------------------------------------- I have just replaced a pot that was replaced by one of my operators because I thought that he had connected it up badly but it seems we have greater issues. The pot controls the speed at which a cnc mahine runs. It originaly was 0% - left, 50 - %center and 100% full right. Now at about one twentieth of the way round it is already at 100%. Could it be that the cnc tech told me to get a pot with wrong amount of resistance? ##-----------------------------------------------# Article posted with Cabling-Design.com Newsgroup Archiv http://www.cabling-design.com/forum no-spam read and post WWW interface to your favorite newsgroup - sci.electronics.basics - 18431 messages and counting ##-----------------------------------------------##
Could be, but more likely, you replaced a linear pot with an audio (log taper) version. They have most of the resistance change concentrated at one end. http://sound.westhost.com/pots.htm#taper
Good morning, Kristen. You're right -- it might be possible the tech told you the wrong part number. As another post mentioned, it could also be that you've got a log taper. And pots have been known to be mislabelled - checking with an ohmmeter is a good idea. A couple of other things: * If there are three wires going to the pot, it's possible the wiper wire and one of the leg wires were accidentally exchanged. * A defect in manufacturing may result in intermittent contact between the wiper and the resistive element in the pot. It's a good idea just to take out the pot and check for this. You can also look at the log taper issue, as well as that it has the right value, and is not mislabelled. * Be sure to recheck the relevant connections and solder joints -- you're in an environment with some significant vibration, and something may have worked its way loose. Good luck Chris