Electricians must have professional knowledge and sufficient theoretical principles as the basis, so that faults can be immediately and accurately judged and analyzed. Here are several commonly used methods for troubleshooting power system faults.

1. Resistance test method

The resistance test method is a commonly used measurement method. Usually refers to a method of using the resistance file of a multimeter to measure whether the motor, circuit, contact, etc. conform to the nominal value and whether it is on or off, or use a megohmmeter to measure the insulation resistance between phases and phases and between phases and ground. Wait. When measuring, pay attention to selecting the used range and the accuracy of the calibration table. Generally, when using the resistance method to measure, the general method is to select a low-end first. At the same time, pay attention to whether the line under test has a loop, and live measurement is strictly prohibited.

2. Voltage test method

The voltage test method refers to a method of measuring the voltage value in the circuit by using the corresponding voltage file of the multimeter. In general measurement, sometimes the voltage of the power supply and load is measured, and sometimes the open-circuit voltage is also measured to determine whether the line is normal.

When measuring, you should pay attention to the gear position of the meter and choose the appropriate range. Generally, when measuring unknown AC or open circuit voltage, the high voltage is usually selected to ensure that it is not operated under high voltage and low range to avoid damage to the meter; when measuring DC at the same time , Pay attention to the positive and negative polarity.

3. Current test method

The current test method is a method that usually measures whether the current in the line meets the normal value to determine the cause of the fault. For weak current circuits, the current gear of an ammeter or multimeter is often connected in series in the circuit for measurement; for strong current circuits, a clamp-on ammeter is often used for testing.

4. Instrument test method

Use various instruments to measure various parameters, such as observing the waveform and parameter changes with an oscilloscope, in order to analyze the cause of the fault, and it is mostly used in weak current lines.

5. Routine inspection method

Rely on human sense organs (such as: some electrical equipment has a burnt smell, ignition, discharge phenomenon, etc.) and with the help of some simple instruments (such as: multimeter) to find the cause of the failure. This method is commonly used in maintenance and is the first to be used.

6. Replace the original parts method

That is, when it is suspected that a certain device or circuit board is faulty, but cannot be determined, and there are substitutes, it can be replaced and tested to see if the fault disappears and returns to normal.

7. Direct inspection method

In understanding the cause of the failure or judging the location of the failure based on experience, you can directly check the suspected failure point.

8. Step-by-step elimination

If a short-circuit fault occurs, part of the line can be cut off step by step to determine the scope and point of the fault.

 9. Adjust parameter method

In some cases, when a fault occurs, the components in the line may not be bad, and the line contact is also good, but because some physical quantities are not adjusted properly or the running time is long, it may be possible that the system parameters may be changed due to external factors or the system cannot be automatically corrected. Value, which will cause the system to not work normally. At this time, it should be adjusted according to the specific conditions of the device.

10. Principle analysis method

According to the composition principle diagram of the control system, by tracing the signal associated with the fault, analyze and judge, find the fault point, and find out the cause of the fault. Using this method requires maintenance personnel to have a clear understanding of the working principles of the entire system and unit circuits.

11. Comparison, analysis, and judgment

It is based on the working principle of the system, the operating procedures of the control links and the logical relationship between them, combined with the failure phenomenon, to compare, analyze and judge, reduce the measurement and inspection links, and quickly determine the failure range.