Thursday, November 14, 2013

Forums on the Inter-web

Every notice when you search for something on the Internet, you will most always find a "forum" on the item or subject you have searched for?  Sometimes by accident you click on it and then realize that it is not what you were after?

So I end up on a HVAC forum and the subject is a service person at an office building in Utah (SLC area) has ABB drives on the air handling equipment.  He has been having failures on them and has slowly been changing them out to Toshiba units only to have the failures repeat on them as well. 

To figure out the problem, he gets on a "forum" and writes that the failures are occurring at about 6:00 am each and every time this happens.  His solution was to just jump to another brand when all he really needed was real guidance from someone with experience on drives and related problems.

Here's the deal, there were probably 10 plus responses to his question about what could be happening.  The answers where all over the place but way off target.  One even from a "ABB Technical Engineer", but no one addressed the real problem.

In most areas of the Wasatch Front, our utility uses capacitors to strengthen the lines during the day and takes them off-line at night when the demand for power goes down.  The "switching on" of these capacitors causes spikes in the line and if your system has no protection for these events, guess what happens?  The input of the drives on this building was and is still being pounded with these spikes every morning, and you know what time the utility normally switches these on,  yep.....6:00 am.

His problem could very well have been solved with the application of a simple line reactor on the input of each of these ABB drives.  But instead he received a bunch of advice from more people guessing what to do.  That resulted in spending money on the new drives (not to mention the labor to change them out, shipping, downtime and so on) but having the same problem. 

Have a problem and need help?  Your first source for help should be locating someone who is familiar with your application, equipment, area environment and has experience in what you need.  The Internet can be a great tool but like everything else, it needs to be used properly and wisely.


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