[AT] OT Cooling Electronics was Statistics In Tractor Manufacturing

James Peck jamesgpeck at hotmail.com
Sun Sep 22 07:08:54 PDT 2019


They may have given up on trying to keep electrical cabinets cool by natural means. A couple of years ago  I encountered a US built mechanical servo press that had a chiller mounted up on a top platform and water/air heat exchangers inside the electrical enclosures. The temperature switches would shut the press down if the temperatures inside the electrical cabinets rose into the upper nineties. The fan motors on the heat exchangers would get some dirt from air in their bearings and bind up. The cabinet would overheat and the temperature switch would shut the press down with a fault.



[[Stephen Offiler] It's a reasonable default position to assume competence, but by no means am I trying to say there aren't many exceptions.  If you think about it, it's less reasonable to take the opposite position and default to the assumption of incompetence.  You'd have a hard time ever trusting anything.



[ Jack] Around 40 years ago I was involved with technical support of a product that used an early PLC mated to DC Drives in cut to length on the fly machinery. At room temperature of around 98 oF, it would start to miscount. In fact, you could put your finger on the chip where the calculations were being performed and burn it. A muffin fan blew air in the direction of the overheated chip but wires obstructed the flow.



I went to R&D and asked what the test results were that resulted in the 40 oC rating. They said that was a standard rating. After some more questioning by me, it was revealed that there had been no testing done.
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