Train motor sound - What UK enthusiasts get wrong while Japanese enthusiasts build model VF drives
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- čas přidán 19. 10. 2023
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as a Japanese person who is a big Japanese rail enthusiast, thank God someone pointed this out. Whenever I see the brits write a whole essay about how VVVF's work and the difference IGBT and GTO, or where the sounds come from. They just don't have a clue and it drives me up the wall lol.
An interesting video. The European locomotive Siemens ES64U2 also plays a musical scale when accelerating and braking. Currently, the powerheads of the German ICE-1 trains have also been converted from GTO converters to IGBT converters for future use. This also changed the acoustic frequency of the traction motors after the conversion to IGBT converters when the train started up and accelerated.
They also did that to the SBB Re460
I have come from the future from just before the universe ends and on behalf of the entire internet to award you with the best use of MS Paint in the entire universe and of all time to explain a complicated subject award! Congratulations!
A very well explained video. I used to know a train enthusiast that is pretty dumb too.
I would like to note at 2:20 in some cases with 3-level inverters the power could be at 50%. This is used in cases such as the JR East E231-500 previously used on the Yamanote Line. Many Shinkansen bullet train models also use this inverter circuitry including a few other variations of the E231 and other classes within the Japan Railways fleet. The DB BR 481 also has this capability within it's inverter circuitry from what I understand, however this is never used and operates in a standard 2-level PWM mode. Thyristor and Transistor switches can not be 50% on their own however, and require some form of resistance to create the 3-level effects.
I would assume that there are multiple thyristors to create this, rather than a thyristor being run at 50%
What about the L0 series maglev that will be used on the Chuo line? Does it have a VVVF drive?
@@coastersagaI believe that just uses rapidly switching electromagnets for propulsion
@@coastersaga afaik the latest technology used on the test line was IEGT cycloconverter
@@benolifts Presumably 1 thyristor/transistor for generating voltage >0 and 1 thyristor/transistor for generating voltage
Thanks BENO, this will help me explain to my son, an aircon engineer how VF drives work. Used more and more in the HVAC industry!
Great information, I had always known that the noise was due to the switching strategy but not what the strategy was.
I'm in the same boat. Although I thought they might be also doing something like switching the number of motor poles to keep the switching frequency within acceptable parameters for the transistors/thyristors.
There's a new type of VF drive used in trains SIC-VVVF instead of IGBT, seems like the new VF drives are smaller and more compact
Technically more correct would be MOSFET-VVVF, as that's what's directly replacing the IGBTs.
I"ve heard some rumblings in the last few years about silicon-carbide power electronics - it wouldn't surprise me if they're making a debut in the mass market by now.
@@gorak9000they are in some electric cars like teslas
@@gorak9000 The SiC VVVF is already on the new Japanese trains...and also for example Bombardier (Alstom), the SiC Mitrac, audible in Singapore and Stockholm.
While visiting Austria a few years ago, I heard similar acceleration noises from the ÖBB locomotives. Those were mostly from the Railjet trains.
yes, we use the siemens taurus locomotive for the railjet, and it has a distinctive startup sound, "the tone ladder". I've noticed it when standing by a departing trains, and it seems to stay at a fixed sound after a few seconds.
2:33 Only class AB radio's are doing this, the more common class D radios use PWM
I had a dream where i was on a vintage subway train that had an epic sounding loud VF-drive that sounded similar to the first japanese VF-Drive you showed but instead of musical scales it played a few notes from Justin Bieber's song "Baby"
Many thanks for that, it's explained it very nicely.
Damn, these Japanese make me want to go back to Austria and those wonderdful 1016 and 1116 Taurus locos \m/
The Keikyu 1000 series rolling stock used to have propulsion systems from Siemens too I remember (the one in this video)
I remember seeing those japanese videos. They are so cool
Nice explanation. I'm impressed. 👍🏻
I am inclined to believe this explanation much more. For many years I really struggled find an exact explanation on why Singapore's Alstom Metropolis C751A, which on specification says repeatedly stated that it runs on Alstom Onix IGBT-VVVF, sound nearly identical the London 1996TS which run on GTO-VVVF. Any other explanation offered previously would logically implied that the C751A is GTO-VVVF, which it isn't.
I think they retired the last of the Keikyu 2100 VVVF trains recently. The cute thing is, they were originally GTO, but the replacement controllers were IGBT.
no it wasnt even recently it was ages ago. They more recent were the N1000 series
I like the sound that 1959 stock made. As a much older electric technology. I assume that tube trains newer than 1996 stock don't have pulsing motors, but I haven't been to London for years. Nb a new genre of electrical videos has come out recently from Japan and South Korea - overvolting toys!
All modern trains, electric cars, electric buses, E scooters, and pretty much all traction motors use the method described in this video. Although in smaller motors the carrier frequency would be so high that it never reaches the stage where it has to switch to pattern mode.
@@benolifts What about using a pure sine wave oscillator?
@@coastersaga It is not possible. Think of ohms law. Any part of a circuit that is resisting current is dissipating power. Power can not simply be resisted or turned down like a volume control. The motors are large. A lot of current is passing through them. Large amounts of current can not have the flow of current impeded without huge amounts of heat being produced. The only way current could be resisted is by having motors in pairs and switching between series and parallel, or by using huge heat dissipation resistors, which is what old DC trains used. But with VF drives and AC motors, the output frequency has to be changed. The only possible way is by PWM, so the motor is switched on and off at a very fast speed to create an average voltage.
Is the limiting factor on transistor/thyristor switching frequency due to the time to go from 0% to 100% or 100% to 0% actually being non-zero and NOT possible to reduce proportional to the desired switching frequency, resulting in the transistors/thyristors actually spending some time in a partially resistive state, and the proportion increasing as the switching frequency increases, thereby causing them to overheat if switched too fast?
I would guess that switching too rapidly would also cause eddy currents in the windings and associated materials interacting with the magnetic field, and these would also generate heat without doing useful work, like in a transformer that is fed with too high a frequency (for which its lamination is not fine enough) -- although since as shown in the oscilloscope trace, the current to the motor is partly smoothed out, it's probably the overheating of the power electronics that will usually get you first.
Your first paragraph is 100% correct. It is the time spent on when neither 0% or 100% which is the issue, so as the motor speeds up the pattern as to be reformed into simpler patterns at set intervals to reduce the number of switching states.
With your second paragraph, its actually the opposite that's true. The faster the switching frequency that more accurate the sine wave, so the non desirable currents are in the motor. A lot of smaller motors in industry nowadays have the VF drive switching set to 10,000hz.
@@benolifts So in other words for the second part, the greater accuracy of the sine wave more than makes up for the tendency of the higher frequency to make eddy currents?
As this on the topic of converterts.
Do you repair ac/dc converters or do you know anybody who does
the Japanese are just another level, another league.
So, it is possible to make an electric car, that has shifting in VF drive?
And it could be made in hearing range frequencies.
For those who straight-pipe their exhaust, they could remove the noise filter to make it louder.
Toyota Prius does this. You have to listen carefully as it is doing it at quite a high frequency. 0-20mph is at pure PWM, then 20 to 45mph is using 3 different pattern based PWM. The motor has a top speed of 45 mph, then the power split transmission's CVT system diverts more power to the engine and the motor's speed is held by the CVT to stop it over speeding.
Older electric trains have better traction sound including the Class 323, Class 465 which have been modified with Hitachi traction motors and of course the Jubilee Line 1996 Stock built by Alstom.
Even the newer ones also have epic traction sound like the Class 357, Class 375, Class 376 and Class 377 Electrostars built by Bombardier.
Some 465s still have their original motors
Hey Austin this is guys
Hey guys, beware of misinformation.
Hey guys this is surfy
You would like the plaxton president I rode the other day the VF was very loud
Plaxton president doesn't have a VF drive. Well maybe the fuel pump could possible be on some sort of drive controlled motor, but you wouldn't be able to hear that.
@@benolifts I have a video of it somehow it’s on my channel
@@benoliftsI found out what it was it was probably the gearbox
To put it very simply, the audible sound comes from the stator of the motors which react to the received switching frequency.
Most traction systems using inverters to manage current inputs to the motors use modulation starting with a PWM (asynchronous), then synchronous cutting schemes (SHE 7, SHE 11 etc.)
what I didn't get is, that when the pulse is cleaned say from 10 pulses to 5 pulses per cycle, why does not the output frequency drop? Say the output freq can stay at 10Hz when the pulse is lowered to 5 per cycle and increase as pulses increase again, why didn't it just use 5 pulses to output that 10Hz in the first place?
The issue is a thyristor must never resist current. A thyristor must only act as a switch. It can not be a resistor. Heat dissipates at the point of resistance (ohms law) so the thyristor must do a clean switch between off and on. However, as it is not a perfect world, the change from on to off is not quite instant, there will be a slight moment (just a nano second) when it isn't a clean switch and is between on and off states, at this point heat is dissipated. On pattern mode as the output frequency speeds up the switching also speeds up with the pattern. This means that the thyristor changes state more and more often. Due to this the number of nanoseconds where the thyristor is neither on or off increases. This is the reason why the pattern must reform with less pluses. The reduction of pulses when changing from, lets say, 7 per half cycle to 5 per half cycle means less accuracy on the artificial sine wave. However the frequency of the sine wave is not affected.
Anyone ready to tag Armstrong Powerhouse?
I am Having a blast with this 100% unadulterated autistic model train power train rant.
What language is the speaker using?
How do you mean?
@@benolifts sorry, I meant accent, not language
@@mariog1051He's from the UK, so he's British
@@mariog1051 I would describe my accent as a mix of British RP English, British Chav English and British Autistic English.
First
Arriva
Stagecoach
JR
Rapid Express
Inyong Napakinggan ang Kabuuan ng GMA Super Radyo DZBB...
*SUPER BALITA!!!*
Stop speaking alien language