Pete, youve already been way more help than the mfr reps. Seems like youre onto something. Wierd thing is, I never got to remove...disconnect this motor, others did and I was really scratching to understand how to hook it up. I do know there are 6 leads, always were and 3 terminals, (two each and not 1 each, with 3 bound together.) Since this is VFD the wye/delta start is not needed. Im willing to listen to your experience on this cuz ive tried all i know and it works well, just generates too much heat. Makes total sense downsizing wire if he couldnt get wire in slot.
Ross, your right also, i'm guessing where this came from, chicago pneumatic, 400v might have been the likely voltage fed to vfd so wouldnt have been any more available. I did talk with rep of mfr. Of drive, danfoss, and he said it was capable of outputting 480 no problem but then encountered the locked software. Soon i should know if they will send a guy out to change it. If not, im tempted to reload danfoss software, my hesitancy on that involves liabilities of a blown compressor. Even though i know zero chance of a voltage change causing that its just the idea of a modification. Changing a volt setting in my opinion is not changing functional design. Reloading software deleting I/O and rewiring/configuring the pressure control loop is changing design. At the time of failure a new motor did not exist even though this unit is little more than 10 yrs old. Now i really wish id have insisted on a "new motor". Yet this issue existed when it was delivered new. What Pete describes with need for insulated bearings etc fits this description exactly. Any thoughts if bearing arcing is a function of heat or not related? Ive heard of this before, even seen it but ive never understood it. Is it always a VFD that causes it? Or is it motor design? Maybe we could remove the vfd, put wye/delta contactors for startup and run it direct. Ha, here i go again wanting to change design. I better stop thinking about this
Thanks a million guys! Your input is appreciated!