Forum Discussion
rhagfo wrote:
You're right.Wes Tausend wrote:
2oldman wrote:
Wow. I had no idea voltage was that complicated.Wes Tausend wrote:
At 4,000 HP, with efficiency of everything at 100%, 4000hp x 746w = 3,000,000 watts/1500a =2,000 volts. Highly theoretical, of course.
if we knew both the amps and rpm, and there was no slippage, we could theoretically calculate the wattage and convert it back and forth to HP, ftlbs of torque, voltage etc:
1 hp(I) = 745.699872 W {P(hp) = P(W) / 745.699872}
I can't imagine the size of cable, or buss bar, that carries that kind of power...let alone the diesel engine size and the generator. I'm so fascinated by big power I hope someone will give me a tour of a modern locomotive.. I've asked, but not yet.
2oldman,
You've definately got the idea now. At higher speeds (40-50 mph), the voltage readout seems to steady out, but even one steady-mph difference changes the ratio between volts and amps... and from memory, every unit is just a bit different. I'm retired now and I can't remember a precise set of matching figures.
Because the Class 1 rail corporations have become so touchy about civilian presence, it became increasingly difficult to invite someone aboard for a tour. The best chance is often on a small short line. These smaller companies are a little more friendly, but most of their equipment is not the newest nor biggest. The very basic electric power transmission principles are exactly the same however, and not unlike the system now found in my wife's hybrid Prius.
I think the root diesel-electric tech evolved out of German hybrid submarines from WWI & II and the need to replace steam. The latest "brushless" AC locomotive US application came out of Siemens and was developed between my home terminal, Mandan, ND and Glendive, MT around 1995. Werner von Siemens founded this vast German company and it was Siemens' engineers that rode and tuned the first 4,000 HP MAC70 experimental locomotives in the US (EMD V16 diesels). Also interesting, Siemens invented one of the first practical electric locomotives of any kind:
von Siemens experimental train, 1879
My company (NP>BN>BNSF), sent us to school in Overland Park (Kansas City), where I became a certified operator in the mid '90's. The school is very thorough in every aspect of railroading and well organized. I'll brag a bit here. In my late 40's, I was worried how well an old man might still learn, since a failure demanded the complete end of my 5 year old job. With this stark incentive, I scored 399 out of 400 in the ABTH/mechanical test and aced out a lot of much younger men. But besides fear, I had a love of machinery, an electrical background and a lot of mechanical experience behind me. Score one for the duffer. :)
Wes
...
How about you two start another thread about the power of Diesel Electric Locomotives, you have done a great job of Hijacking this thread!!!:SWes Tausend wrote:
2oldman wrote:
Wow. I had no idea voltage was that complicated.Wes Tausend wrote:
At 4,000 HP, with efficiency of everything at 100%, 4000hp x 746w = 3,000,000 watts/1500a =2,000 volts. Highly theoretical, of course.
if we knew both the amps and rpm, and there was no slippage, we could theoretically calculate the wattage and convert it back and forth to HP, ftlbs of torque, voltage etc:
1 hp(I) = 745.699872 W {P(hp) = P(W) / 745.699872}
I can't imagine the size of cable, or buss bar, that carries that kind of power...let alone the diesel engine size and the generator. I'm so fascinated by big power I hope someone will give me a tour of a modern locomotive.. I've asked, but not yet.
2oldman,
You've definately got the idea now. At higher speeds (40-50 mph), the voltage readout seems to steady out, but even one steady-mph difference changes the ratio between volts and amps... and from memory, every unit is just a bit different. I'm retired now and I can't remember a precise set of matching figures.
Because the Class 1 rail corporations have become so touchy about civilian presence, it became increasingly difficult to invite someone aboard for a tour. The best chance is often on a small short line. These smaller companies are a little more friendly, but most of their equipment is not the newest nor biggest. The very basic electric power transmission principles are exactly the same however, and not unlike the system now found in my wife's hybrid Prius.
I think the root diesel-electric tech evolved out of German hybrid submarines from WWI & II and the need to replace steam. The latest "brushless" AC locomotive US application came out of Siemens and was developed between my home terminal, Mandan, ND and Glendive, MT around 1995. Werner von Siemens founded this vast German company and it was Siemens' engineers that rode and tuned the first 4,000 HP MAC70 experimental locomotives in the US (EMD V16 diesels). Also interesting, Siemens invented one of the first practical electric locomotives of any kind:
von Siemens experimental train, 1879
My company (NP>BN>BNSF), sent us to school in Overland Park (Kansas City), where I became a certified operator in the mid '90's. The school is very thorough in every aspect of railroading and well organized. I'll brag a bit here. In my late 40's, I was worried how well an old man might still learn, since a failure demanded the complete end of my 5 year old job. With this stark incentive, I scored 399 out of 400 in the ABTH/mechanical test and aced out a lot of much younger men. But besides fear, I had a love of machinery, an electrical background and a lot of mechanical experience behind me. Score one for the duffer. :)
Wes
...
How about you two start another thread about the power of Diesel Electric Locomotives, you have done a great job of Hijacking this thread!!!:S- Ever been to North Platte NE?
2oldman wrote:
Wow. I had no idea voltage was that complicated.Wes Tausend wrote:
At 4,000 HP, with efficiency of everything at 100%, 4000hp x 746w = 3,000,000 watts/1500a =2,000 volts. Highly theoretical, of course.
if we knew both the amps and rpm, and there was no slippage, we could theoretically calculate the wattage and convert it back and forth to HP, ftlbs of torque, voltage etc:
1 hp(I) = 745.699872 W {P(hp) = P(W) / 745.699872}
I can't imagine the size of cable, or buss bar, that carries that kind of power...let alone the diesel engine size and the generator. I'm so fascinated by big power I hope someone will give me a tour of a modern locomotive.. I've asked, but not yet.
2oldman,
You've definately got the idea now. At higher speeds (40-50 mph), the voltage readout seems to steady out, but even one steady-mph difference changes the ratio between volts and amps... and from memory, every unit is just a bit different. I'm retired now and I can't remember a precise set of matching figures.
Because the Class 1 rail corporations have become so touchy about civilian presence, it became increasingly difficult to invite someone aboard for a tour. The best chance is often on a small short line. These smaller companies are a little more friendly, but most of their equipment is not the newest nor biggest. The very basic electric power transmission principles are exactly the same however, and not unlike the system now found in my wife's hybrid Prius.
I think the root diesel-electric tech evolved out of German hybrid submarines from WWI & II and the need to replace steam. The latest "brushless" AC locomotive US application came out of Siemens and was developed between my home terminal, Mandan, ND and Glendive, MT around 1995. Werner von Siemens founded this vast German company and it was Siemens' engineers that rode and tuned the first 4,000 HP MAC70 experimental locomotives in the US (EMD V16 diesels). Also interesting, Siemens invented one of the first practical electric locomotives of any kind:
von Siemens experimental train, 1879
My company (NP>BN>BNSF), sent us to school in Overland Park (Kansas City), where I became a certified operator in the mid '90's. The school is very thorough in every aspect of railroading and well organized. I'll brag a bit here. In my late 40's, I was worried how well an old man might still learn, since a failure demanded the complete end of my 5 year old job. With this stark incentive, I scored 399 out of 400 in the ABTH/mechanical test and aced out a lot of much younger men. But besides fear, I had a love of machinery, an electrical background and a lot of mechanical experience behind me. Score one for the duffer. :)
Wes
...- Wow. I had no idea voltage was that complicated.
Wes Tausend wrote:
At 4,000 HP, with efficiency of everything at 100%, 4000hp x 746w = 3,000,000 watts/1500a =2,000 volts. Highly theoretical, of course.
if we knew both the amps and rpm, and there was no slippage, we could theoretically calculate the wattage and convert it back and forth to HP, ftlbs of torque, voltage etc:
1 hp(I) = 745.699872 W {P(hp) = P(W) / 745.699872}
I can't imagine the size of cable, or buss bar, that carries that kind of power...let alone the diesel engine size and the generator. I'm so fascinated by big power I hope someone will give me a tour of a modern locomotive.. I've asked, but not yet. 2oldman wrote:
Wes Tausend wrote:
at what voltage?
I will guess that each motor draws as much as 1500 amps,
2oldman,
Voltage gets a little tricky. Underway, everything jumps around. I interpolated* the 1500 amps from a DC unit to relate to a more powerful AC locomotive which doesn't have a read out in amps. Unlike the older DC units, the AC locomotive computer screens do read out in main generator (MG) voltage, maybe 2kv at times. If I remember, the KW of instantaneous power reads out in either per axle, or per truck (bogie) of three axles each. The digital readout jumps around a lot when under extreme pull because of constant wheel-slip correction, whereas the old amp guages were slow to respond and therefore gave a very handy average.
I believe the old DC locomotives would hit around 700 volts, but there was no analog volt meter (like the valuable analog ammeter) that would show voltage in real time. When the amps went up on the old DC units, because of a hard start or slowing on hills, I believe the volt output went way down, maybe to 200 VDC.
I kind of get what you are getting at; it seems if we knew both the amps and rpm, and there was no slippage, we could theoretically calculate the wattage and convert it back and forth to HP, ftlbs of torque, voltage etc:
1 hp(I) = 745.699872 W {P(hp) = P(W) / 745.699872}
T = HP * 5252 / RPM
HP = T * RPM / 5252
RPM = HP * 5252 / T
Ignoring slip, if we knew the exact wheel rpms, we could eventually derive voltage. The speedo's are quite accurate on a properly calibrated locomotive. They are adjustable to match wheel size as the steel wheel "tires" wear down. Knowing the exact wheel size, one can calculate fairly precise axle rpm from the indicated speed.
There might be another way to calculate voltage by realising the diesel rpm in "8 Throttle" (about 900 rpm) and supposing all 3000 HP of an old SD40 is "pegged" and being delivered as torque. What again thwarts an exact conclusion is at max torque the traction control is generally periodically cutting power to one or more axles and causing terrible voltage spikes. The max torque is always traction limited so voltage and amps quickly swap back and forth, so more powerful units did this even worse. At slow speeds, a 3000 HP SD40 unit essentially pulled no better than a SD60 3800 HP unit, or a 4000 HP MAC70, if they weighed the same. At high speed against the wind, the 4000 HP wins because it doesn't run out of legs.
The torque of a locomotive is simply directly related to the delivered traction at any given time. The voltage goes up as the amps and torque go down.
* My reasoning was that magnetism, therefore torque, is always directly related to circulating amperage on a similar diameter armature, whether DC or equivalent AC. The amperage doesn't care if it is driven by 1 volt or 20,000. Of course the wiring size, and subsequent number of windings varies by the chosen amps vs available voltage.
And, in keeping with this thread, they'll do it all in reverse too. :)
Wes
...- If this device actually placed the trailer for you that would be something. Fact is you are still controlling the maneuvers your self. NO thanks!
- That's some interesting information Wes. Thanks for posting it!
Wes Tausend wrote:
at what voltage?
I will guess that each motor draws as much as 1500 amps,RedRocket204 wrote:
Wes Tausend wrote:
fj12ryder wrote:
Howard,Wes Tausend wrote:
Riiiiiight. lol
...
If any of you guys want to race backwards, I once backed up at over 40 mph with more than one trailer (across a bridge mind you). And all I needed was my mirrors and a little help to watch for traffic. :)
Wes
...
Well I admit it involved rails. :)
Wes
...
LOL and :C
How much torque do one of those have?
Red,
I'm not sure about the torque, or if there is even a rating. Stuff starts to break or slip before it maxes out.
On the newer units, I've seen a single locomotive develop about 134,000 pounds of traction (at about 900-1000 rpm), and each locomotive usually weighs about 415,000 pounds. I don't think the engines will get any heavier since there is a limit how much contact pressure can be put on the rails with the wheel sizes used. The contact patch is not much larger than the size of a dime, and only that because there is already a slight amount of compression flattening on each of the twelve normally round steel wheels.
Since a single car can weigh up to 280,000 pounds (depending on bridge limits), locomotive traction becomes the major limiting pulling factor rather than torque. Ever since the advent of diesel-electric locomotives (1950's), automatic traction control has been incorporated. If it fails, the errant axle will quietly burn right through the rails in seconds, causing a long delay. Such slippage is not so noticeable to the operator as was the old steam powered units, of which each had it's own operator and made a racket when it slipped. Still, like a drag racer, the steam locomotive operators needed a deft touch.
Traction can only be added by using more locomotives, usually on the head end. In this case, the operator must be mindful of total tractive effort. Each HD coupler knuckle (type F) is limited to 395,000 pounds and protects the rest of the draw bar from damage. They are fairly quick to change, requiring only removing a cotter key to lift a large kingpin out and swap castings. It still takes at least an hour by the time safe arrangements and a new 80# knuckle is on site. Note since the knuckle is only rated for 395k and each locomotive can easily develop 134k, that if three head-end locomotives are loaded in consist, the total added tractive effort rises above 400k and exceeds knuckle separation design. If a train breaks, the trainman (conductor) will not be pleased with his engineer, nor will management. Adding Distributed Power (pusher locomotives at the rear for instance) has eased the danger.
Finally, I think the diesel-generator torque capacity has exceeded the six traction motors combined capacity for some time. We no longer observe draw force by amperage since the computer reads out directly in pounds of tractive effort, but I will guess that each motor draws as much as 1500 amps, and amps are directly related to the magnetic torque the motors develop. With a few size measurements, and some calculations, one might estimate the max torque of each motor. In reality this info no doubt exists somewhere, but I've never seen it. A really bright, well trained Roundhouse employee might see, and remember it from a class somewhere. He would have to love machines like I do.
Wes
...
