It’s Summer, it’s hot, and just about everywhere that sees the sun here in the US is currently pretty warm. This isn’t breaking news to anyone here in the Midwest, but it is also increasingly muggy and humid. I know this because the condensate drain on the A-Coil within my home HVAC system has been dripping more and more water down through the drain line and into the floor drain. I’ve also been watering my outdoor plants more and more frequently due to the lack of rain we have had the past month. At home, my HVAC system pulls moisture out of the air and lets it condense then pushes it down a drain. Out of sight and out of mind for most homeowners. In a manufacturing plant, that isn’t always the case because many have no climate control for their machine and production areas.
When I was in metal cutting, it was not uncommon for me to walk into a shop during the summer to repair a machine that had a thermal trip. Most of these machines that I worked on had simple air-to-air heat exchangers to cool the electrical cabinets which have a minimum of three variable frequency drives in them as well as a controller, many other relays, and circuits. Most machine shops I went into were also not climate controlled. The machining processes would build a mist and dust throughout the facility which would settle. The fan intakes would often not be maintained, and the cabinets would eventually overheat. Often, rather than cleaning the fans, the operators or maintenance would simply open the electrical panel doors and put a box fan blowing into the open panel, so they could finish cutting their parts.
While this would put the machine back into service it would also pull in all that warm humid air from the shop that was filled with the metal fines, oil mist, and other dirt. This would then blanket the inside of the panel and all the open circuit boards. Some of the drives would even have fans on them from the manufacturer to keep the inside cool which would just internally coat the surfaces with oil, dust and debris. Then, after that job was done, it would just roll into the next job because the “fix” was working just fine. Well, after a while of the machine running like this, the buildup settling onto the boards and internal fans coating the inside of the drives the machine would generally go down again and this time they couldn’t apply the same fix of opening the doors again. This is when I would get the call and have to deliver the bad news that I now have to clean and inspect all the boards and drives. Then, when we would get finished, the cycle would start over unless the customer took to heart that the fans have a much-needed preventative maintenance cycle, or they would have the fans removed and install a Cabinet Cooler System.
The advantage of the Cabinet Cooler System is that the panels stay sealed and maintain their NEMA rating all while receiving less than ideal maintenance intervals. In fact, the Cabinet Cooler itself has no moving parts and the only maintenance is to ensure the compressed air filter is clean and clear. This option would often result in fewer calls for overheated machines. I am fairly certain it may impact the sale of box fans to these machine shops. At the very least, the operators get to keep the fans for cooling themselves off rather than blowing into an electrical enclosure.
If you have seen an open electrical enclosure with fans blowing into it, then you know exactly what I am talking about. I hope you understand that an EXAIR Application Engineer can help you prevent that safety violation as well as a general, all around bad idea for the health of the components inside the cabinet.
Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF