7/17/2013 8:28 AM | |
Joined: 11/21/2007 Last visit: 8/12/2024 Posts: 2325 Rating: (308) |
Thanks PISCEAN 2010 I have mentioned in my post that no Alarms / Faults are displayed during optimisation. The Speed Feedback is using an Encoder and we have acceptabel speed stability in the base speed range. These are 400V, 375kW Motors ( kW Mentioned incorrect in my original question ). Right now line is in running condition. We will try to do the Magger test as soon as we can get a shutdown and post the results. However I remember we had done routine Megger Tests before commissioning and had not found any issues then. ( We had done Filed and Body as well as Armature & Body .. don't remember having done Field and Armature Test ) Cheers Navnag |
There is no such thing as the last bug in a program |
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7/17/2013 8:43 AM | |
Joined: 4/23/2010 Last visit: 12/31/2023 Posts: 8092 Rating: (877) |
Hello, Thanks for your reply. I strongly suspect that field & armatuer insulation is not strong sufficient. The flux distortion is the main reason of current flutcuation. I also suggest you to check the motor assembly properly. It may likely that armatuer interpole winding & field winding may be leaking. Can you measure earth or leakage current on line? Because drive will not sense the lekage current. It will trip only in case of over current or dead short. So please check this if it is possible. |
7/17/2013 8:57 AM | |
Joined: 11/21/2007 Last visit: 8/12/2024 Posts: 2325 Rating: (308) |
Thanks for the tips PISCEAN 2010. Will try to get it checked as soon as I possibly can. Will have to plan a shutdown with customer and send down someone with a Meggar How to measure earth or leackage current online ? Cheers Navnag |
Last edited by: Navnag at: 7/17/2013 8:58 AMThere is no such thing as the last bug in a program |
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7/17/2013 9:10 AM | |
Joined: 4/23/2010 Last visit: 12/31/2023 Posts: 8092 Rating: (877) |
Hello, Please find attached here with two separate links of measuring instruments. These are from India, you may get an equivalent from your country. Clamp on Earthmeter Leakage Current Tester. Put one of the meter on earth conductor or bus & measuer the current on line, i.e. when motor is running. Also observe the if the current increases when motor runs above the base speed, ( same as we measure the line or phase current with normal clamp on meter) Just note down & revert back the values. Hope this help you. |
Last edited by: PISCEAN 2010 at: 7/17/2013 9:15 AMProceduer of current measurment added. |
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