In the last few decades, the use of electrical enclosure cooling systems, or cooling cabinets, has grown exponentially. This is because the heat loads of cabinets has increased, and people are using more sophisticated equipment and drives.
Historically, enclosures for electrical equipment were simply ventilated and sometimes didn’t even have a fan. The views on this practice changed as equipment evolved and companies and maintenance staff starts to experience equipment failure, nuisance tripping, and variability of output. Eventually these issues were linked to the high temperatures in the enclosures, and fans were implemented. Even then, that wasn’t enough, so designers started to want enclosure air conditioning.
1. Control Enclosure Temperature Maximums
Unlike with more traditional electro-mechanical components, devices like variable speed drives have fairly low maximum operating temperatures. Not many devices can be used above 48C, and some are limited to 40.5C. Temperatures in Canada can get as high as 40C, which doesn’t leave much leeway when you figure in the heat produced by the equipment itself.
2. Keep Out Debris and Dirt
Enclosures have to be protected against dust, dirt, and fibres that can cause contamination and temperature rise. This means that an air conditioning system or air to air heat exchanger is best. Natural ventilation and fans simply do not work.
3. Prevent Water Entry and Malfunctions Caused by Overheating
In some industries, equipment has to be washed down and electrical components must be protected from high pressure water sprays.
Industrial controllers, drives, and PLCs are meant to work within tight temperature parameters. If they are allowed to work above the recommended temperatures, the variability of output that will affect device stability can lead to malfunction of the equipment.
4. Extend Component Life
The lifespan of electrical equipment is dramatically reduced with increases in temperature. PLCs, VFDs, and other equipment often have low max operating temperatures and running it close to or over its design temperature will reduce its life.
5. Remove Excess Heat
Because electronic drives generate a huge amount of heat, the enclosure needs to be able to remove that excess heat.
6. Prevent Entry of Corrosive Vapours
Like dust and dirt, corrosive gases and vapours need to be kept out of electrical cabinets. To avoid corrosion and damage to copper components, especially in coastal areas, it’s important that cabinets prevent the entry of corrosive vapours.
7. Maintenance Cabinet Cooling Systems
It’s not enough to just install a cabinet cooling system; it must be properly maintained. Dirt and debris must be removed from fins, fan blades, and filters, or to replace noisy fan motors. Before carrying out any maintenance, be sure the power is set to OFF. Maintenance tasks will vary depending on the type of unit.
8. Air Conditioning Units
Inspect the condenser fins and air filter for any build-up of dirt and debris. Clean and replace when necessary. Inspect the condensate management system and check for sale, sludge, and any other debris. Verify the fan is working and listen for unusual noises from the fan motors.
9. Filtered Fan Units
Any debris that is within 13 cm of exhaust and intake areas can restrict air flow and must be removed. Inspect filters for blockage and clean or replace as necessary.
10. Air-to-Air Heat Exchangers
The coil in heat exchanging systems requires occasional cleaning because the fins should be dirt-free in order to provide proper cooling. Also check to ensure the fan blades are clean and running smoothly.