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How electric trains work and why they make interesting sounds [video]

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Re: How electric trains work and why they make interesting sounds [video]

#31

Post by 1970-01-01 »

theideaofcoffee wrote: post #13

As much as I love the futuristic and sophisticated sounds that electric traction drives make as compared to their fossil-fueled counterparts, I do think that the driving and control systems that actually generate the PWM waveforms that are sent to the motors are even more interesting. Huge, massive IGBTs weighing a kilo+ each chopping up hundreds of thousands of joules/s of energy without destroying themselves, curre…

Very early EVs (GM's EV1 and then a few other GMs) used banks and banks of water cooled IGBTs to spin the motor.

Re: How electric trains work and why they make interesting sounds [video]

#32

Post by gambiting »

rootusrootus wrote: post #25
Loughla wrote: post #23

Earlier quoted context omitted.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

What would you say the bad part is for a BEV? Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.

I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card).

But I'm also perfectly happy to admit that it's fine and doable just requires adjustment of expectations, and even the charging network thing I'm sure has solutions if you plan beforehand.

Re: How electric trains work and why they make interesting sounds [video]

#33

Post by spockz »

gambiting wrote: post #32
rootusrootus wrote: post #25

Earlier quoted context omitted.

What would you say the bad part is for a BEV? Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.

I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card). But I'm also perfectly happy to admit that it's fine and doable just requires adju…

I got the tip from other BEV users for charging in Germany to go off the highway and find something like a shopping center/mall. There they had always plenty fast chargers and something convenient to do as well. Their built in navigation showed them the way. (This was bmw, not Tesla.)

Re: How electric trains work and why they make interesting sounds [video]

#34

Post by theideaofcoffee »

rwmj wrote: post #27
theideaofcoffee wrote: post #13

As much as I love the futuristic and sophisticated sounds that electric traction drives make as compared to their fossil-fueled counterparts, I do think that the driving and control systems that actually generate the PWM waveforms that are sent to the motors are even more interesting. Huge, massive IGBTs weighing a kilo+ each chopping up hundreds of thousands of joules/s of energy without destroying themselves, curre…

Photo on Wikipedia: https://en.wikipedia.org/wiki/Insulated-gate_bipolar_transis... Are they manufactured using regular silicon lithography? You'd think when making something so large you could just mix up the chemicals instead.

From what I understand, mostly yes. They are still built up layer-by-layer with standard litho techniques, with pattern masks, ion implantation for the p- and n-type layers, etching, CVD to deposit insulation material (for the 'insulated gate' part of the device). Though they don't have to be nearly as precise, as I understand it as something more sophisticated, like a cpu, they still need to lean on those to make it chooch.

Re: How electric trains work and why they make interesting sounds [video]

#35

Post by bgnn »

rwmj wrote: post #27
theideaofcoffee wrote: post #13

As much as I love the futuristic and sophisticated sounds that electric traction drives make as compared to their fossil-fueled counterparts, I do think that the driving and control systems that actually generate the PWM waveforms that are sent to the motors are even more interesting. Huge, massive IGBTs weighing a kilo+ each chopping up hundreds of thousands of joules/s of energy without destroying themselves, curre…

Photo on Wikipedia: https://en.wikipedia.org/wiki/Insulated-gate_bipolar_transis... Are they manufactured using regular silicon lithography? You'd think when making something so large you could just mix up the chemicals instead.

I don't thik they're produced with the same process as CMOS, but I bet some photolithography is involved.

Re: How electric trains work and why they make interesting sounds [video]

#36

Post by thatfrenchguy »

gambiting wrote: post #32
rootusrootus wrote: post #25

Earlier quoted context omitted.

What would you say the bad part is for a BEV? Personally I hope to never drive another gas-powered vehicle, hybrid or not. I'm very much addicted to the convenience and performance of modern BEVs.

I drive across Europe few times a year and covering 800 miles in one day is difficult to do in almost every BEV, maybe with the exception of Teslas. Also I had to deal with chargers in Germany a few times and it's been a pain every time(the classic - charger requires an account, the account only accepts german-registered payment card). But I'm also perfectly happy to admit that it's fine and doable just requires adju…

I mean, you can use Tesla chargers with any car these days in the EU?

Re: How electric trains work and why they make interesting sounds [video]

#37

Post by Lwerewolf »

gambiting wrote: post #24
Loughla wrote: post #23

Earlier quoted context omitted.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

I have a PHEV and I genuienly believe this is the best combination of both, it's so practical with upsides of both drivetrains, but also let's not kid ourselves - PHEVs are vastly more complicated than either just plain ICE or EV cars, you have a lot more stuff that can go wrong. I deal with it by just buying extended warranty for as long as they let me lol, but it's definitely a concern with them.

The Prius and other HSD cars (i.e anything with a power-split device of the Toyota variety - input-split PSD) are some of, if not flat out the most reliable and simple ICE cars. Permanent atkinson-cycle engine, no turbos because there's no exhaust gas pressure to drive them in the first place (and if there was, it'd be an inefficiency to be rooted out), bulletproof starter/generator especially since the ls600h (double-sided cooling of IGBTs >> no usual IGBT packaging degradation-related failure modes - this was NOT the setup on the 3rd gen prius), still a very efficient power transfer from the engine to the wheels (a big percent is still transferred mechanically), etc, etc.

Adding a bigger battery to those isn't a whole lot of increased complexity. The only issue is making a PHEV that has the same performance characteristics in both EV and hybrid mode - not that it hasn't been done. Specifically on HSD cars, the two electric motors combined, or even just MG2 (the "motor") have way more power than you'd assume - they actually function as an AC-AC converter, converting a significant portion of the engine's output power from mechanical to electric and back to mechanical again. It's essentially the way the eCVT works. Therefore, with a battery (and buck-boost converter) that can support such a load, they can propel the car alone way more than adequately - with a speed limit to protect the "generator" from too high RPM, due to the way the HSD works.

Anyways, it absolutely can be done and it absolutely can be way simpler. If it's a case of a typical modern ICE with a big battery and a motor thrown in somewhere that makes it "hybrid"-ish - i.e. all the ICE complexity + the EV "complexity" (minus the classic starter/alternator) - yeah, no thanks.

IMO: Good examples - the Chrysler Pacifica PHEV. Bad examples - C63 AMG (the PHEV version).

Re: How electric trains work and why they make interesting sounds [video]

#38

Post by exabrial »

I do not have perfect pitch (cool party trick), but I can identify all 8 'normal' equal temperament intervals by ear relative to a reference (If you couldn't guess, I play bass, which is a lame party trick).

I was in Austria last year, and a bunch of the trains starting from a standstill had a "gradual acceleration" algorithm for their traction motors. As the drive frequency increased, you could hear the drive motor whine (or maybe it was the inverter?) along with the frequency. It was fascinating, because it played chords as it accelerated: root, 2nd minor, 4th major, 6th minor, octave, then it would pause at the octave and do it again after a few seconds until it reached max power I assume. Each chord had a very faint tritone added to it relative to the chord tonic, so you got this really harmonic pulsing.

After the second course there was too much rail noise to hear what happened, but it was fascinating. I'll try to find a video, I know I recorded it.

Power in Austria/Germany is delivered to trains via a really weird standard too: something like 25hz 27 kV. Leftover standard from 100 years ago.

Re: How electric trains work and why they make interesting sounds [video]

#39

Post by drmpeg »

stackghost wrote: post #19
jimmaswell wrote: post #18

I still find it amusing that most fossil fuel trains only burn it to power a generator, with the wheels run by electric motors. It makes perfect sense with the massive startup torque a train requires, something electric motors are much better at.

The term for that is a hybrid series powertrain. It allows one to optimize the generator to run at a single RPM, which leads to efficiency benefits.

The other problem it solves is the complex transmission required. Diesel-Hydraulic locomotives were built, but were not successful long term. The most famous is the Krauss-Maffei ML4000, built for the Southern Pacific railroad.

https://en.wikipedia.org/wiki/Krauss-Maffei_ML_4000

Re: How electric trains work and why they make interesting sounds [video]

#40

Post by elihu »

Loughla wrote: post #23
euroderf wrote: post #22

Earlier quoted context omitted.

FWIW back in the 80s Mother Earth News had plans for a car that used this principle.

I genuinely believe hybrid cars will be the path once we get the itch for electric cars out of our system. You get all the good parts of each engine type, with less of the bad parts of the other type.

Continuing to burn fossil fuels forever isn't really an option. At some point we'll effectively run out, but before then we'll have caused catastrophic climate change due to our CO2 emissions.

Synthetic or plant-based fuels are plausible options, but synthetic fuels can't compare with battery EVs in terms of energy efficiency, and plant based fuels need crop land that's probably better used to grow food.

Electric vehicles aren't a temporary fad. They're here to stay. Liquid fuels aren't going away either, but I expect eventually they'll be used mostly for military and aviation applications, not ground transportation.

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