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Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work. |
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#1
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air compressor on new amtrak locomotives
I was at the local ice cream place that is adjacent to one of the local
train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon |
#2
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air compressor on new amtrak locomotives
In article ,
Jon Elson wrote: I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon Don't know about the locomotives, but can I suggest posting this question over in alt.railroad as well... some pretty sharp train buffs are there. Good Luck! Erik |
#3
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air compressor on new amtrak locomotives
On 2010-06-14, Jon Elson wrote:
I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? I personally think that it is very smart to run the train's compressor from an electric motor. After all, the compressor needs to run only very intermittently, to charge the braking system and such. No idea on constant 60 Hz from the main motors, but if this is done, I would think that it is fantastic for a passenger train that needs a lot of auxiliary power. i i |
#4
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air compressor on new amtrak locomotives
I think the explanation is that the diesel engines aren't used for motive
power, instead, they drive generators (alternators?) that in turn power electric motors for motion, by way of motor drive circuitry. That's the way I've heard it explained anyway. Dunno about the air supply. -- WB .......... "Jon Elson" wrote in message ... I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon |
#5
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air compressor on new amtrak locomotives
"Jon Elson" wrote in message ... I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon From http://science.howstuffworks.com/diesel-locomotive.htm This 270,000-pound (122,470-kg) locomotive is designed to tow passenger-train cars at speeds of up to 110 miles per hour (177 kph). The diesel engine makes 3,200 horsepower, and the generator can turn this into almost 4,700 amps of electrical current. The four drive motors use this electricity to generate over 64,000 pounds of thrust. There is a completely separate V-12 engine and generator to provide electrical power for the rest of the train. This generator is called the head-end power unit. The one on this train can make over 560 kilowatts (kW) of electrical power. See also http://en.wikipedia.org/wiki/Diesel_locomotive about 1/2 way down "Propulsion system operation" Art |
#6
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air compressor on new amtrak locomotives
"Artemus" wrote in message
... "Jon Elson" wrote in message ... I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon From http://science.howstuffworks.com/diesel-locomotive.htm This 270,000-pound (122,470-kg) locomotive is designed to tow passenger-train cars at speeds of up to 110 miles per hour (177 kph). The diesel engine makes 3,200 horsepower, and the generator can turn this into almost 4,700 amps of electrical current. The four drive motors use this electricity to generate over 64,000 pounds of thrust. There is a completely separate V-12 engine and generator to provide electrical power for the rest of the train. This generator is called the head-end power unit. The one on this train can make over 560 kilowatts (kW) of electrical power. See also http://en.wikipedia.org/wiki/Diesel_locomotive about 1/2 way down "Propulsion system operation" I think technically they're called "diesel-electric" locomotives. 560 kW is a lot of toasters!! The hp of diesel-electrics varies from 330 hp (used for the "work trains" in subways) to 6,600 hp behemoths, that are so large they can't navigate certain areas of track. 3,200 hp is indeed a good-sized locomotive. The diesel-electric strategy greatly simplifies the mechanicals, and gives very sensitive control of the traction motors, AND allows the electric motors to brake regeneratively (produce electrical power), altho this regenerated power is not always utilized but is often bled through gigantic banks of iron resistors, which can glow red hot under heavy braking. The steel wheels alone of these locomotives are proly thousands of pounds each, as the wheels on bitty subway cars (NYC) weigh 700-800 lbs each -- no axle, no bearings, just the wheel.. History channel had this guy, a railroad conductor in the NE, do a train reality show, which was really perty inneresting, if you could get past his own personal issues/drama. They might have some shows archived, altho I'm sure they're more innerested in $29.95 for each dvd. -- EA Art |
#7
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air compressor on new amtrak locomotives
On 06/13/2010 06:35 PM, Jon Elson wrote:
I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? If you're generating a 60Hz three-phase rail anyway, a switch to a motor is a heck of a lot easier to design, manufacture and maintain than a shaft to distribute power and a bunch of clutches to turn it on and off. -- Tim Wescott Control system and signal processing consulting www.wescottdesign.com |
#8
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air compressor on new amtrak locomotives
On Sun, 13 Jun 2010 20:35:02 -0500, Jon Elson
wrote: I was at the local ice cream place that is adjacent to one of the local train tracks. The Amtrak pulled up to exchange passengers at the nearby station. A bit after it stopped, I heard a very familiar and unexpected sound. It was a large air compressor driven by a 60 Hz 3-phase motor. I'd guess from the sound it very well could be a Quincy, and I'd guess maybe 15-25 Hp 4-cyl 2-stage, with pneumatic unloaders. Anyway, it struck me as just a tiny bit odd they'd use an electric compressor, as they have mechanical power available off the Diesel engine. I also noticed the Diesel didn't seem to change speed when the train accelerated, so I'm guessing they run a single engine at 60-Hz synchronous speed all the time, so they can distribute 60-Hz power for air conditioning, etc. to the coaches. So, no aux engine for the non-traction power. Anybody know anything about this? Jon I've heard similar on "the tube", the London underground. |
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