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  • Help with tractive effort/horsepower

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It is currently Tue May 28, 2024 6:28 pm

Help with tractive effort/horsepower

General discussion about locomotives, rolling stock, and equipment

Moderator: John_Perkowski

  by Nelson Bay
 
Mr. Locotester said:

[quote]
EMD’s earliest attempt at wheel slip control was pre dash 2 and called the “IDAC” system (Instantaneous Detection And Correction). Simply put, the motor currents of two motors were compared in opposition and the current of the slipping wheel would drop rapidly creating an imbalance in the circuit. If both motors of the set slipped simultaneously, and the currents remained equal, you could expect divots in the rail along with sparks and smoke.[quote]


Wheel slip control existed on EMD locomotives prior to IDAC. Simply put for sure. IDAC had 3 levels of correction severity. Simultaneous slips were controlled, abruptly, by the overvoltage protection circuitry of the control system.

  by ExEMDLOCOTester
 
ROTFLMAO !!!! Thats one way to describe it !!!!!!

  by Nelson Bay
 
ExEMDLOCOTester wrote:ROTFLMAO !!!! Thats one way to describe it !!!!!!

Thanks! That clears things up.

  by ExEMDLOCOTester
 
Nelson Bay wrote:
ExEMDLOCOTester wrote:ROTFLMAO !!!! Thats one way to describe it !!!!!!

Thanks! That clears things up.
Everytime I thought about the OV preventing a full wheel run away last night I chuckled, Thanks, you made my day....

  by Nelson Bay
 
ExEMDLOCOTester wrote:quote="ExEMDLOCOTester"]ROTFLMAO !!!! Thats one way to describe it !!!!!!
Everytime I thought about the OV preventing a full wheel run away last night I chuckled, Thanks, you made my day....
Read my post again Chuckles. Did I say OV prevented full wheel run away? I said controlled abruptly. Like by dropping out the generator field contactor. Control is to regulate or restrain, prevent is to keep from happening.

No comments on "EMD's earliest attempt at wheel slip control" or the "IDAC correction levels"???

And while you're at it, how about educating me on "ROTFLMAO"? Haven't seen that before.

  by ExEMDLOCOTester
 
Nelson Bay wrote:
ExEMDLOCOTester wrote:quote="ExEMDLOCOTester"]ROTFLMAO !!!! Thats one way to describe it !!!!!!
Everytime I thought about the OV preventing a full wheel run away last night I chuckled, Thanks, you made my day....
Read my post again Chuckles.

Did I say OV prevented full wheel run away? I said controlled abruptly. Like by dropping out the generator field contactor. Control is to regulate or restrain, prevent is to keep from happening. No Issue... It works that way..

No comments on "EMD's earliest attempt at wheel slip control" or the "IDAC correction levels"??? No Comment

And while you're at it, how about educating me on "ROTFLMAO"? Haven't seen that before. "rolling on the floor laughing my ass off"
You hit the nail on the head and I found it amusing. I associated OV with excessive train speed.

No flame thrower needed....

  by Nelson Bay
 
OK. Thanks! We're all happy now. I think I'll go roll on the floor for a while now.

  by ExEMDLOCOTester
 
Nelson Bay wrote:OK. Thanks! We're all happy now. I think I'll go roll on the floor for a while now.
Enjoy !!!!

  by BlackDog
 
ExEMDLOCOTester wrote:From the date of the last post this discussion looks done but no one has really defined how wheel slip really works. Anyone interested????
I am moderately curious why my SD75 will let one wheel set slip continuously when I am making a hard pull up the hill. I can apply about 30-40 p.s.i. brake cylinder pressure and the squeeling stops, but after I release the brakes that annoying squeeling sound starts again. The only conclusion I can come up with is to re-true the wheel, to grind those pesky flat spots down. Is this indeed a labor saving option so that the locomotive doesn't have to be removed form service to make its wheels round again? :wink:

  by GOLDEN-ARM
 
Don't do that, Black Dog. That's the "wheel creep" I mentioned. If a wheel is experiencing a limited loss of traction, it is allowed to "run-free" at a speed slightly higher than that, of actual train speed. This is done, until the wheel that is creeping, is able to regain traction again, and the "singing" stops. It's a normal funtion, and sometimes it's sound is pleasing, like a whistling sound, or a finger running on the rim, of a crystal glass. Sometimes, it's like nails on a chalkboard, and aggravating. Either way, the loco is functioning properly. Try sanding, and wait for it to end, and be sure you are wearing your ear plugs, while operating. Regards :wink:

  by ExEMDLOCOTester
 
When we were doing the wheel creep testing on the first GP60 using a consist for a load, the RR Engineer wanted to do exactly the same thing, apply the brakes to stop a potential runaway motor. His comment was that RR Engineers won't wanna listen to that all day... :-)

  by GOLDEN-ARM
 
Hmmmmm. Music to my ears, at least. I know the maximum power is being layed to the rails, with the creep and it's whistling tunes. If I had no creep, I would really suspect, that power was not being fully applied. Very true, at high throttle/amps, and low speed. Sand, sand and more sand, it the only thing to do. (some locos cut off the ability to sand, though, over a set speed. DB is an exception, for this, though) You gotta believe, they're creeping for a reason........ :wink:

  by Nelson Bay
 
ExEMDLOCOTester wrote:When we were doing the wheel creep testing on the first GP60 using a consist for a load, the RR Engineer wanted to do exactly the same thing, apply the brakes to stop a potential runaway motor. His comment was that RR Engineers won't wanna listen to that all day... :-)
Had an engineer tell me he loved hearing the super-series wheel creep song. He said it drowned out the noise created by the snoring head brakeman.

  by UPRR engineer
 
If your new to this topic/post read threw it
Jay Potter wrote:
The answer is that I just finished writing an article for TRAINS magazine about CSXT's AC-traction program; all of the issues that I've been discussing here are also discussed in the article; and everything in the article was approved by CSXT, EMD, and GE before it went to the magazine........

Cover storyCSX'S mountain climbers To scale the stiffest grades east of the Rockies, CSX needed a modern breed of locomotives. GE and EMD delivered Jay Potter
Image


Anyone read his article in Trains a few months ago? Motocross magazines aint far from theses magazines, saw the "Jay Potter tags along with CSX" on the cover with a picture of a couple units and figured id get a good laugh. Two thumbs down from me on his article, i knew it was gonna read like his posts here, word for word and almost as bad as the company hand-outs and the locomotive manuals. Alot of old information from a few years ago, to along time ago and nothing about how it was to tag along. Six or seven pages of crap. Dont know if Jay still slinks around here or not..... I did end up buying it a few months ago when i saw it, didnt get around to reading it till last night while i was at work. Trains magazine hasnt changed since the last time i picked one up about twelve or thirteen years ago, could have swore those were the same articles i read from a few years ago.

  by ExEMDLOCOTester
 
This is gonna be interesting....
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