Laboratory instruments are generally well maintained every three months, especially some precision instruments. If it is an instrument with a rechargeable battery, it should be charged every three months to avoid battery damage. Different instruments have different maintenance methods. According to different characteristics, measures such as dustproof, shock-proof and anti-corrosion are taken. See the maintenance instructions and frequency of use in each instrument's operating manual for details.
Electrical equipment maintenance principles
1. Move your mouth before you move
For faulty electrical equipment, do not start urgently, should first ask before and after the fault and fault phenomenon. For unfamiliar equipment, we must first be familiar with the circuit principle and structural characteristics, and comply with the corresponding rules. Before disassembly, fully familiar with the function, position, connection mode of each electrical component and the relationship with other surrounding devices. In the absence of assembly drawings, sketch and mark as you disassemble.
2. Outside-in
Should first check the equipment for obvious cracks, defects, understand its maintenance history, service life, etc., and then check the inside of the machine. Before removal, the peripheral fault factors should be queued up, and the equipment can be removed after determining that it is an internal fault. Otherwise, blind removal may make the equipment worse and worse.
3. Mechanical before electrical
Electrical inspection should only be carried out after the mechanical part has been confirmed to be free of fault. When checking the circuit fault, the detection instrument should be used to find the fault location. After confirming that there is no bad contact fault, the operation relationship between the line and the machine is checked in a targeted manner to avoid misjudgment.
4. Static before dynamic
When the equipment is not powered on, judge the quality of the button, contactor, thermal relay and fuse of the electrical equipment, so as to judge the fault. Power test, listen to its sound, measure parameters, judge the fault, and then repair. For example, when the motor is out of phase, if it cannot judge the measured three-phase voltage value, it should listen to its sound and measure the voltage of each phase separately to determine which phase is defective.
5. Clean before repair
For electrical equipment with heavy pollution, first clean its buttons, wiring points, contacts, and check whether the external control key is invalid. Many failures are caused by dirt and conductive dust blocks, which are often eliminated as soon as they are cleaned.
6. Front power supply
The failure rate of the power supply part accounts for a high proportion in the whole fault equipment, so the power supply is often repaired first. You can get twice the result with half the effort.
7. General before special
Failures caused by low assembly quality or other equipment failures generally account for about 50% of common failures. The special faults of electrical equipment are mostly soft faults, which should be measured and repaired by experience and instruments.
8. First the outer week, then the inner week
Do not rush to replace the damaged electrical components, and then consider replacing the damaged electrical components after confirming the normal peripheral circuit.
9. Dc before AC
During maintenance, the static operating point of the DC circuit must be checked first, and then the dynamic operating point of the AC circuit must be checked.
