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What to do when mechanical equipment floods in rainy weather?

August 17, 2023

Affected by the extreme rainfall of typhoon “Dusuri” this time, it has caused heavy rainfall in Fujian, Henan, Hebei, Tianjin and other places, and the production workshop was soaked in flood water, resulting in the stagnation of all production. What should you do if your equipment has been flooded or soaked in water to varying degrees? How to deal with it in the shortest time to reduce losses.

HLD gives you advice

  • Disconnect all power supplies to ensure that the whole machine is disconnected from the grid
  • When there is a hidden danger of water ingress in the workshop, please stop the machine immediately and turn off the main power supply to ensure the safety of equipment and personnel. If conditions permit, raise the entire line; if the conditions are not met, please protect the core components, such as the main motor, power cabinet, mobile operation panel, etc., which can be handled by partially raising them
  • If water has entered, please disassemble the computer, drive, motor and surrounding electrical components that are involved in the water, and rinse with clean water to remove surface dirt and impurities
  • Then process each part separately

How to deal with the hidden danger of water ingress in the electric cabinet?

  • Take measures to prevent the backflow of rainwater, take measures to drain the cable trench and block fire prevention. Also consider whether the electrical cabinet needs to be temporarily heightened and waterproofed.
  • Increase the threshold at the door of the power distribution room. A small amount of water seepage in the cable trench is not a big problem, because the cable surface material is waterproof. The cable trench should be covered with a cover plate to prevent the large-area water-filled cables from being soaked in water.
  • In order to prevent the phenomenon of short-circuit bombing, power outage measures should be taken immediately, and the main power supply should be cut off and sent to guard. Note: If there is water around the power distribution cabinet, do not use your hands when the power is cut off, use insulating rods or dry wood, wear insulating gloves, wear protective glasses, and stand on insulating mats to prevent electric shock accidents due to huge arcs.

What to do if the power distribution cabinet is flooded after rain?

  • The appearance of the electric control cabinet needs to be checked first. If there is obvious moisture or water immersion, the power cannot be sent immediately, and a professional electrician must do the following inspections:
    1、 Use a test pencil to check whether the electric control cabinet cabinet is live.
    2、Check whether low-voltage components such as control lines, control circuit breakers, intermediate relays, and terminal blocks inside the electric control cabinet are damp. If damp, dry them with drying tools in time. For components with obvious rust, Replacement is required.
  • Before the electric cabinet is powered on, it is necessary to test the insulation of each load cable, and the phase-to-ground must be qualified. If the rated voltage of the stator is below 500V, use a 500V shaker to measure the insulation value. The insulation value is not less than 0.5MΩ. Every element in the cabinet Devices are dried and air-dried.
  • Inverter water treatment method:

First of all, let me tell you clearly that it is not terrible for the inverter to be flooded. What is terrible is that it is almost hopeless if it is flooded and then powered on. It is a blessing in misfortune that it does not explode.

Secondly, when the frequency converter is not powered on, water ingress can be completely handled. If water enters during operation, although the damage to the frequency converter is a foregone conclusion, it must be powered off immediately to prevent its internal circuits from burning and causing a fire. At this time, attention should be paid to the fire prevention measures in place! Then let’s talk about how to deal with water ingress when the inverter is not powered on. The main steps are as follows:

1)Absolutely do not power on, first open the operation panel of the inverter, and then dry all parts of the inverter;
2) Dry the display, PC board, power components, fan, etc. of the inverter with a hair dryer and cold air. Hot air is not available at this time. If the temperature is too high, it is easy to burn out the internal components of the inverter;
3) Scrub the components in step 2 with alcohol containing 95% ethanol, and then continue to dry them with cold air with a hair dryer;
4) After drying in a cool and ventilated place for an hour, scrub them with alcohol again, and continue to dry them with cold air with a hair dryer;
5) Alcohol volatilization will take away most of the water. At this time, you can turn on the hot air (low temperature gear) and blow the above components again;
6) Then focus on drying the following inverter components: potentiometer, switching power supply transformer, display (button), relay, contactor, reactor, fan (especially 220V), electrolytic capacitor, power module, must be low temperature for many times For drying, switching power supply transformers, contactors, and power modules are more important;
7) After completing the above six steps, pay attention to check whether there is any water residue after the inverter module is dried, and then check again after 24 hours for any damp places, and dry the key components again;
8) After drying, you can try to power on the frequency converter, but you must ensure that it will be disconnected once it is connected, and then observe the reaction of the frequency converter. If there is no abnormality, you can power it on and use it!

If a customer says that I can’t disassemble it, what should I do? Then wait a few more days and let him dry naturally. After drying completely, use filtered compressed air to blow the inverter circuit board through the gap to prevent the dirt left in the rainwater. On the circuit board, it causes poor heat dissipation during operation, and the alarm stops.

To sum up, as long as the inverter is not energized when it enters the water, the inverter is generally not damaged. Other electrical components with circuit boards such as PLC, switching power supply, and air-conditioning system can refer to the above method.

  • Motor water inlet treatment method:

1) The motor should be removed and the power cord of the motor should be wrapped, the motor coupling, wind cover, fan blade and front and rear end covers should be removed, the rotor should be taken out, the bearing cover should be opened, and the bearing should be cleaned with gasoline or kerosene if the bearing is found When the wear is serious, it should be replaced), oil the bearing. In general, the amount of lubricating oil is one-half of the bearing for 2-pole motors, and two-thirds of the bearing for 4- and 6-pole motors.

2) Check the winding of the stator. Use a 500-volt megohmmeter to check the insulation resistance between the phases of the winding and the relative ground. If the insulation resistance is less than 0.5 megohm, the stator winding must be dried, and the winding is oily. It can be cleaned with gasoline. If the insulation of the winding has aged (the color turns brown), the stator winding should be preheated and then painted with insulating paint, and then dried.Drying method of the motor:  
Bulb drying method: use an infrared bulb to face the winding, and heat one or both ends at the same time;
2、Electric furnace or coal furnace heating method: put an electric furnace or coal furnace under the stator, and it is best to separate the furnace with a thin iron plate for indirect heating. Put an end cover on the stator and cover it with a sack. Turn the stator over and continue to dry, but pay attention to fire prevention, because the volatile gas in the paint and paint is flammable;

  • The motor has no water ingress but is damp. Treatment method:

Moisture is a fatal factor leading to motor failure. Splashing rainwater or moisture from condensation can invade the motor, especially when the motor is in intermittent operation. After it has been parked for several months, the coil insulation should be checked before use, otherwise It is easy to burn out the motor. If the motor is damp, the following methods can be used:

1) Circulating hot air drying method: Make a drying room with heat-insulating materials (such as refractory bricks), with an air outlet on the top and an air inlet on the side. The temperature of the hot air in the drying room is controlled at about 100°C.
2) Bulb drying method: Put one or several high-power incandescent bulbs (such as 100W) into the motor cavity for drying. Note: The light bulb should not be too close to the coil to prevent the coil from being burned. The motor casing can be covered with canvas or the like for heat preservation.
3) Desiccant:

(1) Quicklime desiccant. 

The main component is calcium oxide, and its water absorption capacity is realized through chemical reactions, so water absorption is irreversible. Regardless of the humidity of the external environment, it can maintain a moisture absorption capacity greater than 35% of its own weight. It is more suitable for low temperature storage, has excellent dry moisture absorption effect, and is relatively low in price.

(2) Silica gel desiccant.

This desiccant is different kinds of silica gel packaged in moisture-permeable small bags. The main raw material silica gel is a kind of hydrous silica with high microporous structure. It is non-toxic, tasteless, odorless, stable in chemical properties and has strong hygroscopicity. Relatively more expensive.

(3) Self-heating air-drying method:

 It is suitable for those who have no experience in handling tools and motors, but it takes a long time. This method must test the insulation performance of the motor before powering on.

In addition, we also need to remind everyone that in order to avoid the risk of electric shock due to water still remaining inside the machine, after confirming that the equipment is thoroughly dried, it should be placed in a ventilated and dry place for about a week before use, and the grounding wire of the whole machine should be checked to avoid The ground wire is short-circuited by water.

If you encounter a situation that you cannot handle by yourself, it is recommended to contact our company for inspection and maintenance to avoid more serious equipment failures.