-circuited, it is necessary to cut off the power supply. At the same time, special attention should be paid to whether there are parallel branches or other circuits that have an impact on the tested circuit when measuring, so as to prevent misjudgment.

4) Experimental method. The experimental method is a method to find faults by electrifying experiments without damaging electrical and mechanical equipment. The power-on experiment is generally carried out in the form of "point and touch". If it is found that the operation of an electrical appliance does not meet the requirements, that is, the scale of the fault is in the circuit related to the appliance, and then further look in this part of the problem circuit, you can find out the fault point. Sometimes it is also possible to temporarily cut off part of the circuit (such as the main circuit) to check whether the action of each control link is normal, but it is necessary to be careful not to use external force to make the contactor or relay act at will, so as to prevent accidents.

Troubleshooting methods in electrical circuit control - Schneider

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