9/18/2015 5:20 PM | |
Joined: 1/17/2006 Last visit: 8/18/2024 Posts: 553 Rating: (29) |
Hello. I'm facing a trouble with bearing wear of an induction motor connected to SINAMICS and I would like the help of experts or someone who has already faced this same problem. I have two induction motors and one of them has the problem of bearing wear (image_00). I've read several articles of EDM (electrical discharge machining) but I have doubts about the correct parameterization of drives with regard to the "P gain" and "Reset time" in current and speed controllers. I made a trace of the current Arms (r68[0] and r68[1]) of both motors and the graphs are attached as follows: Induction motor 01: 800KW / 660V / 847A / 1790rpm / 60 Hz Current controller: P gain= 0.211 and Reset time= 6,4ms Induction motor 02: 625KW / 660V / 680A / 1192rpm / 60 Hz Current controller: P gain= 0.309 and Reset time= 4,0ms
AttachmentImages.zip (208 Downloads) |
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9/19/2015 10:20 AM | |
Posts: 1529 Rating: (202) |
Unfortunately, your bearing picture is really small and hard to see. I don't see pitting, so It is not circulating current. Your waveforms looks fine and only in extreme unstable operation would tuning effect bearings. I would be looking at the more likely candidates, like motor/gear misalignment, lack of lubrication or other mechanical problems. Update: Looking at the picture some more (again, really hard to see), you may be experiencing a phenomenon call "fluting". This is caused by induced current going through the bearing and is always a potential in IGBT controlled inverters due to the high switching frequency. Normally, if the drive and motor are on the same ground, this is not an issue since the induced currents are small. There is no quick fix. Some things to try. 1. Make sure that the drive and motor are on the same ground Google "electric motor bearing fluting" and see if the pictures look like your bearings. There are lots of discussions about this for possible fixes, such as http://www.greenheck.com/library/articles/58. If it is a bearing current problem, there is nothing in the drive tuning that will do a damn thing about it. |
Last edited by: Jeff Casagrande at: 9/19/2015 11:05:52 AM |
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