It is currently Tue Sep 26, 2017 1:02 pm



Post new topic Reply to topic
Author Message
ekstra   ara
 Post subject: Windings blew apart
PostPosted: Tue Jun 18, 2013 10:13 am 
Offline

Joined: Fri Jan 06, 2012 7:44 am
Posts: 18
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


You do not have the required permissions to view the files attached to this post.


Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Tue Jun 18, 2013 11:47 am 
Offline
Sparks Level
User avatar

Joined: Tue Apr 17, 2012 8:19 am
Posts: 240
Location: Charlotte, NC
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.


Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Jun 19, 2013 4:52 am 
Offline

Joined: Fri Jan 06, 2012 7:44 am
Posts: 18
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


Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Wed Jun 19, 2013 5:11 am 
Offline
Sparks Level
User avatar

Joined: Tue Apr 17, 2012 8:19 am
Posts: 240
Location: Charlotte, NC
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.


Top
 Profile Send private message  
Reply with quote  
 Post subject:
PostPosted: Mon Jun 24, 2013 8:10 am 
Offline

Joined: Mon Jun 24, 2013 7:55 am
Posts: 1
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.


Top
 Profile Send private message  
Reply with quote  
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 7 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
© 2017 Arcflash Forum / Brainfiller, Inc. | P.O. Box 12024 | Scottsdale, AZ 85267 USA | 800-874-8883