horsepower vs rolling resistance
horsepower vs rolling resistance
(OP)
steel wheel on steel rail. horsepower calculation per the attached sketch
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horsepower vs rolling resistance
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RE: horsepower vs rolling resistance
I think there is a railroad engineering forum here as well.
RE: horsepower vs rolling resistance
Check out: http://en.wikipedia.org/wiki/Rolling_friction
The value of rolling friction for a steel wheel on a steel rail is given in the table.
Timelord
RE: horsepower vs rolling resistance
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: horsepower vs rolling resistance
htt
Ted
RE: horsepower vs rolling resistance
Were using metric units over here so I did the calculation and converted to horse power afterwards, this gave me an answer of 0.02245 horse power.
Firstly I took CRF to be 0.0006 for steel on steel which I then multiplied normal force of the wheel to find the force to overcome friction.
To find the power required I simply multiplied the force to overcome friction by the velocity which gave the answer above.
regards
desertfox
RE: horsepower vs rolling resistance
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: horsepower vs rolling resistance
I don't think a 20w motor will do it, but thats whats needed
just to overcome the friction and maintain the existing velocity given for one wheel, what you need to get it started in the first place etc is another question entirely.
desertfox
RE: horsepower vs rolling resistance
RE: horsepower vs rolling resistance
Are we doing someone's homework problem here ?
-MJC
RE: horsepower vs rolling resistance
RE: horsepower vs rolling resistance
Check his profile he as been a member for 4 years I doubt this is homework.
regards
desertfox
RE: horsepower vs rolling resistance
RE: horsepower vs rolling resistance
HP = (22 fpm * 56,000 lb) / 33,000 ft-lb/min-HP = 37.3 HP
rolling friction will decrease this value; dirty environment, defects, grades, etc. will increase it.
RE: horsepower vs rolling resistance
I'd hazard a guess the real answer is somewhere in between!
Perhaps the OP could tell us what he is really trying to do, while I agree that desertfox did answer the exact question as posed, I don't think it is a real world solution.
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: horsepower vs rolling resistance
RE: horsepower vs rolling resistance
The reason dvd got a different number to mine was he didn't multiply the normal force by any CRF.
I agree its not a real world answer it only addresses the amount of power to maintain one rolling wheel in equilibrium. Maybe the op will come back with some more info.
regards
desertfox
RE: horsepower vs rolling resistance
What may not be real world is not including bearing/bushing friction.
Ted
RE: horsepower vs rolling resistance
Cheers
Greg Locock
SIG:Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips.
RE: horsepower vs rolling resistance
"The 18.9-million-lb, 3.5-ft-deep dish takes about 65 minutes to roll outdoors for sunlight and grooming...
...The tray moves over 13 rails using 542 steel wheels, 76 of which are driven by 1-hp motors."
Looks like about 150W will move a 25t railcar, just not very fast.
RE: horsepower vs rolling resistance