Trains.com

Locomotive electrical output

17943 views
22 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    January 2003
  • From: Kenosha, WI
  • 6,567 posts
Posted by zardoz on Wednesday, July 23, 2003 1:15 PM
FYI-
The following info comes from a website known as "Howstuffworks", a really cool site that has lots to offer inquiring minds-like Mookie's.

19. What is shunting? As the speed of a locomotive increases, the traction motors generate large amounts of extra electricity that is simply not needed. This creates resistance in the motors (called counter-emf) and reduces the amount of amperage going into the motors, which limits speed. Shunting is a process in which the resistance is reduced by lowering the flow of electricity to the magnets that create the EM field in the motors without reducing the amperage. This lowers the resistance the traction motors face. (Think of shunting as like shifting gears in a car)

20. What is transition? A procedure that reduces the resistance the traction motors (see shunting) face by changing the proportion of amperage and voltage while not changing the output of the alternator. This reduces counter-emf. This allows the locomotive to develop more amperage and volts as needed. Transition may cause a brief interruption in tractive effort and can result in a broken coupler if slack develops and then the cars snap back as TE resumes. (Think of transition as like shifting gears in a car)

21. Do all locomotives have transition and shunting? No.

  • Member since
    January 2003
  • From: Kenosha, WI
  • 6,567 posts
Posted by zardoz on Wednesday, July 23, 2003 1:15 PM
FYI-
The following info comes from a website known as "Howstuffworks", a really cool site that has lots to offer inquiring minds-like Mookie's.

19. What is shunting? As the speed of a locomotive increases, the traction motors generate large amounts of extra electricity that is simply not needed. This creates resistance in the motors (called counter-emf) and reduces the amount of amperage going into the motors, which limits speed. Shunting is a process in which the resistance is reduced by lowering the flow of electricity to the magnets that create the EM field in the motors without reducing the amperage. This lowers the resistance the traction motors face. (Think of shunting as like shifting gears in a car)

20. What is transition? A procedure that reduces the resistance the traction motors (see shunting) face by changing the proportion of amperage and voltage while not changing the output of the alternator. This reduces counter-emf. This allows the locomotive to develop more amperage and volts as needed. Transition may cause a brief interruption in tractive effort and can result in a broken coupler if slack develops and then the cars snap back as TE resumes. (Think of transition as like shifting gears in a car)

21. Do all locomotives have transition and shunting? No.

  • Member since
    June 2001
  • From: US
  • 13,488 posts
Posted by Mookie on Wednesday, July 23, 2003 2:22 PM
Mookie's mind hasn't a clue what you are talking about.....

She who has no signature! cinscocom-tmw

  • Member since
    June 2001
  • From: US
  • 13,488 posts
Posted by Mookie on Wednesday, July 23, 2003 2:22 PM
Mookie's mind hasn't a clue what you are talking about.....

She who has no signature! cinscocom-tmw

  • Member since
    January 2003
  • From: Kenosha, WI
  • 6,567 posts
Posted by zardoz on Wednesday, July 23, 2003 2:32 PM
Mook-
You ask such interesting questions that to me you seemed like the type of person that was not only interesting, but interested in the world around them.
  • Member since
    January 2003
  • From: Kenosha, WI
  • 6,567 posts
Posted by zardoz on Wednesday, July 23, 2003 2:32 PM
Mook-
You ask such interesting questions that to me you seemed like the type of person that was not only interesting, but interested in the world around them.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Wednesday, July 23, 2003 4:05 PM
QUOTE: Originally posted by oltmannd

When starting a train, you want lots of pulling force. Pulling force is proportional to the current flowing thru the traction motors. If each motor can take 900 Amps and I put them all in parallel, I'd need a main gen that can do 5400 Amps! Meltdown city! If I put them all in series, I only need 900 Amps, but I'd need to do it a6 times the voltage of having them all in parallel

As a traction motor turns, it create "back EMF" or a voltage that opposes the voltage imposed on it. The faster it turns, the higher this back voltage gets. In order to keep the motors taking the same HP, I need to raise the voltage on them higher than the back EMF. Lets say, at 60 mph I need 900 VDC at full throttle. If I arrange my 6 traction motors in parallel, I'd need a generator that can do 6000 Volts. Flashover City! If I arrange them in parallel, I only need 900 volts (but 6 times the current).


Please clarify the bolded section, in parallel, they would need 6000volts, but in parallel, you'd need 900 volts but 6 times the current?
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Wednesday, July 23, 2003 4:05 PM
QUOTE: Originally posted by oltmannd

When starting a train, you want lots of pulling force. Pulling force is proportional to the current flowing thru the traction motors. If each motor can take 900 Amps and I put them all in parallel, I'd need a main gen that can do 5400 Amps! Meltdown city! If I put them all in series, I only need 900 Amps, but I'd need to do it a6 times the voltage of having them all in parallel

As a traction motor turns, it create "back EMF" or a voltage that opposes the voltage imposed on it. The faster it turns, the higher this back voltage gets. In order to keep the motors taking the same HP, I need to raise the voltage on them higher than the back EMF. Lets say, at 60 mph I need 900 VDC at full throttle. If I arrange my 6 traction motors in parallel, I'd need a generator that can do 6000 Volts. Flashover City! If I arrange them in parallel, I only need 900 volts (but 6 times the current).


Please clarify the bolded section, in parallel, they would need 6000volts, but in parallel, you'd need 900 volts but 6 times the current?
  • Member since
    December 2002
  • From: US
  • 286 posts
Posted by dekemd on Wednesday, July 23, 2003 7:07 PM
QUOTE: Originally posted by teddyA

QUOTE: Originally posted by oltmannd

When starting a train, you want lots of pulling force. Pulling force is proportional to the current flowing thru the traction motors. If each motor can take 900 Amps and I put them all in parallel, I'd need a main gen that can do 5400 Amps! Meltdown city! If I put them all in series, I only need 900 Amps, but I'd need to do it a6 times the voltage of having them all in parallel

As a traction motor turns, it create "back EMF" or a voltage that opposes the voltage imposed on it. The faster it turns, the higher this back voltage gets. In order to keep the motors taking the same HP, I need to raise the voltage on them higher than the back EMF. Lets say, at 60 mph I need 900 VDC at full throttle. If I arrange my 6 traction motors in parallel, I'd need a generator that can do 6000 Volts. Flashover City! If I arrange them in parallel, I only need 900 volts (but 6 times the current).


Please clarify the bolded section, in parallel, they would need 6000volts, but in parallel, you'd need 900 volts but 6 times the current?


It should read "If I arrange my 6 traction morors in SERIES, I'd need a generator that can do 6000 volts..... If I arrange them in parallel, I only need 900 volts (but 6 times the current).

Derrick
  • Member since
    December 2002
  • From: US
  • 286 posts
Posted by dekemd on Wednesday, July 23, 2003 7:07 PM
QUOTE: Originally posted by teddyA

QUOTE: Originally posted by oltmannd

When starting a train, you want lots of pulling force. Pulling force is proportional to the current flowing thru the traction motors. If each motor can take 900 Amps and I put them all in parallel, I'd need a main gen that can do 5400 Amps! Meltdown city! If I put them all in series, I only need 900 Amps, but I'd need to do it a6 times the voltage of having them all in parallel

As a traction motor turns, it create "back EMF" or a voltage that opposes the voltage imposed on it. The faster it turns, the higher this back voltage gets. In order to keep the motors taking the same HP, I need to raise the voltage on them higher than the back EMF. Lets say, at 60 mph I need 900 VDC at full throttle. If I arrange my 6 traction motors in parallel, I'd need a generator that can do 6000 Volts. Flashover City! If I arrange them in parallel, I only need 900 volts (but 6 times the current).


Please clarify the bolded section, in parallel, they would need 6000volts, but in parallel, you'd need 900 volts but 6 times the current?


It should read "If I arrange my 6 traction morors in SERIES, I'd need a generator that can do 6000 volts..... If I arrange them in parallel, I only need 900 volts (but 6 times the current).

Derrick
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Thursday, July 24, 2003 7:42 PM
Dekemd, Oltmannd,Zardoz and pfrench68 that gentlmen was a excellent job in explaining a complicated subject. I am very impressed with the talent on this WEB site.
TIM A
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Thursday, July 24, 2003 7:42 PM
Dekemd, Oltmannd,Zardoz and pfrench68 that gentlmen was a excellent job in explaining a complicated subject. I am very impressed with the talent on this WEB site.
TIM A
  • Member since
    December 2001
  • 17 posts
Posted by dfandrews on Thursday, July 24, 2003 8:41 PM
Info to stump your friends with:
According to a copper industry publication, there is about 88,000 lbs. of copper in a GE 9-44CW.
  • Member since
    December 2001
  • 17 posts
Posted by dfandrews on Thursday, July 24, 2003 8:41 PM
Info to stump your friends with:
According to a copper industry publication, there is about 88,000 lbs. of copper in a GE 9-44CW.
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Friday, July 25, 2003 4:42 PM
88,000 lbs at $0.50 a pound thats $44,000 dollars!!! We should go in the scrapper business. Buy up all the old engines at about $10,000 a piece, hire some homeless people to tear them apart. (Pay them in booze and provide them with a new refrigerater box) Thats good profit. Not to mention the scrap steel. Sounds better everytime I read it.
TIM A
  • Member since
    April 2003
  • 305,205 posts
Posted by Anonymous on Friday, July 25, 2003 4:42 PM
88,000 lbs at $0.50 a pound thats $44,000 dollars!!! We should go in the scrapper business. Buy up all the old engines at about $10,000 a piece, hire some homeless people to tear them apart. (Pay them in booze and provide them with a new refrigerater box) Thats good profit. Not to mention the scrap steel. Sounds better everytime I read it.
TIM A

Join our Community!

Our community is FREE to join. To participate you must either login or register for an account.

Search the Community

Newsletter Sign-Up

By signing up you may also receive occasional reader surveys and special offers from Trains magazine.Please view our privacy policy