Locomotives
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See MNGopher's thread on locomotives:
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000139#000000
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000139#000000
Those EMD 645 engines are two-stroke diesels, both supercharged and turbocharged (yup), and require a zinc-free SAE 40 lube oil due to some of the bearings having a silver alloy.
They're being replaced by four-stroke engines that will use a conventional SAE 40 diesel lube.
These locomotive engines are medium sized engines. On big engines a man goes into the cylinder on a ladder to mike the liner (up to 98 cm.--38" and a stroke about three times that). You put a crew of men into the crankcase and need a chain hoist to lift a bearing shell. These engines are two-stroke, up to straight 14 cylinders, and 80,000kW--107,000 hp. These have maybe 30 tons of SAE 30 crankcase oil and consume about a ton a day of SAE50 or 60 TBN70 cylinder oil injected directly into oil ports in the liner wall for piston/liner lubrication. They're burning 2.5% sulfur heavy black fuel oil.
Ken
They're being replaced by four-stroke engines that will use a conventional SAE 40 diesel lube.
These locomotive engines are medium sized engines. On big engines a man goes into the cylinder on a ladder to mike the liner (up to 98 cm.--38" and a stroke about three times that). You put a crew of men into the crankcase and need a chain hoist to lift a bearing shell. These engines are two-stroke, up to straight 14 cylinders, and 80,000kW--107,000 hp. These have maybe 30 tons of SAE 30 crankcase oil and consume about a ton a day of SAE50 or 60 TBN70 cylinder oil injected directly into oil ports in the liner wall for piston/liner lubrication. They're burning 2.5% sulfur heavy black fuel oil.
Ken
I wonder if I am the only locomotive engineer on this site?
GM has both two and four stroke engines. The four strokes are only a few years old and produce 6000 HP.
GM's most popular 2 strokes are the 3000 hp 16-645, the 3600 and 4300 hp 16-710s (1050 RPM).
Big HP figures may be impressive, but putting that power to a cold wet greasy frosty rail is more of a challange for the locomotive builder when marketing a new design.
GM has both two and four stroke engines. The four strokes are only a few years old and produce 6000 HP.
GM's most popular 2 strokes are the 3000 hp 16-645, the 3600 and 4300 hp 16-710s (1050 RPM).
Big HP figures may be impressive, but putting that power to a cold wet greasy frosty rail is more of a challange for the locomotive builder when marketing a new design.
The frame twister 6000HP 4-stroke GMs are called MAC90s. M is the cab design, AC is the electrical phasing, and 90 is the model being the 6000 HP version. I like to call the 4300 hp 710/16 (11,360 CID) models MAC43s, but it never caught on.
wow, 6000 hp at 1050 rpm. how much torque does it put out?
the turboprop engines i currently work on put out 4000 hp at 13820 rpm and 1600 lb-ft of torque.
the turboprop engines i currently work on put out 4000 hp at 13820 rpm and 1600 lb-ft of torque.
30,000 foot/lbs at 1050 RPM.
HP= Torque times RPM divided by 5,250.
Peak torque is likely MUCH higher, typical torque slope would give a peak around 45,000 ft/lb at somewhere around 800 rpm. Takes a LOT of grunt to move a train.
Peak torque is likely MUCH higher, typical torque slope would give a peak around 45,000 ft/lb at somewhere around 800 rpm. Takes a LOT of grunt to move a train.
Now let us look at the rolling efficiency of the heavy trains. Can any one guess aproximatly how many horsepower it would take to maintain 36 MPH (60K) on straight level track on a windless 20C (70F) day. The test train will be a 7,000 ft coal, 125 cars, 18,000 tons (36 million LBS), 2 GE AC44 locomotives (4400 net hp each)?
You are assuming direct drive. This engine would be coupled to a large ac generator, which would in turn, drive the wheels via electric motors.
Userfriendly can verify if I'm right here, but I would think that the engine would see a pretty constant RPM. It might be varied for economy, but I would think that on initial start, you would bring it up to full speed and then vary the torque put to the wheels using electrical control.
Yes, the engine drives a generator, not an AC one but DC then the current gets chopped up into AC. Take a look at these rpm and HP figures taken off the top of my head GE ac4400@throttle position:
8+.......4400HP...1050 RPM
8........4100 HP...950 RPM
7........3450HP....950 RPM
6........2750HP....850 RPM
5........2050hp....650 RPM
4........1350 hp...650 RPM
3........900 HP....550 RPM
2........550HP.....450 RPM
1........350HP.....450 RPM
To begin a train moving, advance to the 1st throttle position that moves the train. Tractive effort is a product of HP and speed. For example 2 4400HP locomotives will move a 18,000 ton train with no slack in throttle 3 or 4. To maintain 36 MPH on level track will take aproximatly 5000-6000 HP. Too much tractive effort will break the draft gear, so you can't get too ambitious or in a hurry
.
8+.......4400HP...1050 RPM
8........4100 HP...950 RPM
7........3450HP....950 RPM
6........2750HP....850 RPM
5........2050hp....650 RPM
4........1350 hp...650 RPM
3........900 HP....550 RPM
2........550HP.....450 RPM
1........350HP.....450 RPM
To begin a train moving, advance to the 1st throttle position that moves the train. Tractive effort is a product of HP and speed. For example 2 4400HP locomotives will move a 18,000 ton train with no slack in throttle 3 or 4. To maintain 36 MPH on level track will take aproximatly 5000-6000 HP. Too much tractive effort will break the draft gear, so you can't get too ambitious or in a hurry
Id need the speed/tractive effort curves forthe locos and the weights as ballasted to take a proper guess withthe help of MR davis
GE in Erie PA will supply those figures.
I always loved trains-steam engine trains especially, but diesel trains also. Trains are fun to ride on. The Royal Gorge train is one of the smoothest rides you will ever experience. It is like riding on air. The track apparently was built flat out great and the cars have air suspension. It is like being in a luxury car. The engines date back to sometime in the fifties, but they are still great. Some great train rides in Colorado.
We call them "F.R.N.s".
It's interesting that it's done this way. I would think it would be more efficient to have an AC generator drive an AC motor or DC generator drive a DC motor.
Jay;
Here is a quickie run down on GM's SD90MAC:
4300 HP@1050RPM, 16-710G3C-ES, two stroke
Weight 420,000 lbs, wheel dia 45" fuel 5800 USG
or 22,000L, lube 1560L, cooling water 1200L,
Performance: tractive effort=185,000lbs starting, 147,000@9MPH continous. (adhesion factor =35%)
The 6000 HP 4-stroke does not produce a higher starting tractive effort than the 4300 HP model, but will make 147,000 lbs at about 12.5 mph.
"Inverter: each truck or set of 3 motors need an inverter to create AC from DC" That is a copy righted quote from a GM handout.
Here is a quickie run down on GM's SD90MAC:
4300 HP@1050RPM, 16-710G3C-ES, two stroke
Weight 420,000 lbs, wheel dia 45" fuel 5800 USG
or 22,000L, lube 1560L, cooling water 1200L,
Performance: tractive effort=185,000lbs starting, 147,000@9MPH continous. (adhesion factor =35%)
The 6000 HP 4-stroke does not produce a higher starting tractive effort than the 4300 HP model, but will make 147,000 lbs at about 12.5 mph.
"Inverter: each truck or set of 3 motors need an inverter to create AC from DC" That is a copy righted quote from a GM handout.
jay,
if you used an ac alternator to drive an ac motor, you would need to vary the speed of the diesel in proportion to the speed of the motor, kinda defeats the purpose. they used to use dc traction motors, but the ac ones generate more torque and don't have brushes (which need replacing and you really don't want to have to do this on a regular basis). as a side note, these typically use the back half of a PWM drive like industry uses. a standard industrial varispeed drive takes line ac, rectifies it into dc and then chops it back into ac using IGBTs. i don't know if they have started using vector control on locomotives though.....userfriendly? any idea?
if you used an ac alternator to drive an ac motor, you would need to vary the speed of the diesel in proportion to the speed of the motor, kinda defeats the purpose. they used to use dc traction motors, but the ac ones generate more torque and don't have brushes (which need replacing and you really don't want to have to do this on a regular basis). as a side note, these typically use the back half of a PWM drive like industry uses. a standard industrial varispeed drive takes line ac, rectifies it into dc and then chops it back into ac using IGBTs. i don't know if they have started using vector control on locomotives though.....userfriendly? any idea?
Cheta
Gotta go and earn a crust. Called for 20:30 on a container train.
GM and GE do their electrics differently. I'm not sure if I still have the manufactures handouts or not.
Quickly though, the advantage to the AC motors is that they cannot be stall-burned like the old ones. In other words, no short-time slow speed ratings.
We can lug the ACs down to walking speed if the rail conditions are good.
You know, its kinda funny, but the people who have all the answers are the rail fans, not the guys who work on the railroads.
Your answer is close.
Gotta go and earn a crust. Called for 20:30 on a container train.
GM and GE do their electrics differently. I'm not sure if I still have the manufactures handouts or not.
Quickly though, the advantage to the AC motors is that they cannot be stall-burned like the old ones. In other words, no short-time slow speed ratings.
We can lug the ACs down to walking speed if the rail conditions are good.
You know, its kinda funny, but the people who have all the answers are the rail fans, not the guys who work on the railroads.
Your answer is close.
userfriendly,
had forgot about the problem with low or zero speed high-amp burnout of the comutator ring. all of my experience is in industrial usage, but i took a course on GE drives (the old hybrid ac 6 step units) at the erie, PA plant. at lunch we went over to look at the electromotive classroom, which had one of their new (ok, this was the 80's)digital drive locomotives run out over a pit. was interesting, and our teacher also did the class on the traction motor drives. so we all got the 20 minute short course in locomotives. from the alternator to the traction motors though, the hardware is the same as what i use every day in industrial applications (although not as big). as vector control of drives has become the big thing in the last 5 years, wondered if it had made it to the locomotive electronics yet. same driver section with IGBTs, but gives you finer control of what is going on in the motors.
had forgot about the problem with low or zero speed high-amp burnout of the comutator ring. all of my experience is in industrial usage, but i took a course on GE drives (the old hybrid ac 6 step units) at the erie, PA plant. at lunch we went over to look at the electromotive classroom, which had one of their new (ok, this was the 80's)digital drive locomotives run out over a pit. was interesting, and our teacher also did the class on the traction motor drives. so we all got the 20 minute short course in locomotives. from the alternator to the traction motors though, the hardware is the same as what i use every day in industrial applications (although not as big). as vector control of drives has become the big thing in the last 5 years, wondered if it had made it to the locomotive electronics yet. same driver section with IGBTs, but gives you finer control of what is going on in the motors.
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