When the elevator control circuit fails, you must first ask, watch, listen, and smell. The so-called question is to ask the operator or the person who reported the fault when the fault occurs, to check whether any adjustments or replacement of the components have been done before the fault occurs; the so-called look is to observe whether each part is working properly, see the elevator control Whether the various signals indicate correctness, whether the appearance color of the electrical components changes or not. The so-called listening is to listen to the circuit when there is a strange sound; listening to the smell, is to smell the circuit components have an unusual smell. After completing the above work, the following methods can be used to find the fault of the electrical control circuit.
1, program inspection method
The elevator is operated according to a certain procedure. Each operation has to go through the cycle of selecting, orienting, closing, starting, running, changing speed, leveling and opening the door. Each step is called a work link, and each work link is realized. There is a corresponding control circuit. The program check method is to confirm which control link the fault occurs specifically, so that the direction of troubleshooting is clear, and it is important to correct the fault. This method is not only suitable for electrical control devices with contacts, but also for non-contact control systems, such as PC control systems or microcontroller control systems.
2, static resistance measurement method
The static resistance method is to measure the resistance of the circuit with a multimeter resistance file in the case of power failure, because any electronic component is made up of a PN structure, and its forward and reverse resistance values ​​are different, any one. Electrical components also have a certain resistance value, connected to the circuit or switch of the electrical components, the resistance value is not equal to zero or infinity, so measuring their resistance value to meet the specified requirements can be judged good or bad. This method can also be used to check for an electronic circuit with or without faults, and it is safer.
3. Potential measurement method
When the above method cannot determine the fault location, the potential of each electronic or electrical component device can be measured under the condition of power-on, because under normal working conditions, the potential of each point on the current closed-loop circuit is constant, and the so-called point potential refers to the circuit component. The potentials of the various points on the ground are different, and there is a certain size requirement. The current flows from the high potential to the low potential. The magnitude of the potential on the electrical and electronic components measured in the forward current direction should conform to this rule, and the control circuit is measured by using a multimeter. Whether the potential of the point meets the specified value can determine the point of the fault, and then determine what causes the current value to change, whether the power supply is incorrect, or the circuit has an open circuit, or the component is damaged.
4, short circuit method
The control link circuit is composed of a switch or a relay and a contactor contact. When it is suspected that some contacts are faulty, the contact can be shorted by a wire. If the fault disappears after power-on, the judgment is correct, indicating that the electrical component is broken. However, keep in mind that short wires should be removed immediately after the fault point test is completed, and short switches are not allowed to replace switches or contacts. The short-circuit method is mainly used to find the breakpoint of the electrical logic circuit. Of course, this method can also be used to measure electronic circuit faults. (http:// Copyright)
5, the breaking method
The control circuit may also have some special faults, such as the elevator stopping when there is no internal selection or outbound indication. This means that some contacts in the circuit are shorted. The best way to find such faults is to open the circuit. It is to disconnect the contact suspected of causing the fault. If the fault disappears, the judgment is correct. The open circuit method is mainly used. The point of failure of the "and" logical relationship.
6, the alternative method
According to the above method, it is found that the fault is from a certain point or a certain circuit board. At this time, the component or circuit board that is considered to be problematic can be removed, replaced by a new or confirmed faultless component or circuit board, and if the fault disappears, it is judged. correct. On the contrary, it is necessary to continue to search. Usually, the maintenance personnel have spare parts for the vulnerable components or important electronic boards. Once the fault is replaced, the problem is solved. The faulty parts are brought back and slowly searched and repaired. A quick troubleshooting method.
7. Empirical exclusion
In order to be able to quickly resolve, in addition to constantly summarizing their own practical experience, we must continue to learn from others' practical experience. The failure of the elevator is formed in a certain regularity. Some experiences are exchanged for sweat and lessons. We should pay more attention to it. These experiences can enable us to quickly eliminate faults and reduce accidents and losses. Of course, strictly speaking, elevator accidents should be eliminated, which is the responsibility of our maintenance personnel. Learning the experience of maintenance and troubleshooting at home and abroad can improve the technical level of elevator installation and maintenance personnel, and improve the service quality and credibility of the elevator industry.
8, the basic idea of ​​troubleshooting the electrical system
The electrical control system sometimes has complicated faults. At present, many elevators in China use microcomputer control, and the software and hardware are crossed together. When encountering faults, first of all, don’t be nervous, and when troubleshooting, insist on easy first, then first, then inside, comprehensive consideration, Some associations.
More faults in elevator operation are caused by poor contact of the switch contacts. Therefore, when determining the fault, the external line and power supply components should be inspected according to the fault and the indicator light displayed in the control cabinet. Safety loops, AC power supplies, etc., as long as you are familiar with the circuit, you can quickly solve it.
Some faults are not as simple and intuitive as relay circuits. Many protection links of PC elevators are implicit in its software and hardware systems. The faults and causes are exactly the same as the results and conditions. When looking for faults, they are orderly The relationship between the associations and predictions, the suspects are eliminated one by one until the fault is completely eliminated.
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