Those power ratings that are usually quoted for modern engines, like 4300hp for new EMD units or 4400hp for GE units, is that prime mover power, of drawbar power?
I ask because I have this XLS file made by someone containing technical data for most diesel engines ever made, and for newer EMD units it is specified that 4300 is drawbar power, while prime mover power is 5000hp. Is that incorrect?
thanks
4300 HP is the output of the 16-710G3C-T2 engine.
It is neither prime mover nor drawbar horsepower.
Diesel-Electric locomotives are rated in Nominal Traction Horsepower. In a nutshell, traction HP is the minimum full power available to the traction alternator from the diesel engine. So in rating a new GEVO at 4400 HP, GE is saying that at all times, under full throttle, at least 4400 HP will be availble to the traction alternator.
Generally, both EMD and GE alot an extra 300 HP or so to run the locomotive’s auxiliary equipment, so the net crankshaft HP of the GEVO is around 4700 HP.
The current version of the 12 cylinder GEVO is able to run as high as 5200 Traction HP in long term durability testing, while the current EMD 16 cylinder has pretty much tapped out at 4300 Traction HP.
To find the rail HP, you need to subtract losses from the electrical circut (alternator, traction motors, inverters on AC locomotives, etc) The DC GEVO is running around 91-92% efficient in this regard, while the AC verson is above 94%. So you are looking at 4050 to 4200 rail HP from these models.
To find drawbar HP, you must subtract the power needed for the locomotive to move itself forward at a given speed.
I should add that if the locomotive is not using all of its alotted auxiliary HP, the extra HP will be available for traction. That is why it is called a Nominal Traction rating.