A garbage facility opted to start a preventative maintenance program. They looked at different areas that would create potential problems and stoppages within their processes. One issue was the over-temp faults with their Variable Frequency Drives, VFDs, during the summer months. VFDs control the speed of motors and in a garbage facility, many motors are used for pumping, conveying, and sampling. When the internal temperature rises above the specification for the VFD, the system will trip and stop the motor from running. In this type of industry, delays are very costly. They wanted a way to prevent this from happening.
They contacted EXAIR because they were interested in our electrical cooling concept; the EXAIR Cabinet Cooler System. They generate cold air with no moving parts. They do not use any Freon or motors to operate; and they require very little to no maintenance. They only need clean dry compressed air to work. I sent the Cabinet Cooler Sizing Guide for the general questions to correctly size the Cabinet Cooler for each electrical panel. When they went to check the temperatures inside the cabinets, they noticed that the electrical components were dirty and dusty (reference photo below). This directed our conversation to another type of Cabinet Cooler System; the Non-Hazardous Purge System. Being that the environment was very dirty, the dust particles were able to get into every little crevice, crack, and slits where the wires were entering and exiting the electrical panels. With dirt and dust particles, this would create issues with the efficiency, effectiveness, and potential safety in the filthy electrical components.
An option that we discussed was the EXAIR Non-Hazardous Purge (NHP) Cabinet Coolers. This product is designed to continuously bleed about 1 SCFM (28 SLPM) of compressed air into the cabinet. A slight positive pressure is created to keep any ingress of dust particles from getting into the electrical cabinet. EXAIR offers the NHP models from 275 BTU/hr (69 Kcal/hr) to 5,600 BTU/hr (1,411 Kcal/hr) cooling capacities. From the heat load calculations for the panel above, they needed a model NHP4340 which has 2,800 BTU/hr (706 Kcal/hr) cooling capacity. This size would keep the internal temperature less than 95oF (35oC) even during the hottest day of the hottest month.
The Non-Hazardous Purge Systems accomplish two things: keep the electrical components cool during heavy operations and warm temperatures; and keep the electrical components dust free. With this type of complete system, it will also include the thermostat control to save on compressed air during non-peak times and cooler months. Now that I shared the maintenance program from this garbage company, you can review your electrical panels to determine any short-comings with summer approaching. If you have any questions, you can contact an Application Engineer at EXAIR. We can help you to keep your facility from getting into a hot “stinking” mess with shutdowns.
John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb