A manufacturer that produced a blend of powders for consumers contacted EXAIR for electrical panel cooling. They had two large mixers that would mix different powders. One mixer could fit a total weight between 2,200 lbs. to 4,400 lbs. (1000 kg to 2000 kg) of powder. The second one was between 220 lbs. to 2,200 lbs. (100 kg to 1000 Kg). By mixing powders, this was a very dusty environment. One potential problem was the over-temp fault with their VFDs, (Variable Frequency Drives). VFDs control the speed of the motors that run the paddles. In this industry, production is very extensive, and they wanted to prevent the fault with over-heating from occurring.
In our discussions, they were interested in our EXAIR Cabinet Coolers. I asked the general questions to correctly size the Cabinet Cooler. For this electrical panel, they used panel fans to cool the internals. Some problems with panel fans are that they will draw the warm ambient air to try and cool what’s inside. It can make it difficult during high summer temps. Also, fans require filters to remove the dust from the environment from entering the cabinet. The plant had a dirty environment and the powder was able to clog the filters. This condition reduced the effectiveness of fan cooling and still allowed dust to get into the electrical panel. The result was that the VFDs were unable to operate properly under such conditions.
EXAIR Cabinet Coolers have an option called the Non-Hazardous Purge (NHP) System. This product is designed to continuously bleed about 1 SCFM (28 SLPM) of compressed air into the cabinet when not operating. This will cause a slight positive pressure to keep any dust particles from migrating into the electrical cabinet. With the installation of the Cabinet Coolers, the vents and panel fans are removed and covered for proper cooling. This helps to reduce the amount of powder that can migrate into the panel and reduces the maintenance cost of changing or cleaning the panel filters.
From the heat load calculation, I recommended the NHP4340, which produces 2,800 BTU/hr of cooling. With this complete system, which included the thermostat control and the NHP solenoid valve, the company was able to save compressed air during the cooler months, keep the dust out of the electrical panel, and had a reliable way to keep the VFD from tripping on high heat. If you would like more information about our Cabinet Coolers, you can always contact an Application Engineer at EXAIR. We will be happy to help you.
John Ball
Application Engineer
Email: [email protected]
Twitter: @EXAIR_jb
