Yes it’s true, EMD is building SD80ACes, though the current batch is for export only. I wonder what the SD80ACe's hp rating is since the SD80MAC was 5,000hp.
And I heard on another forum that these SD80ACes are only tier-1 compliant, which if true means EMD would have to do modifications to make a tier-3 SD80ACe. IMO, I doubt any north American class 1s would buy the 20-710 SD80ACe since they're content with 16 cylinder EMD and 12 cylinder GEs and are acquiring more of them, even though both NS and CSX roster a handful of SD80MACs.
http://www.railpictures.net/viewphoto.php?id=384479&nseq=1
Its tier 1 for two reasons: a. its going to Australia and B. With judicious tuning they can maximize the fuel efficiency if they don't have to worry about the NOx emissions. Thermodynamic efficiency is determined between the maximum cycle temperature and the minimum. To reduce NOx everybody has to reduce the maximum temperature by several different methods. If you remember that an EMD engine is 20 or 16 one cylinder engine connected by a common crankshaft mounted in a suitable frame. The only problem might be tweaking the turbocharger. So for domestic use the V20 710 is or will be tier 3.
The SD80ACe's were sold to Vale do Rio Doce, the Brazilian mining concern. Are they being assigned to EF Carajas (5'3" gauge) or EF Vitoria a Minas (meter gauge)?
The technical data states that they are 5'3" gauge.
Ira
I found another photograph of the SD80SACe.
On December 22nd Progress/Caterpillar moved three more Vale SD80ACe’s from the plant, this time not on flat cars, but on temporary trucks to Stratford, ON for storage. Included in this move were primer coated Vale C-322-4 (104 - anti-climber chalked C322-4; but nose marked 5E); C322-5 (105 - anti-climber chalked C322-5; but nose marked 4E) on their own trucks, and C322-7E (107) on KRL flat 70989.
SD80ACe spotting features:
- The engine room has 10 doors (8 on SD70ACe) - one per cylinder per side of the engine (total of 2o cylinders/engine room doors).
- The radiator wings are larger as well - there are 9 doors under the radiators on the SD80ACe, 8 on an SD70ACe and hree radiator fans instead of two on the SD70ACe.
- Also 12 handrail stanchions instead of 11 as on SD70ACe.
Lyon_Wonder Yes it’s true, EMD is building SD80ACes, though the current batch is for export only. I wonder what the SD80ACe's hp rating is since the SD80MAC was 5,000hp
Yes it’s true, EMD is building SD80ACes, though the current batch is for export only. I wonder what the SD80ACe's hp rating is since the SD80MAC was 5,000hp
I've read that theses units are rated at 5,500HP,however that may be Gross Engine power rather than the Net power rating commonly used in North America..
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
The SD80ACe is 5300 THP under all service conditions.
sd80ace The SD80ACe is 5300 THP under all service conditions.
Is that at 950 rpm?
M636C
M636C sd80ace: The SD80ACe is 5300 THP under all service conditions. Is that at 950 rpm? M636C
sd80ace: The SD80ACe is 5300 THP under all service conditions.
Good question, but I hope not! If a 16-710 can do about 4500 BHP at 900 RPM, then the 20-710 should be good for 5400 or so THP.
I remember talking to the EMD engineers when Conrail was getting the SD80MACs and asking if a 5500 THP rating, that would give them the same per cylinder output as the SD75s they were building for the ATSF, was possible in the future. I got a "probably".
-Don (Random stuff, mostly about trains - what else? http://blerfblog.blogspot.com/)
oltmannd M636C: Is that at 950 rpm? M636C Good question, but I hope not! If a 16-710 can do about 4500 BHP at 900 RPM, then the 20-710 should be good for 5400 or so THP.
M636C: Is that at 950 rpm? M636C
But it can't... That's the whole point....
The SD70ACe gets 4300HP into the alternator at 950 rpm (so does the SD75...)
Horsepower is pretty much irrelevant when talking about locomotives since it is turning a generator. Tractive effort is what defines a locomotive. You can have the same engine and change wheel sizes, traction motors, generators, and gear ratios and get a wide variety of traction effort ranges. Also upgrading the electrical from DC to AC will give you a big increase in tractive effort.
Many boats do use the same engines as locomotives especially the 645. Horsepower is totally relevant when talking about a boat engine since it is not turning a generator and is constant with its applications.
M636C oltmannd: M636C: Is that at 950 rpm? M636C Good question, but I hope not! If a 16-710 can do about 4500 BHP at 900 RPM, then the 20-710 should be good for 5400 or so THP. But it can't... That's the whole point.... The SD70ACe gets 4300HP into the alternator at 950 rpm (so does the SD75...) M636C
oltmannd: M636C: Is that at 950 rpm? M636C Good question, but I hope not! If a 16-710 can do about 4500 BHP at 900 RPM, then the 20-710 should be good for 5400 or so THP.
Thanks. Didn't know...
Thomas 9011 Horsepower is pretty much irrelevant when talking about locomotives since it is turning a generator. Tractive effort is what defines a locomotive. You can have the same engine and change wheel sizes, traction motors, generators, and gear ratios and get a wide variety of traction effort ranges. Also upgrading the electrical from DC to AC will give you a big increase in tractive effort. Many boats do use the same engines as locomotives especially the 645. Horsepower is totally relevant when talking about a boat engine since it is not turning a generator and is constant with its applications.
No. HP is completely relevant. A locomotive is a constant HP machine above minimum continuous speed. In fact, HP = TE x speed/308 (plus or minus a bit)
Don, or any other railroad people, can you explain to me Minimum Continuous Speed (MCS)?
My understanding is that the tractive effort is almost directly proportional to traction motor current, and this is true both for AC and DC? And traction motor current makes heat that seeks to destroy insulation and motor windings, were it not for the traction motor blowers trying to dissipate that heat? And the Maximum Continuous Tractive Effort (MCT) is determined by those considerations.
Suppose a locomotive was lugging up a hill at its MCT (max tractive effort without going into short-time rating) and at its MCS (minimum continuous speed) with the throttle in Notch 8. Suppose it started to slow down from MCS owing to some increase in gradient or train resistance. On a modern unit, would not the microprocessor engage horsepower limiting so the locomotive would continue to deliver its MCT below the minimum continuous speed (MCS), or in the absence of the microprocessor module, could not the engineer watch the ammeter and make a throttle reduction that would hold tractive effort at MCT while slowing down?
Or am I missing something?
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Paul Milenkovic Don, or any other railroad people, can you explain to me Minimum Continuous Speed (MCS)? My understanding is that the tractive effort is almost directly proportional to traction motor current, and this is true both for AC and DC? And traction motor current makes heat that seeks to destroy insulation and motor windings, were it not for the traction motor blowers trying to dissipate that heat? And the Maximum Continuous Tractive Effort (MCT) is determined by those considerations. Suppose a locomotive was lugging up a hill at its MCT (max tractive effort without going into short-time rating) and at its MCS (minimum continuous speed) with the throttle in Notch 8. Suppose it started to slow down from MCS owing to some increase in gradient or train resistance. On a modern unit, would not the microprocessor engage horsepower limiting so the locomotive would continue to deliver its MCT below the minimum continuous speed (MCS), or in the absence of the microprocessor module, could not the engineer watch the ammeter and make a throttle reduction that would hold tractive effort at MCT while slowing down? Or am I missing something?
You are correct for a series wound DC motored locomotive. With an asynchronous 3-phase AC induction motor locomotive, Motor torque is a function of traction motor slip. An AC locomotive can maintain maximum TE from near zero speed until either maximum applied voltage or maximum supplied power frequency is reached. Once either one of these factors cannot increase then AC motor speed cannot increase without a decrease in motor torque.
oltmannd Thomas 9011: Horsepower is pretty much irrelevant when talking about locomotives since it is turning a generator. Tractive effort is what defines a locomotive. You can have the same engine and change wheel sizes, traction motors, generators, and gear ratios and get a wide variety of traction effort ranges. Also upgrading the electrical from DC to AC will give you a big increase in tractive effort. Many boats do use the same engines as locomotives especially the 645. Horsepower is totally relevant when talking about a boat engine since it is not turning a generator and is constant with its applications. No. HP is completely relevant. A locomotive is a constant HP machine above minimum continuous speed. In fact, HP = TE x speed/308 (plus or minus a bit)
Thomas 9011: Horsepower is pretty much irrelevant when talking about locomotives since it is turning a generator. Tractive effort is what defines a locomotive. You can have the same engine and change wheel sizes, traction motors, generators, and gear ratios and get a wide variety of traction effort ranges. Also upgrading the electrical from DC to AC will give you a big increase in tractive effort. Many boats do use the same engines as locomotives especially the 645. Horsepower is totally relevant when talking about a boat engine since it is not turning a generator and is constant with its applications.
I have no idea where you got that calculation. According to Wikipedia..."For an electric locomotive or a Diesel-electric locomotive, starting tractive effort can be calculated from the amount of weight on the driving wheels (which may be less than the total locomotive weight in some cases), combined stall torque of the traction motors, the gear ratio between the traction motors and axles, and driving wheel diameter"....
A GP38-2 has the same 16 cylinder engine as a SD40-2. There is no difference at all with the horsepower coming out of the engine driving the generator. Yet a GP38-2 has considerably less tractive effort than a SD40-2 because of the obvious reason of weight of the locomotive and two more axles and two more traction motors.
So going to my point earlier putting a 645 engine or even a modern 710 engine into a GP40-2, GP38-2, GP40, GP15, or other GM locomotive that is not a 12 cylinder or 20 cylinder is going to have little or no effect in regards to tractive effort.
You can argue the horsepower ratings all you want but as said before they really are invalid because the tractive effort is depending less on the engine and more on the locomotives weight, generator, DC or AC electrical, number of traction motors, and number of axles.
The HP = TE x speed/308 applies when the locomotive is operating above the speed where the prime mover can supply enough power to supply maximum continuous tractive effort. This speed is higher for a GP40-2 than it is for an SD40-2, due to the lower CTE on the GP40-2. By 20 MPH, the maximum tractive effort for the GP40-2 and SD40-2 will be the same as the tractive effort is horsepower limited as opposed to adhesion or thermally limited.
The formula for a 100% efficient transmission is HP = TE x speed/375 or TE = HP x 375/speed. The 308 figure comes from assuming an 82% efficiency for the electric transmission.
- Erik
beaulieu Paul Milenkovic: Don, or any other railroad people, can you explain to me Minimum Continuous Speed (MCS)? My understanding is that the tractive effort is almost directly proportional to traction motor current, and this is true both for AC and DC? And traction motor current makes heat that seeks to destroy insulation and motor windings, were it not for the traction motor blowers trying to dissipate that heat? And the Maximum Continuous Tractive Effort (MCT) is determined by those considerations. Suppose a locomotive was lugging up a hill at its MCT (max tractive effort without going into short-time rating) and at its MCS (minimum continuous speed) with the throttle in Notch 8. Suppose it started to slow down from MCS owing to some increase in gradient or train resistance. On a modern unit, would not the microprocessor engage horsepower limiting so the locomotive would continue to deliver its MCT below the minimum continuous speed (MCS), or in the absence of the microprocessor module, could not the engineer watch the ammeter and make a throttle reduction that would hold tractive effort at MCT while slowing down? Or am I missing something? You are correct for a series wound DC motored locomotive. With an asynchronous 3-phase AC induction motor locomotive, Motor torque is a function of traction motor slip. An AC locomotive can maintain maximum TE from near zero speed until either maximum applied voltage or maximum supplied power frequency is reached. Once either one of these factors cannot increase then AC motor speed cannot increase without a decrease in motor torque.
Paul Milenkovic: Don, or any other railroad people, can you explain to me Minimum Continuous Speed (MCS)? My understanding is that the tractive effort is almost directly proportional to traction motor current, and this is true both for AC and DC? And traction motor current makes heat that seeks to destroy insulation and motor windings, were it not for the traction motor blowers trying to dissipate that heat? And the Maximum Continuous Tractive Effort (MCT) is determined by those considerations. Suppose a locomotive was lugging up a hill at its MCT (max tractive effort without going into short-time rating) and at its MCS (minimum continuous speed) with the throttle in Notch 8. Suppose it started to slow down from MCS owing to some increase in gradient or train resistance. On a modern unit, would not the microprocessor engage horsepower limiting so the locomotive would continue to deliver its MCT below the minimum continuous speed (MCS), or in the absence of the microprocessor module, could not the engineer watch the ammeter and make a throttle reduction that would hold tractive effort at MCT while slowing down? Or am I missing something?
I'm taking a bit of a guess about the reason for the Minimum Continuous speed for DC motors - I am by no means a motor expert, though did take a course in electrical machinery. If someone has a more accurate explanation, please feel free to jump in and correct me.
On the armature of a commutator equipped motor, only a few of the windings are carrying current at any given time. This means that the windings carrying the current are generating a substantial amount of heat due to the high current densities in the active armature windings. If the motor is turning at sufficient speed, the heating period is brief enough so that no damage comes to the windings - they will have a chance to cool down when inactive. At below minimum continuous speed, the windings are active for long enough to cause damage to the windings.
On a squirrel cage induction motor, the armature is composed of thick copper bars which can carry a much higher average current than the windings on a DC motor. The torque is produced by the rotating field slipping past the bars, which induces a current flowing through the bars (hence induction motor). To be a bit more correct, the torque is produced by the interaction of the field generated by the stator windings and the current induced in the squirrel cage bars. This slip also distributes the heating in case of a locked rotor.
{Edit} A couple of points about the "bars used in squirrel cage induction motors. One is that they have no need for electrical insulation, which also results in much better thermal conductivity from the inside of the bar to the outside surfaces. The other is that the squirrel cage can be designed to allow for more cooling airflow through the armature than for a DC motor armature.
Erik where you are getting this information is puzzling. The tractive effort of a GP40-2 is never anywhere near what a SD40-2 can produce at any speed. The SD40-2 has a minimum tractive effort of 82,100 and a maximum of 92,000. A GP40-2 has a minimum tractive effort of 54,700 and a maximum of 61,000. Both have EMD 16 cylinder 645E3 engines rated at the same horsepower.
Second as a former locomotive mechanic I can tell you the locomotives engine produces more than enough horsepower to turn the generator at any speed or load. If you look at the technical details you will notice the locomotive has a constant RPM speed at every notch that varies little regardless if it is under load or not. That is why the 645 engine is in nearly all EMD locomotives that required a 16 cylinder engine starting in the mid 1960's up until the 710 engine came along around the mid 1980's. Even with the 710 engine it is nearly identical to the 645 in every aspect except for 710 cubic inches per cylinder instead of 645 cubic inches.
The limitations in tractive effort have had little to do with the horsepower of the engine and a lot to do with how much of a load a traction motor could handle before burning up. With AC technology they have eliminated the problems of burning up a traction motor but are still stuck with the size they can build a traction motor and fit it under the trucks.
The tractive-effort-related limitations on AC-traction locomotives are (1) the ability of the wheels to maintain adhesion at high levels of wheel torque and (2) the levels of mechanical stress that occur when those high levels of wheel torque are produced. At the very low speeds where those levels of torque are most likely to be produced, tractive effort does depend on adhesion, not on horsepower. However adhesion is a function of the regulation of wheel creep. The slower a wheel is rotating, the greater the difficulty of regulating its creep and the greater the risk of stalling if creep is not adequately regulated. Horsepower is relevant, in that context, because an increase in horsepower allows a higher level of tractive effort to be produced for any given speed above the adhesion-limited speed range. Consequently if a locomotive needs to produce a given level of tractive effort to move its train, it is advantageous for the locomotive to be able to produce that level of tractive effort at speeds above the adhesion-limited low speed range.
erikem The HP = TE x speed/308 applies when the locomotive is operating above the speed where the prime mover can supply enough power to supply maximum continuous tractive effort. This speed is higher for a GP40-2 than it is for an SD40-2, due to the lower CTE on the GP40-2. By 20 MPH, the maximum tractive effort for the GP40-2 and SD40-2 will be the same as the tractive effort is horsepower limited as opposed to adhesion or thermally limited. The formula for a 100% efficient transmission is HP = TE x speed/375 or TE = HP x 375/speed. The 308 figure comes from assuming an 82% efficiency for the electric transmission. - Erik
Exactly. It's just physics. Work = force x distance. Power = work/time Speed = distance/time. Put them all together and you get Power = force x speed. (the 375 is just to keep the English units in line.)
The minimum continuous speed is the lowest speed you can go before some practical limit keeps you from using all the HP available. It is typically adhesion or electrical limits of the TMs/MG.
Those who question the formula are confusing tractive effort as speed, where a higher horsepower locomotive can produce tractive effort at speed to accelerate further to a higher continuous speed, with tractive effort at low speed and starting, where wheel slip, dc motor overheating, ac hysterises motor torque slip are the limiting factorsand tractive effort, not horsepower is the main factor.
Thomas 9011 Erik where you are getting this information is puzzling. The tractive effort of a GP40-2 is never anywhere near what a SD40-2 can produce at any speed. The SD40-2 has a minimum tractive effort of 82,100 and a maximum of 92,000. A GP40-2 has a minimum tractive effort of 54,700 and a maximum of 61,000. Both have EMD 16 cylinder 645E3 engines rated at the same horsepower.
Page 762 of the 1980 Car & Locomotive Cyclopedia shows a graph plotting the tractive effort for a GP40-2 with 62:15 gear ratio. The plot starts at 86,000 lb at 5MPH (1147 dbhp), looks like a straight line decrease to 51,000 lb at 12 MPH (1632 dbhp), then another apparently straight line from there to 43,000 lb at 23 MPH (2637 dbhp), followed by what looks to be a constant horsepower hyperbola to a bit over 14,000 lb at 71 MPH (2600 to 2700 dbhp). An SD40-2 with 62:15 gears operating between 23 and 71 MPH will not produce any more tractive effort than a GP40-2, unless the rails are really slippery. The reason being is that the prime mover on both engines is limited to about 3,000 HP at the alternator driveshaft, and the transmission on both locomotives is less than 90% efficient.
At speeds below 23 MPH, the SD40-2 with 62:15 gearing will outpull a GP40-2 with 62:15 gearing.
P.S. dbhp = Draw Bar Horse Power
Well, the horsepower rating of the SD80 ACe has been quoted in a recent Newswire as 3952 HP.
This is obviously wrong, since a 20-710 wouldn't produce 400 HP less than a 16-710.
Clearly it is 3952 kW, 5300 HP as quoted earlier in this thread....
I'm not sure there is any merit in extolling the virtues of either TE or power to the detriment of the other as they are inextricably intertwined. Perhaps the following thoughts are enlightening or entertaining or just simply way off track.
When you can get 180,000lb from only a fraction of a rated HP of 4400 it does, on the face of it, appear to belittle the relevance of power. Especially when you haven't changed the engine since its previous best of 140,000 lb with DC motors. What it really means is that power is 'so powerful' that you don't need much of it to get inpressive TE, but only as long as you have an immovable object to take the reaction.
The tugboat zero speed bollard pull is a case in point where, because it moves water to get a reaction, it needs its full installed power, say 4400HP, to get a pull of 96,000lb (rule of thumb 1.1 tons/100HP).
So the locomotive is impressive because it can pull so hard using only, I'm guessing, about 1/4 of its rating. The power required to do this has always been there just waiting to be tapped more efficiently by better adhesion enhancing tecniques.
Once the train is moving slowly with huge TE and minimal HP it then needs more power, not TE, to validate its whole reason for existence, ie to make money by getting up some speed and going a few hundred miles. Admittedly it is excess TE that accelerates a train but at a given speed the only way to up the TE is by increasing the power from the engine. So if you want to make more money by getting there faster you need more power. That is why trains are made up on a HP/ton basis. The TE required just falls out.
Again, power is 'so powerful' in a versatile way that it allows you to choose any number of combinationsof pull and speed to get over the terrain.
Beware of the much-quoted expression for work done, ie =forcexdistance. This appears to enlist TE as a fundamental quantity. Unfortunately work cannot be done solely as defined because as the force moves so time goes by and you have to talk about power. Alternatively, any distance covered has to have been with some velocity and that also enlists power, TEx velocity = power.
Force and distance are easy concepts because you can see distance and feel force. But when you put the 2 man-mades together nature jumps in with the passage of time and forces the concept of power on us.
Apologies if I tuned into the wrong wavelength here. I'm not a train expert.
Pete1950 directs this correctly. Consider loadmeters show amperage representing one or two moter's draw from the engine/generater. Consider that at starting a train, amperage may get to 1250 (or more).
6-moters at 1250 amps.
Horsepower is 740 or-so watts.
Watts are volts times amperes.
Locomotive generaters max out at about 900 volts, though 600 volts is the advertised rate.
So, solve for 6 moters at 1200 amp's using 600 (or so) volts and look at the HP required to produce 1200 amps, based on 740 watts a horsepower.
Ed Wheelighan explained this to me in '1981 from EMD to the SP Engine Service Training Center during fuel-saving directives.
There is a horsepower difference between the GP38-2 and the GP40-2. It is all the way the engine handles intake air.
The GP38-2 uses two Roots blowers to pressurize the airbox on the engine to provide scavenging air to clear each cylinder of burnt combustion gases in preparation of the next power stroke of the cylinder. Typically around 3 to 5 PSI. Horsepower for traction is 2000 HP Max in the 8th notch of power as long as the wheels are not slipping.
The GP40-2 uses a gear driven Turbocharger....the gears are to provide scavenging air in the airbox when the engine idling or lightly loaded up to notch 4. At notch 5 the turbo comes to life as the exhaust gas stream is powerful enough to drive the turbocharger (which has a one way clutch which engages to start the engine or run it until enough exhaust gas pressure overrides the clutch and spins the turbo faster than the gear drive>). A GP40-2 has two horsepower ratings between 1800 to 1900 HP up to a track speed 20-23 MPH then it increases power to it's maximum rating of 3000 HP. I used to watch the power increase when running TV trains on Conrail on the B&A RR from Boston to Selkirk, NY 4 units would pull 100 pigs (not doublestacks) without a problem.
erikem Thomas 9011: Erik where you are getting this information is puzzling. The tractive effort of a GP40-2 is never anywhere near what a SD40-2 can produce at any speed. The SD40-2 has a minimum tractive effort of 82,100 and a maximum of 92,000. A GP40-2 has a minimum tractive effort of 54,700 and a maximum of 61,000. Both have EMD 16 cylinder 645E3 engines rated at the same horsepower. Page 762 of the 1980 Car & Locomotive Cyclopedia shows a graph plotting the tractive effort for a GP40-2 with 62:15 gear ratio. The plot starts at 86,000 lb at 5MPH (1147 dbhp), looks like a straight line decrease to 51,000 lb at 12 MPH (1632 dbhp), then another apparently straight line from there to 43,000 lb at 23 MPH (2637 dbhp), followed by what looks to be a constant horsepower hyperbola to a bit over 14,000 lb at 71 MPH (2600 to 2700 dbhp). An SD40-2 with 62:15 gears operating between 23 and 71 MPH will not produce any more tractive effort than a GP40-2, unless the rails are really slippery. The reason being is that the prime mover on both engines is limited to about 3,000 HP at the alternator driveshaft, and the transmission on both locomotives is less than 90% efficient. At speeds below 23 MPH, the SD40-2 with 62:15 gearing will outpull a GP40-2 with 62:15 gearing. - Erik P.S. dbhp = Draw Bar Horse Power
Thomas 9011: Erik where you are getting this information is puzzling. The tractive effort of a GP40-2 is never anywhere near what a SD40-2 can produce at any speed. The SD40-2 has a minimum tractive effort of 82,100 and a maximum of 92,000. A GP40-2 has a minimum tractive effort of 54,700 and a maximum of 61,000. Both have EMD 16 cylinder 645E3 engines rated at the same horsepower.
That is the curve for a GP40-2 with Performance Control, which allows it to run safely behind an SD40 at speeds below 22-23 mph. It was an extra cost option from EMD -most roads went for it. GE offered similar - they called it power matching.
But from 23 mph up to about 70 mph, that curve is a constant HP curve. Pick any two points and multiply the TE x speed. You will get the same number for your answer.
Horsepower does count once the train is started and determines how soon track speed can be reached or even can it be reached with a particular load, partiulcarly on a grade. Tractive effort is all that matters at startubg and at low speeds.
Dave, do you have any ball-park numbers for the power required to produce a max starting effort, ie at zero speed?
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