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| Windings blew apart https://brainfiller.com/arcflashforum/viewtopic.php?f=2&t=2797 |
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| Author: | colp [ Tue Jun 18, 2013 10:13 am ] | ||
| Post subject: | Windings blew apart | ||
Hello Everyone, I have a ship that experienced a exciter failure. But there's the catch, the windings just blew apart, and mushroomed out, with little discoloragation of the windings. Was this just a electrical fault or did some other stressed come into affect. I have seen many burnt motors, but the windings always stayed intach. Thanks for any feed back, Steve
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| Author: | Larry Stutts [ Tue Jun 18, 2013 11:47 am ] |
| Post subject: | |
It looks to me like the exciter may have lost current. If there is enough residual magnetism and the shaft is lightly loaded, the speed can increase to dangerous levels. Did the RPM rise to some extreme level - like beyond maximum speed? I have seen DC motors fly apart because they lost field current without any significant load and the motor speed literally went through the roof. |
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| Author: | colp [ Wed Jun 19, 2013 4:52 am ] |
| Post subject: | |
Larry Stutts wrote: It looks to me like the exciter may have lost current. If there is enough residual magnetism and the shaft is lightly loaded, the speed can increase to dangerous levels. Did the RPM rise to some extreme level - like beyond maximum speed? I have seen DC motors fly apart because they lost field current without any significant load and the motor speed literally went through the roof. Hello Larry , Thanks for your thoughts. I don't believe speed was a factor, as the exciter is install directly on the propulsion shaft. I have not seen the damage yet as vessel is headed to port. But it looks to me that maybe something came loose and tore the windings apart. Wouldn't the winding ends be burnt were it opened, also small pieces of wire blown everywhere, and it looks like the winding wire has sharp edges leading me to think it was tore apart. Thanks, Steve |
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| Author: | Larry Stutts [ Wed Jun 19, 2013 5:11 am ] |
| Post subject: | |
colp wrote: Hello Larry , Thanks for your thoughts. I don't believe speed was a factor, as the exciter is install directly on the propulsion shaft. I have not seen the damage yet as vessel is headed to port. But it looks to me that maybe something came loose and tore the windings apart. Wouldn't the winding ends be burnt were it opened, also small pieces of wire blown everywhere, and it looks like the winding wire has sharp edges leading me to think it was tore apart. Thanks, Steve The fact that there were no visible arcing or burns is what got me thinking about current loss. But you're right it could be some other mechanical failure as well. |
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| Author: | Pete the "Dam" Engineer [ Mon Jun 24, 2013 8:10 am ] |
| Post subject: | |
Steve, The one item that I curious about what appears to be packing material to the right of the excitor, it could also be part of a surge ring but it is hard to tell from the photo. This definately looks like a mechanical failure and from the fact that there is not any visible burn marks, this failure occured with little or no power applied. |
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