June 19, 2023
As a maintenance electrician, in addition to reasonable installation, good debugging, and daily maintenance and inspection of equipment and lines, he can quickly find out cause of failure and correct failure correctly when equipment fails. Ensure normal operation of equipment.
Every minute is wasted when equipment fails and production stops. How to quickly fix a hardware problem?
1. Resistance method
Usually refers to method of using a multimeter's electrical barrier to measure whether a circuit, contact, etc. is on or off. Sometimes a multimeter or bridge is used to measure whether resistance value of a coil is within its nominal value, and a megger is also used to measure resistance insulation between phase and phase, phase and earth, etc.
When measuring, pay attention to range selection (in general measurement channels, select a lower gear); compare meter readings; pay attention to presence of other chains so as not to make a mistake in assessment; most importantly, it is strictly forbidden to measure electricity.
2. Stress Method
This refers to method of measuring voltage value of a circuit using appropriate voltage range of a multimeter.
First measure voltage at input terminal to determine if line is normal, and then measure voltage at load terminal, which can be checked and measured step by step. Pay attention to position of meter gear when measuring, select appropriate range, and pay attention to positive and negative polarity when measuring DC current.
3. Current method
Determine cause of problem by measuring whether line current is normal. Low current circuits are often measured by connecting an ammeter or multimeter in series with a current block in circuit, and high current circuits are often detected with current clamps.
4. Replace method
When a component is suspected to be faulty but cannot be identified and a replacement is available, test can be replaced to see if fault is fixed.
5. Short connection method
Suitable for low voltage, low current loops, a method of shorting moderate points with thick test wires.
However, it must be confirmed that a short circuit will not cause a short circuit, and operation after a short circuit will not cause harm. Live shorting is prohibited and generally beginners should not use it.
6. Direct test method
By understanding cause of failure, or from experience, failure rate is often high and then some special failures occur, you can directly check suspected failure point.
7. Instrument test method
Measure various parameters with a variety of instruments and meters, such as observing waveform changes with an oscilloscope to analyze cause of a failure. It is mainly used in low current lines.
8. Exclusion method
In event of a short circuit, some lines can be phased out to determine range and fault point.
9. Setting parameter method
The components in some lines are intact and line wiring is good, but system cannot work properly due to incorrect setting of some physical values (such as time, offset, current, resistance value, temperature feedback signal strength, etc. e.) At this time, it should be adjusted according to original wiring diagram and specific conditions of equipment.
10. Comparative analysis and evaluation method
According to operating principle of system, control link action program and logical relationship between them, combined with fault phenomenon, compare, analyze and evaluate, reduce measurement, inspection and other links, and quickly evaluate fault range.
Assessment based on analysis and comparison can reduce number of links to review, reduce errors, and speed up troubleshooting. It is suitable for directly identifying fault area or fault point of some lines, and also needs to go through whole troubleshooting process.
Electrical equipment inevitably breaks down during operation. How to find out cause of breakdown and eliminate it in a short time is a test of abilities of a repair electrician, which is also basis for survival of maintenance personnel. electrician.
In practical application, we still need to analyze specific problems and use them flexibly.
