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Dynamic Braking with Prime mover failure

Posted by bobaroo7

on Thu, Dec 29 2005 12:13 AM

If one SD-40-2 is a four unit lashup suffers a prime mover failure while in dynamic braking mode, is the dynamic braking for that unit still functional?

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Posted by csxengineer98

on Thu, Dec 29 2005 6:15 AM

no, once a unit goes dead...the DB is dead... the only brakes that will work are the air brakes....
csx engineer

"I AM the higher source" Keep the wheels on steel

Posted by bobaroo7

on Thu, Dec 29 2005 8:54 AM

Thanks for the answer!

Happy New Year!

Posted by csxengineer98

on Fri, Dec 30 2005 4:07 AM

no problem
csx engineer

"I AM the higher source" Keep the wheels on steel

Posted by trainboyH16-44

on Fri, Dec 30 2005 1:26 PM

I thought that the dynamics were seperate from the prime mover. How is this not the case? IIRC, dynamics are the resistence of the traction motors, right? Correct me where I'm wrong..

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Posted by beaulieu

on Fri, Dec 30 2005 8:29 PM

QUOTE: Originally posted by trainboyH16-44

I thought that the dynamics were seperate from the prime mover. How is this not the case? IIRC, dynamics are the resistence of the traction motors, right? Correct me where I'm wrong..

You need the main generator to provide electricity to energize the fields in the traction motors.

Posted by rrandb

on Fri, Dec 30 2005 9:07 PM

QUOTE: Originally posted by beaulieu

QUOTE: Originally posted by trainboyH16-44

I thought that the dynamics were seperate from the prime mover. How is this not the case? IIRC, dynamics are the resistence of the traction motors, right? Correct me where I'm wrong..

You need the main generator to provide electricity to energize the fields in the traction motors.

I will try to keep this as simple as I can. I know you have heard that in dynamic brake mode (DM) the traction motors (TM) act as generators and now feed electricity to the dynamic brake grid where it is dissapated as heat. This generation provides resistance to slow the train. The TM's are not built as generators but as motors and need the electricity of the engine to provide this function. This a simplistic answer to a very technical question. What beaulieu said.. [2c] ENJOY

Posted by rrandb

on Fri, Dec 30 2005 9:09 PM

QUOTE: Originally posted by trainboyH16-44

I thought that the dynamics were seperate from the prime mover. How is this not the case? IIRC, dynamics are the resistence of the traction motors, right? Correct me where I'm wrong..

[#ditto] Same answer. The important thing to remember is they are traction MOTORS not traction GENERATORs. nuff said ENJOY

Posted by csxengineer98

on Sat, Dec 31 2005 8:39 PM

check this sight out...gives you alot of information on alot of locomotive systems...
http://travel.howstuffworks.com/diesel-locomotive9.htm
csx engineer

"I AM the higher source" Keep the wheels on steel