All equipment has aging phenomenon in the process of use, and there is a process of deterioration. This is more obvious in mechanical equipment, but it is difficult to observe in electrical equipment.
So for the electrical system, how to extend the life cycle of the stable operation of the equipment as much as possible? Today in this article we will discuss the impact of temperature and dust on the operation and maintenance of electrical equipment.
Motors, transformers, reactors and other equipment can be observed through temperature and electrical characteristics such as the resistance of the coil itself, insulation resistance to ground, and changes in current. However, it is difficult to monitor the degradation of electronic equipment. Therefore, electrical equipment needs to pay attention to daily maintenance to reduce or even eliminate the occurrence of unexpected accidents. Equipment maintenance is divided into online maintenance and offline maintenance. Some large equipment requires online maintenance. If possible, small and medium-sized equipment should be maintained offline after replacement.
In the process of using electrical equipment, temperature and dust are fatal hazards to electrical equipment.
High temperature damage to electrical equipment
High temperature will damage the insulation of electrical equipment, cause short circuit or grounding, and directly burn the equipment. The heating of electronic equipment is caused by power components, mainly diodes, thyristors, etc. Usually there are cooling fans, and some large equipment is also water-cooled.
1. Causes of high temperature
The high temperature is mainly caused by the heating of the equipment itself and the high ambient temperature on site.
The rated load of the equipment must be exceeded during use
The aging of mechanical equipment will also cause overload of electrical equipment
The equipment was impacted by high current, which caused the equipment to deteriorate over time
Loose bolts at the wiring part of the electrical equipment lead to inaccurate contact and heat generation.
The heat dissipation device fails, causing the temperature to rise.
2. General approach
Install thermal protection device and over-current protection device, so that it can stop in time when overload occurs
It is necessary to record the current and temperature observed daily in real time for easy analysis.
Find out the equipment with high current (relative to the rated value) and high temperature, and check it when shutting down.
For motors and reactors, the resistance and insulation resistance of key equipment are measured during shutdown.
Record the measured value and make a graph or curve to detect the deterioration.
Regularly replace the fan heating equipment according to the actual production situation, and perform maintenance after it is offline.
The heat dissipation part should be tested when the equipment is shut down.
During the inspection process, a temperature measuring gun needs to be used to measure the temperature. If the temperature rises, the machine must be shut down in time.
Dust damage to electrical equipment
Many factories are now implementing a spot inspection and regular repair system, and cleaning is particularly important for electrical equipment.
Dust will affect the heat dissipation effect of the device.
The dust contains metal particles, which will directly cause a short circuit when attached to the electronic components.
Although most of such equipment is installed in the power distribution room, dust will also enter it. Dust and clean electronic equipment regularly during routine maintenance.
1. Online dust removal and maintenance of electronic equipment
For example, for the inverter, first cut off the power supply in the stopped state, wait for 2-3 minutes, and operate after the discharge is completed. The rubber tube of the hair dryer can be extended into the device to blow out the dust. The dust on the power section and the cooling fan is the most. If necessary, you can open the casing of the device and blow the circuit board and silicon directly. It should be noted that do not touch the components inside. This step should be done by professionals.
2. On-line dust removal and maintenance of motors and transformers
The air quality is not good, and dust will be brought in when entering the motor
The powder after the motor carbon brush wears out will also enter the motor interior
Ordinary fans have low wind pressure and are difficult to clean. Compressed air must be used for blowing.
The carbon brushes should be replaced regularly during the maintenance of the motor. Pay attention to the direction of the carbon brushes and replace them in batches as much as possible.
The new carbon brush needs to be ground off in advance according to the arc of the commutator. Do not adjust the pressure of the top spring at will.
Summary and case
The maintenance of equipment must form a special record ledger, and the responsibility is assigned to people, not just a formality. Only by doing the work carefully can the maintenance of the equipment be done well.
"Insulation Resistance Remote Measurement Record"
"Equipment replacement ledger"
"Equipment cleaning and dust removal ledger"
"Inspection Record"
"Equipment Test Record"
The above is some experience in equipment maintenance. These need to form a normalized model in daily production, so that data is recorded, and there is an account for replacement and maintenance. If possible, the equipment after maintenance should be tested offline before going online to ensure that the spare parts can be used normally. Only with constant attention can we ensure the normal operation of online equipment and ensure the smooth progress of production.
Case:
The normal condition of the DC motor commutator is golden yellow with an oxide film formed on the surface. The powder after the carbon brush wears sticks to the commutator and the groove of the commutator, causing the commutator to turn black, which may cause the motor to be damaged. The fire even burned out the commutator.
In this case, compressed air cannot blow off the toner. You need to use a clean white cloth dipped in detergent or alcohol to wipe off the toner on the commutator, and then use a hook made of a hacksaw blade to change the direction. The toner in the groove of the filter hooks out. The oxide film on the surface of the commutator may be damaged after completion, and the load should be gradually increased after a period of operation under low load.