@@faded.0913Define lots? Train inverters have distinct frequency steps to power up, usually just 3, but I can't see this doremi inverter being hugely more inefficient, but yeah, every penny adds up
If I had to guess I would say the engineers had this as an audible troubleshooting tool. You can hear if and when your inverters were acting up without any extra tools. This would also be useful for the driver/conductor or other people in the loop as they could inform someone that some specific train wasn't singing correctly
When I was a kid, I connected a small DC motor to the speaker terminals on a radio and made a very inefficient speaker. If I touched the drive shaft to a surface, I could hear the radio. It worked quite well touching a glass window.
@@eljaibas16 I did it with an MWO transformer, to get electrocuted with the rhythm of the music. It was fun until it got truly scary when I cranked volume too high up and heavy beats came from the music (it was on a somewhat powerful home stereo amp). *Seriously dangerous, do not try it.* But, the transformer was also audibly singing indeed!
One of the most iconic train noises in the UK is the class 323... That uses the stepped gradual wave forms that this inverter used for the second stage of acceleration... Sounds like the train is changing gears
The "Singing Trains" of Montreal Canada were so iconic, that the residents of the city voted to make the sound they made, the new chimes that play when the doors are closing. Even though the vast majority likely had no clue what caused the sounds One model of train in Montreal using the old Jeumont Schneider DC current choppers is still in service, but they were built in the 70s so who knows how much time they have left
Here in São Paulo we had (and still have) trains with a do-re-mi inverter and jeumont Schneider DC chopper, in the case of the do-re-mi inverter we have the CPTM series 3000, and in the case of the jeumont Schneider chopper we had the series 5500 "eletrocarro" from CPTM, the frota C of the São Paulo subway (current frota K of the São Paulo subway) and series 5000/5400 from CPTM "fepasao" the first and at the same time the last Jeumont Schneider chopper in São Paulo and Brazil
@@GabrielVictor-te2sk And actually the only system to use those choppers that wasn't a rubber tired system, and the only other one remaining, since Mexico City replaced the Jeumont equipment in their MP-82 cars...
@@wilfstor3078 remembering that the eletrocarro was retired in 2012, however it had a modernized version called 5550 that operated until 2016, the 5550 as well as the mp-82 of the mexico city metro had its Jeumont Schneider chopper replaced by electronic management equipment, however its original traction engines were maintained (although revised), during the renovation it had its original front (here in São Paulo we call it the front of the trains mask) of 3 stainless steel windshields replaced by a fiberglass front with 2 windshields, the frota c between 2009 and 2014 was modernized, becoming the frota k, just as the 5550 had its original front replaced by one with a modern appearance, was equipped with air conditioning, and had its original jeumont Schneider choppers exchanged for a very silent vvvf and the original DC motors exchanged for AC motors although the rotor of the traction motors remain the same (the original mechanics were maintained), as the traction sound of the frota k is similar to that of its original form, whereas the 5400 is very difficult to show, as only one operates and most were immobilized
The reason for the variable switching frequency is that there is a MINIMUM ON TIME. Another example would be the czechoslovakian class 363 locomotives that had three distinctive switching frequencies 33,1/3Hz 100 and 300Hz. Due to the fact that the thyristors needed forced commutation trough a commutation reactor and cappacitor, they were limited to a minimum turn on time in which they will get a consistent firing of the main thyristor (After firing would stay conductive until the commutation tyhristor takes over to shut the main thyristor) This had one problem. With a fixed Ton you would have a minimum Duty cycle far too large for reasonable starting of the train. Basically the loco would instatnly start to slip and rip off the connection between the cars.. What they they did is that they decreased the switching frequency only for small powers so after reaching a certain time threshold the inverter switched to a different frequency allowind for a much better distributed current draw. After all you need a smaller inductor for a 300Hz pulsed DC to smooth out, than if you had 33Hz pulsed DC The class 363 is an early 1980s design locomotive, incorporating PWM regulation of DC traction motors. The switching was done with thyristors (the OG ones not these newfangled funny GTOs :D ) so they needed to get creative. Minimum reliable Ton (that would guarantee main thyristor conduction) was 0.3ms. This on time at 300Hz would result in a 9% duty cycle right from the starts...that wont do! So what they have done is go trough 3 frequencies. 33 1/3, 100 and 300 Duty cycle as follows 33 1/3 from 0.9% to 3% 100Hz from 3% to 9% 300Hz from 9% to 90% This allowed for a reasonable efficient controlling of voltage, and during the riding stage the use of a 300Hz frequency allowed for a smaller filter inductance to smoothen the current out and consequenty so that the torque is constant instead of being pulsed at 33Hz (funnily the whole thing rattles at this frequency during a run up) incase of the N1000 the motors are asynchronous AC. They modulate the low frequency sinewave into the pulse width. Change of frequency changes the RPM. But asynchronous motors have a voltage over frequency curve. The higher the frequency the higher the voltage, demanding a larger PWM swing. So for full on 50Hz lets say, you need full modulation from 0% to 100% dutycycle. But for 5Hz you need 0% to 10% and this might prove problematic due to the minimum on time of the thyristors. So the simplest solution is to change the frequency of the modulated pulses. Any time you can afford to make the frequency higher you should do it as it increases smoothness of operation and homogenises current flow into the motor windings. I hope this rather technical essay helped clear things why they make this sound..
Why do trains then go to pattern mode at higher speeds? is it for harmonics or switching/ minimum on time. Also why bother keeping the PWM carrier fq low at startup and then raising it with modern VFD inverters?
@@wezdog1 this is an asynchronous thyristor inverter speciffic thing. With a changing modulation freqiency you hit a point when the carrier frequency (the switching frequency) and the mpdulated frequency are gping to multiples of each other. 1/10 1/8th 1/4th 1/2 1/1 2 4 8 10... it cannot be an even multiple. This is due to phase crossing points. It might cause a quirky behaviour where some DC could be let trough and that would cause DC magnetisation of the motor core or utterly abolish the thyristors..
haha the green ones with white lines. I think the English translation of the way they are called is "number trains" idk. 81-717/714 type. I have not heard the new ones make the same sound. At least in Moscow.
In Central EU there are trains that still uses theese. Freight trains, like Siemens Taurus, ect. When an OBB Taurus is departing from our local station, I allways stop, and listen to it, it is so god damn good...
As far as I know, they pick the inverter frequencies to change at low speed to avoid resonance in the circuits - they could pick any ascending frequencies, but why not make it sound nice! I respect the engineers that picked it. It's a really nice touch.
for the 100th anniversary of the ÖBB (Österreichischhe Bundesbahn - Austrias train company), they controlled the inverters of some trains, so that the trains played Happy Birthday
The first AC train motor inverter ever was Helsinki metro M100 stock's Strömberg equipment from 1977. Plenty of YT videos available. The frequency divisors are a series of small primes. The equipment was also used in the Finnish Dr16 engine and the prototype of the gigantic VL86F Soviet engine that unfortunately fell with the Soviet Union.
When braking, energy is returned to the inverter capacitor. Which can explode. Therefore, for safety, this energy must be dissipated using a brake chopper or returned to the electrical network.
4:55 I think that engineer just needed to deal with switching frequency in audible spectrum..so they decided to tune it, instead of let it annoyingly whine...
@@CTSLRailfan I've heard it while standing right beside a locomotive but I never quite caught the sound or heard it in a video. It's very subtle and hard to hear over the engine.
this reminds me of jubilee line, I've always loved the way it sounded, sounds like a car changing gears.. if I was designing an electric sports car i'd definately consider integrating a similar system instead of those fake speaker pumped noises we see nowadays
That, and the Class 465/2 465/9, and 466 used on SouthEastern, have a slightly later technology using continuous variable frequency rather than stepped variable frequency.
Every possible permutation of singing train is used here in the UK, it's great! 😂 I even remember the old resistor bank DC controllers with their clickity clack.
The soul of the car is the sound of combustion, the vibrations and the control you have. EV's have no soul, no matter how much they try those fake sounds. Rimac might have a decent sound that gives it a soul, but will never replace the sound of combustion nor is it as much as exciting
As a developer for multi megawatt inverters that have wide range of different sounds between 1...10 kHz, iam always disapointed from the sound of my EV.
Modern inverter are better in making real sine waves therefore they make less noise and are more efficient. A low power equivalent are stepper motor drivers. Some people played songs on printer or even floppy drives with that.
@@AttilaAsztalosYes, however those are intentional, and done without moving the motor shaft. During actual operation, the brushless motors don't actually make much sound.
The reason the Keikyu N1000 series has those singing motors is that the VFD was manufactured by Siemens. Siemens was known for making "singing" GTO VFDs. Their EuroSprinter (aka Taurus, ÖBB Class 1016/1116) locomotive is a great example of that, and it's one of the most iconic and loved modern locomotives just for that reason alone. 13:04 This sounds like a EuroSprinter locomotive starting while hauling a heavy freight train. I think they used the same inverter, but the motors probably had a different gear ratio in the EuroSprinter, because it is a high speed locomotive (certified up to 230 km/h).
actually, the reason for the switching frequency change even though it is an induction motor is to control the losses during startup and very high slip conditions
When I heard the name of the inverter, I first thought it was a Japanese word, but seeing it spelled out in the description made me remember the musical scale, which made the sound make more sense! Gotta love Japanese humor!
I hear 1000 and I think Shinkansen. I miss that train design. Clearly I ignore the fact you say "N" 1000. You brought back a deep memory I forgot I even had. When I was younger, my father would frequently take me to Japan to visit his side of the family. Hometown on Kyushu Island. But you don't go to Japan without touring Tokyo, and re-visiting the places he moved to when he moved to Toyko area - Yokohama, and Shinagawa. Hearing that sound, that I have not heard for over so _so_ long, brought back a lot of good memories. Thank you. And very interesting video!
We have a train in the UK known as the Class 323 that makes a distinct sound due to originally having GTO Thyristors (made by Dutch manufacturer Holec). Instead of music, they sound more like a racing car going through the gears though. More recently they were upgraded with IGBTs, but these were programmed to produce the same frequencies (since that meant they didn't need to be retested for electrical interference) which means they make the same sounds.
Class 465 BREL used to have these too. Probably an abb gto's
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One of the reasons it does notes is that the fundamental inverter frequency and its harmonics have jump in order to avoid getting into the frequency bands of the audio frequency track circuits.
Finally someone that understands why trains make that sound that actually explains it in plain English. I watched your videos in awe in the past but couldn't understand a word as you spoke Japanese. Now the time has come! 😎
Montreal Metro MR73 -- have Inverter sound too (3 notes). The sound have become so popular that it is use (Replicated) to indicate that the door will close... Then, when the train start (The inverter this time). The most recent Metro units don't make noise anymore.
I guess the DoReMiFa frequencies were chosen simply because anything else would sound weird or wrong or unexpected. With a well defined set of frequencies, the public would always recognize the sound (safety and branding) and not worry about it. And the proper frequency of the inverters can be very easily checked by listening and so a defect may be quickly noticed by accustomed train personnel even without conscious listening.
Thanks alot for the video with the explanation 🙏 I remember this sound from the time, when I traveled first time to Tokyo. And I also recognized it at Vienna. But I had no idea, that they did it on purpose. Maybe I can add a soundcube in my brick built Monorail with this sound 🤗 Greetings from Switzerland Buttermaker
@@erwinkonopka7071 and that makes Poland "like two decades behind on train tech" in what way, fella? ÖBB still run singing Taurus locos in their diagrams.
Thanks for the video. I did had an privilige to travel with that singing train when I visited in Japan. Please also check Helsinki metro M100 series. It is the worlds first VVVF train designed and came into to service in late 70's. It is still in use! I went to school with it in the 80's and later to work with it.
Literally yesterday asked myself that question. Today appears suddenly this vid on my YT feed.... Crazy! Amazing video, Thanks for sharing your knowledge
My favorite use of the system is the variable voltage variable frequency gate turn off equipped Siemens EuroSprinters, most particularly the so called "Taurus" models (ES64U2). Such locomotives are popular for both passenger and freight applications. My favorite rolling stock period.
When I first heard a video of that train I was like this is the coolest thing Ive seen (or should I say heard)...safe to say whoever the engineers were, they were also musicians! Also side note you can kinda tell the technology is older cause there are so many "steps" in the acceleration/deceleration even after the singing part...one of the more modern versions of this idea, the NYC R160B with Siemens IGBT has smoother sounding acceleration (but it also has only a single 400Hz "note" in the low speed area so I totally get it if you don't think it's as cool) Im not sure if this is just me but the acceleration on the R160B makes it sound a lot faster than it is
The Sawtooh PWM cycle is meant to limit inrush current and shake off friction. It just so happens that is makes the do ray me sound. it was the best way to utilize the technology they had at the time.
The ÖBB Taurus has a similar system for their electric system. A student college of mine once told me: "I was always wondering who plays such bad violin sounds all the time, until I realized it's the train" :D
I would say the steps are to keep the power input constant during starting, as the power needs of the motor change because of the need for increased slip during the initial power application, and the steps are there to reduce the CPU need for a smooth sweep, as the original designs used lower speed processors, so offloading most of the power control into discrete power steps was needed, so as to not cause excess slip in the motor and thus poor accelleration, and too fast a ramp would result in a motor stalling. thus the constant steps, so that a driver could keep a constant pull away and not run the risk of a stall, which would mean a stop and a slower ramp up again, and a possibility of the motor generating an overcurrent or tacho feedback error. remember this was originally running likely on aZ80 or similar processor, with large parts being done by other processors as well, and the designers had both limited memory and limited performance. 400Hz was running the GTO devices at the high end of the range, as they, for power devices at the time, needed 2 or more same size power switches for each of the 6 legs of the drive, and GTO devices need you to have a very beefy current source and sink, as you need to turn it on fast, so high current at a relatively low voltage of around 5V on the gate, and turn off you need a current about what the device is conducting, and around -10V, to pull the gate off hard and fast enough to switch off. At least this was better than earlier thyristors, where turn off was done using LCR circuits, and a second equally rated thyristor to pull the anode negative for long enough that the first one would be able to turn off, and then the second one, due to the high power resistor providing it with power, would stay on till the first fired again to turn it off. High static current, high power loss, the GTO made this power use so much lower, at the expense of needing 4 isolated relatively high power supplies, 3 for the upper bridge, and the lower one having a common cathode connection. Instead of 500W of power dissipation now down to under 100W at idle. Add this up per axle and the power use becomes considerable, plus higher frequency, and the ability to do regenerative braking with much less processing power, and you can see why they, and now the IGBT, won out.
Great video! Yeah, I bought one of those industrial fans one time to use for filtering solder fumes at my desk and it is VERY loud lol! It moves a lot of air though
You just haven't ridden in the Ема-502 ... In Japan, trains run for 15-20 years ... meanwhile in Kiev Kharkov and St. Petersburg trains run for 50-60 years xD Waiting to make a rheostat controller for a DC colector motor ))
In the Mexico City Metro, the entire fleet of line 8 is made up of Bombardier NC82 pneumatic trains with 9 cars that also have a characteristic sound when accelerating and braking, considering that they are powered with 750 volt direct current and also uses DC motors.
We had two indoor 100 HP HVAC fans that we installed VFD'S on back in early 1980's and depending on the speed you could hear the odd sound produced by drives several hundred feet away. Place that I retired from had over 500 VFD'S and being they were on drives that used IGBT'S with up to 5,000 Hertz switching frequency only receivers rattling sound on a few of them.
Here in Portugal we have fairly recent trains that make a similar noise, IF i'm not mistaken they are made by Siemens-Bombardier however is well muffled and is hard to tell if it the same type of frequencies.
While most people would consider it noise compared to this, the electric motors in my local metro have a very distinct sound, even after they changed the old trains with the new ones... It just gets into your brain. I would have loved it if you showed the code to make the various sounds...
Funfact We got two trains in Germany that Sounds like N1000 Keikyu BR182(ES64U2) and 424/425/426 EMU If You combine those sounds you get the singing Keikyu train
you can often hear inverter noise from electric cars these days, and most sound like they’re using variable-frequency control modes, which don’t produce pure tones. presumably carrier frequency modulation for EMI reduction - varying the PWM frequency spreads the harmonics out and can significantly reduce high frequency peaks that could otherwise cause interference
I've looked a bit into this and I have a theory for why this sound is: it's not that GTO Thyristors are limited to a few hundred Hz. Basically, when you have an AC motor, be it synchronous or asynchronous, the speed where you have maximum torque is directly correlated to the line frequency of the AC sine wave. The inverters used in trains control the motor with a scheme called V/Hz, where they gradually apply sine wave voltages of ascending frequency, starting very low and gradually increasing the frequency as the motor speeds up. They raise the frequency in discrete steps, this is what makes the "gear shift" sound, which in this case was deliberately made to match a musical scale. There are other more sofisticated control schemes, such as FOC, which calculate in real time the exact optimal current for every coil of the motor in relation to its rotation, such method is used in electric cars and is much more silent. What does change between GTOs and IGBTs are the harmonics in the sound: the inverter can't make sine waves directly, it can only ever turn the power electronic devices fully on or fully off, making square waves. By modulating a high frequency square wave in a certain way and filtering it through a capacitor, you can make a sine wave. GTOs can switch at about 1-2kHz, while IGBTs reach tens of kHz, meaning the GTOs will superimpose additional audible harmonics on the final waveform
The reason for this sound should be something about magnetic field and efficiency at extremely low RPM. Nissan Leaf has stall protection, that if motor is hardly turning it will not use regular high frequency swithcing and will downgrade for lower one, more heard, but more efficient and less heat output at low rpm.
Nice! I live in Austria and I'm used to the sound of the "Taurus" locomotives which is similar, though if I recall correctly, the musically sounding sequence is shorter than in the trains you showed.
The R142 and (some) R160 cars on the New York City Subway system use an Alstom ONIX 800 IGBT system, and play the first three notes of "Somewhere" from the musical "West Side Story" as the train accelerates.
Hi Denki, this is a great video. Thank you. Did you try sending a mail to any of the engineers back in the day to understand the real reason behind it. It could be very interesting to know definitively than seeing so many nice speculations in the comments.
Here in the east of Germany we have now electric trains which are making exactly this sound if they start driving. For us this devices are totally new and Japan have stop working with this, because they have newer motors. Impressive.
A note, I remember a video featuring a crane with some sort of MODERATELY high pitched music music synthesizer serving the purpose of a hazard beeper At first thought, it sounds stupid, and/or janky, but if you do your research It's actually genius. Music is a lot harder to tune out than a repetitive beep
I hear examples of this on Thameslink UK trains, on Amsterdam trams and, most recently, on Prague trams. Interestingly, I haven't yet heard trolley buses making these sounds.
Modern IGBT-Inverters are fully computerised and can play any monotonic tune. The ÖBB Taurus sometimes even plays the austrian national anthem and the german ICE 3 can play the german national anthem in service mode. The only reason why there aren't more trains playing sounds is because adding fun features is not "formal" enough.
Place the fan further from the fins of the heat sink, by adding a length of pipe, to avoid the shearing effect of the blades. This should ,,cure" the noise from the fan.
The engineers choosing sounds that are musical notes is an elegant touch. Thank you both for the video and the translation.
Those were added only as a deliberate easter egg. On some models it was removed later in a firmware update, unfortunately.
@@Stoney3KI can imagine it caused massive performance issues and they wanted to improve efficiency. There's lots of lost energy to produce this
but why?
@@faded.0913Define lots? Train inverters have distinct frequency steps to power up, usually just 3, but I can't see this doremi inverter being hugely more inefficient, but yeah, every penny adds up
I'd prefer if the train were to have a loud V8 powering it 😂
A very good example for a do re mi fa inverter is the Siemens "TAURUS" train used by the Austrian ÖBB train company
They are also used in Hungary by the Hungarian State Railways (MÁV) and Raaberbahn (GySEV) They are mostly called music boxes around the country.
We have the same power train in the metro of Buenos Aires @@zsomborhun8105
The sequence is slightly off key and this drives me crazy! Or am I musically deaf?
Here in Sao Paulo, Brazil, there where some Siemens 3000 trains with do re mi fa inverters too. I remember being very intriged with that noise
@@zsomborhun8105 the Czech Train Service uses it too, although they are owned by the ÖBB so its obvious
If I had to guess I would say the engineers had this as an audible troubleshooting tool. You can hear if and when your inverters were acting up without any extra tools. This would also be useful for the driver/conductor or other people in the loop as they could inform someone that some specific train wasn't singing correctly
When I was a kid, I connected a small DC motor to the speaker terminals on a radio and made a very inefficient speaker. If I touched the drive shaft to a surface, I could hear the radio. It worked quite well touching a glass window.
Same 😅
@@eljaibas16 I did it with an MWO transformer, to get electrocuted with the rhythm of the music. It was fun until it got truly scary when I cranked volume too high up and heavy beats came from the music (it was on a somewhat powerful home stereo amp). *Seriously dangerous, do not try it.* But, the transformer was also audibly singing indeed!
One of the most iconic train noises in the UK is the class 323...
That uses the stepped gradual wave forms that this inverter used for the second stage of acceleration...
Sounds like the train is changing gears
Dutch VIRM trains are making that changing gears sound as well
The "Singing Trains" of Montreal Canada were so iconic, that the residents of the city voted to make the sound they made, the new chimes that play when the doors are closing. Even though the vast majority likely had no clue what caused the sounds
One model of train in Montreal using the old Jeumont Schneider DC current choppers is still in service, but they were built in the 70s so who knows how much time they have left
Dou dou dou!
I was just about to write this
La STM vous souhaite la bienvenue à bord!
Here in São Paulo we had (and still have) trains with a do-re-mi inverter and jeumont Schneider DC chopper, in the case of the do-re-mi inverter we have the CPTM series 3000, and in the case of the jeumont Schneider chopper we had the series 5500 "eletrocarro" from CPTM, the frota C of the São Paulo subway (current frota K of the São Paulo subway) and series 5000/5400 from CPTM "fepasao" the first and at the same time the last Jeumont Schneider chopper in São Paulo and Brazil
@@GabrielVictor-te2sk And actually the only system to use those choppers that wasn't a rubber tired system, and the only other one remaining, since Mexico City replaced the Jeumont equipment in their MP-82 cars...
@@wilfstor3078 remembering that the eletrocarro was retired in 2012, however it had a modernized version called 5550 that operated until 2016, the 5550 as well as the mp-82 of the mexico city metro had its Jeumont Schneider chopper replaced by electronic management equipment, however its original traction engines were maintained (although revised), during the renovation it had its original front (here in São Paulo we call it the front of the trains mask) of 3 stainless steel windshields replaced by a fiberglass front with 2 windshields, the frota c between 2009 and 2014 was modernized, becoming the frota k, just as the 5550 had its original front replaced by one with a modern appearance, was equipped with air conditioning, and had its original jeumont Schneider choppers exchanged for a very silent vvvf and the original DC motors exchanged for AC motors although the rotor of the traction motors remain the same (the original mechanics were maintained), as the traction sound of the frota k is similar to that of its original form, whereas the 5400 is very difficult to show, as only one operates and most were immobilized
The reason for the variable switching frequency is that there is a MINIMUM ON TIME.
Another example would be the czechoslovakian class 363 locomotives that had three distinctive switching frequencies 33,1/3Hz 100 and 300Hz. Due to the fact that the thyristors needed forced commutation trough a commutation reactor and cappacitor, they were limited to a minimum turn on time in which they will get a consistent firing of the main thyristor (After firing would stay conductive until the commutation tyhristor takes over to shut the main thyristor)
This had one problem. With a fixed Ton you would have a minimum Duty cycle far too large for reasonable starting of the train. Basically the loco would instatnly start to slip and rip off the connection between the cars.. What they they did is that they decreased the switching frequency only for small powers so after reaching a certain time threshold the inverter switched to a different frequency allowind for a much better distributed current draw. After all you need a smaller inductor for a 300Hz pulsed DC to smooth out, than if you had 33Hz pulsed DC
The class 363 is an early 1980s design locomotive, incorporating PWM regulation of DC traction motors. The switching was done with thyristors (the OG ones not these newfangled funny GTOs :D ) so they needed to get creative.
Minimum reliable Ton (that would guarantee main thyristor conduction) was 0.3ms. This on time at 300Hz would result in a 9% duty cycle right from the starts...that wont do!
So what they have done is go trough 3 frequencies. 33 1/3, 100 and 300
Duty cycle as follows
33 1/3 from 0.9% to 3%
100Hz from 3% to 9%
300Hz from 9% to 90%
This allowed for a reasonable efficient controlling of voltage, and during the riding stage the use of a 300Hz frequency allowed for a smaller filter inductance to smoothen the current out and consequenty so that the torque is constant instead of being pulsed at 33Hz (funnily the whole thing rattles at this frequency during a run up)
incase of the N1000 the motors are asynchronous AC. They modulate the low frequency sinewave into the pulse width. Change of frequency changes the RPM. But asynchronous motors have a voltage over frequency curve. The higher the frequency the higher the voltage, demanding a larger PWM swing. So for full on 50Hz lets say, you need full modulation from 0% to 100% dutycycle. But for 5Hz you need 0% to 10% and this might prove problematic due to the minimum on time of the thyristors. So the simplest solution is to change the frequency of the modulated pulses. Any time you can afford to make the frequency higher you should do it as it increases smoothness of operation and homogenises current flow into the motor windings.
I hope this rather technical essay helped clear things why they make this sound..
Why do trains then go to pattern mode at higher speeds? is it for harmonics or switching/ minimum on time. Also why bother keeping the PWM carrier fq low at startup and then raising it with modern VFD inverters?
That was the answer I was looking for to my question of why is the stepped sound made when PWM is being used
legend.
@@wezdog1 this is an asynchronous thyristor inverter speciffic thing. With a changing modulation freqiency you hit a point when the carrier frequency (the switching frequency) and the mpdulated frequency are gping to multiples of each other. 1/10 1/8th 1/4th 1/2 1/1 2 4 8 10... it cannot be an even multiple. This is due to phase crossing points. It might cause a quirky behaviour where some DC could be let trough and that would cause DC magnetisation of the motor core or utterly abolish the thyristors..
Wow, thanks for the explanation 😮
Our subway trains still use 400 Hz for something. I love this sound especially when two sources form a binaural wave. It reminds me old good days...
haha the green ones with white lines. I think the English translation of the way they are called is "number trains" idk. 81-717/714 type. I have not heard the new ones make the same sound. At least in Moscow.
In Central EU there are trains that still uses theese. Freight trains, like Siemens Taurus, ect. When an OBB Taurus is departing from our local station, I allways stop, and listen to it, it is so god damn good...
As far as I know, they pick the inverter frequencies to change at low speed to avoid resonance in the circuits - they could pick any ascending frequencies, but why not make it sound nice! I respect the engineers that picked it. It's a really nice touch.
for the 100th anniversary of the ÖBB (Österreichischhe Bundesbahn - Austrias train company), they controlled the inverters of some trains, so that the trains played Happy Birthday
need to see that footage, any link or maybe some seach keywords?
@@WilTK4 i think, I saw it on Twitter from the account of an train driver.
The first AC train motor inverter ever was Helsinki metro M100 stock's Strömberg equipment from 1977. Plenty of YT videos available. The frequency divisors are a series of small primes. The equipment was also used in the Finnish Dr16 engine and the prototype of the gigantic VL86F Soviet engine that unfortunately fell with the Soviet Union.
1:42 ElectroBOOM from Japan be like lmao
😅😅😅
When braking, energy is returned to the inverter capacitor. Which can explode. Therefore, for safety, this energy must be dissipated using a brake chopper or returned to the electrical network.
4:55 I think that engineer just needed to deal with switching frequency in audible spectrum..so they decided to tune it, instead of let it annoyingly whine...
My friend, the SIEMENS Eurosprint "TAURUS" locomotives use a doremifa inverter and are still in operation in Germany and Austria.
Yup, seen them in Hungary too.
And Norway.
@@AttilaTheDevimádom😅
Siemens still do this,in their IC trains
you can somewhat even hear it in things like the siemens charger locomotives that via rail uses. Its very subtle though
@@SkysTrains really?? i've never heard it. any good videos of it?
@@CTSLRailfan I've heard it while standing right beside a locomotive but I never quite caught the sound or heard it in a video. It's very subtle and hard to hear over the engine.
this reminds me of jubilee line, I've always loved the way it sounded, sounds like a car changing gears..
if I was designing an electric sports car i'd definately consider integrating a similar system instead of those fake speaker pumped noises we see nowadays
That, and the Class 465/2 465/9, and 466 used on SouthEastern, have a slightly later technology using continuous variable frequency rather than stepped variable frequency.
Every possible permutation of singing train is used here in the UK, it's great! 😂
I even remember the old resistor bank DC controllers with their clickity clack.
Lots of people think EVs have no soul. This can definitely bring some soul back to the drivetrain!
can you imagine what a traffic jam would sound like? It would be a cacophonic nightmare.
exactly what I was thinking..
The soul of the car is the sound of combustion, the vibrations and the control you have. EV's have no soul, no matter how much they try those fake sounds.
Rimac might have a decent sound that gives it a soul, but will never replace the sound of combustion nor is it as much as exciting
As a developer for multi megawatt inverters that have wide range of different sounds between 1...10 kHz, iam always disapointed from the sound of my EV.
@@AlexLTDLX A little good intention driven dystopia gives live some fun.
Modern inverter are better in making real sine waves therefore they make less noise and are more efficient. A low power equivalent are stepper motor drivers. Some people played songs on printer or even floppy drives with that.
Modern brushless motor controllers very much still play audible sounds on startup or failure.
@@AttilaAsztalosYes, however those are intentional, and done without moving the motor shaft. During actual operation, the brushless motors don't actually make much sound.
I've seen the floppy music videos, they're cool!
The reason the Keikyu N1000 series has those singing motors is that the VFD was manufactured by Siemens. Siemens was known for making "singing" GTO VFDs. Their EuroSprinter (aka Taurus, ÖBB Class 1016/1116) locomotive is a great example of that, and it's one of the most iconic and loved modern locomotives just for that reason alone.
13:04 This sounds like a EuroSprinter locomotive starting while hauling a heavy freight train. I think they used the same inverter, but the motors probably had a different gear ratio in the EuroSprinter, because it is a high speed locomotive (certified up to 230 km/h).
actually, the reason for the switching frequency change even though it is an induction motor is to control the losses during startup and very high slip conditions
12:04 if electric cars sound like it has a gear shifter using this motor, it would be a massive hit😂
When I heard the name of the inverter, I first thought it was a Japanese word, but seeing it spelled out in the description made me remember the musical scale, which made the sound make more sense! Gotta love Japanese humor!
I hear 1000 and I think Shinkansen. I miss that train design. Clearly I ignore the fact you say "N" 1000. You brought back a deep memory I forgot I even had. When I was younger, my father would frequently take me to Japan to visit his side of the family. Hometown on Kyushu Island. But you don't go to Japan without touring Tokyo, and re-visiting the places he moved to when he moved to Toyko area - Yokohama, and Shinagawa. Hearing that sound, that I have not heard for over so _so_ long, brought back a lot of good memories. Thank you. And very interesting video!
I've been so fascinated with singing trains since I was a child. Thank you TH-cam for recommending this to me!
We have a train in the UK known as the Class 323 that makes a distinct sound due to originally having GTO Thyristors (made by Dutch manufacturer Holec). Instead of music, they sound more like a racing car going through the gears though. More recently they were upgraded with IGBTs, but these were programmed to produce the same frequencies (since that meant they didn't need to be retested for electrical interference) which means they make the same sounds.
Class 465 BREL used to have these too. Probably an abb gto's
One of the reasons it does notes is that the fundamental inverter frequency and its harmonics have jump in order to avoid getting into the frequency bands of the audio frequency track circuits.
I wasn’t expecting you to MAKE the inverter controller circuit board. Nice touch.
This is probably the most geeky video that I watched in a while and I love it!
It took a moment to realize that the name of the inverter comes from the “do re me fa so la ti do” tool for teaching music.
I really thought it was a Japanese word lmao
@ Same.
The name of inverter is VVVF
Finally someone that understands why trains make that sound that actually explains it in plain English. I watched your videos in awe in the past but couldn't understand a word as you spoke Japanese. Now the time has come! 😎
You can hear similar sound in Busan Metro Green Line (2nd line) in Korea, but it just ramps up and down like a sawtooth wave.
Siemens locos in Europe also have the same melodic inverters. Many thanks for both videos, they're most interesting.
At eighties my city had first Škoda 14Tr trolleybuses who made this kind of sound. It was something out of world amazing :)
Montreal Metro MR73 -- have Inverter sound too (3 notes). The sound have become so popular that it is use (Replicated) to indicate that the door will close... Then, when the train start (The inverter this time). The most recent Metro units don't make noise anymore.
Here in São Paulo, Brazil, we had a train that problably used this motor because the sound is very similar. I always loved this sound!
Whats is the class? Is it a CPTM Or Sao Paulo Metro
CPTM TUE series 3000 GTO based inverters @@biancadarosa9053
@@biancadarosa9053CPTM series 3000 I believe
@@Spreffy ooooh okay
1:55 "if you touched it you're dead" 🗿🙏
I have watched your original video before, but I'm watching it here again. Nice video, and nice translation.
I guess the DoReMiFa frequencies were chosen simply because anything else would sound weird or wrong or unexpected. With a well defined set of frequencies, the public would always recognize the sound (safety and branding) and not worry about it. And the proper frequency of the inverters can be very easily checked by listening and so a defect may be quickly noticed by accustomed train personnel even without conscious listening.
This is nuts! Reminds me so much how our RC planes works!
Yep very similar except with permanent magnet motors rather than induction motors
I didn't know this was a thing in RC planes.
Thanks alot for the video with the explanation 🙏
I remember this sound from the time, when I traveled first time to Tokyo.
And I also recognized it at Vienna.
But I had no idea, that they did it on purpose.
Maybe I can add a soundcube in my brick built Monorail with this sound 🤗
Greetings from Switzerland
Buttermaker
Since Poland is like two decades behind on train tech we go them like few years ago. I like how they sound.
Which class/model is it exactly?
@@z00h I remember hearing them on some of the refurbished EN57 that ride near me.
@@erwinkonopka7071 and that makes Poland "like two decades behind on train tech" in what way, fella? ÖBB still run singing Taurus locos in their diagrams.
Thanks for the video. I did had an privilige to travel with that singing train when I visited in Japan. Please also check Helsinki metro M100 series. It is the worlds first VVVF train designed and came into to service in late 70's. It is still in use! I went to school with it in the 80's and later to work with it.
Martti Harmoinen at Strömberg invented VVVF.
This video is how I discovered your japanese channel. Seeing it translated feels good, as I understand it better. Thanks a lot
Literally yesterday asked myself that question. Today appears suddenly this vid on my YT feed.... Crazy! Amazing video, Thanks for sharing your knowledge
My favorite use of the system is the variable voltage variable frequency gate turn off equipped Siemens EuroSprinters, most particularly the so called "Taurus" models (ES64U2). Such locomotives are popular for both passenger and freight applications. My favorite rolling stock period.
What a cool demonstration!! Thank you!!
I've heard this trains in Switzerland many times. The trains that travel between Zürich HB and Viena Hbf
When I first heard a video of that train I was like this is the coolest thing Ive seen (or should I say heard)...safe to say whoever the engineers were, they were also musicians!
Also side note you can kinda tell the technology is older cause there are so many "steps" in the acceleration/deceleration even after the singing part...one of the more modern versions of this idea, the NYC R160B with Siemens IGBT has smoother sounding acceleration (but it also has only a single 400Hz "note" in the low speed area so I totally get it if you don't think it's as cool)
Im not sure if this is just me but the acceleration on the R160B makes it sound a lot faster than it is
The Sawtooh PWM cycle is meant to limit inrush current and shake off friction. It just so happens that is makes the do ray me sound. it was the best way to utilize the technology they had at the time.
That train is legit wonderful & relaxin', tbqh :D
The ÖBB Taurus has a similar system for their electric system. A student college of mine once told me: "I was always wondering who plays such bad violin sounds all the time, until I realized it's the train" :D
That was brilliant thank you , I love that sound , very cool
Didn't expect to see soldering stencils here. That's hardcore. And I never thought about using a griddle!
I was always curious about the sounds that TAURUS locomotives make, now I understand.
Thanks for the time dedicated to the experiment.
I would say the steps are to keep the power input constant during starting, as the power needs of the motor change because of the need for increased slip during the initial power application, and the steps are there to reduce the CPU need for a smooth sweep, as the original designs used lower speed processors, so offloading most of the power control into discrete power steps was needed, so as to not cause excess slip in the motor and thus poor accelleration, and too fast a ramp would result in a motor stalling. thus the constant steps, so that a driver could keep a constant pull away and not run the risk of a stall, which would mean a stop and a slower ramp up again, and a possibility of the motor generating an overcurrent or tacho feedback error. remember this was originally running likely on aZ80 or similar processor, with large parts being done by other processors as well, and the designers had both limited memory and limited performance.
400Hz was running the GTO devices at the high end of the range, as they, for power devices at the time, needed 2 or more same size power switches for each of the 6 legs of the drive, and GTO devices need you to have a very beefy current source and sink, as you need to turn it on fast, so high current at a relatively low voltage of around 5V on the gate, and turn off you need a current about what the device is conducting, and around -10V, to pull the gate off hard and fast enough to switch off. At least this was better than earlier thyristors, where turn off was done using LCR circuits, and a second equally rated thyristor to pull the anode negative for long enough that the first one would be able to turn off, and then the second one, due to the high power resistor providing it with power, would stay on till the first fired again to turn it off. High static current, high power loss, the GTO made this power use so much lower, at the expense of needing 4 isolated relatively high power supplies, 3 for the upper bridge, and the lower one having a common cathode connection. Instead of 500W of power dissipation now down to under 100W at idle. Add this up per axle and the power use becomes considerable, plus higher frequency, and the ability to do regenerative braking with much less processing power, and you can see why they, and now the IGBT, won out.
Great video! Yeah, I bought one of those industrial fans one time to use for filtering solder fumes at my desk and it is VERY loud lol! It moves a lot of air though
You just haven't ridden in the Ема-502 ...
In Japan, trains run for 15-20 years ... meanwhile in Kiev Kharkov and St. Petersburg trains run for 50-60 years xD
Waiting to make a rheostat controller for a DC colector motor ))
so much fun, I could play all day long!
Perfect job! Thank you!
👏👏👏👏👏👏👏👏🔥🔥🔥🔥🔥🔥🔥🔥🔥👌👍Bravo! Now perhaps the train simulation folks will take notes and get these natural sounds. Tremendous work you did here!
In the Mexico City Metro, the entire fleet of line 8 is made up of Bombardier NC82 pneumatic trains with 9 cars that also have a characteristic sound when accelerating and braking, considering that they are powered with 750 volt direct current and also uses DC motors.
Glad to have been recommended this video.
Thank you for the video! Greetings from 1520 rail gauge in Russia
Here in Brazil (São Paulo city) CPTM trains make this sound! Thanks for the explanation!
We had two indoor 100 HP HVAC fans that we installed VFD'S on back in early 1980's and depending on the speed you could hear the odd sound produced by drives several hundred feet away. Place that I retired from had over 500 VFD'S and being they were on drives that used IGBT'S with up to 5,000 Hertz switching frequency only receivers rattling sound on a few of them.
Its a very neat and informational video. Very well done
That is very silly and I love it. I wish the T had trains like that when I was taking the trains in and out of Boston.
Here in Portugal we have fairly recent trains that make a similar noise, IF i'm not mistaken they are made by Siemens-Bombardier however is well muffled and is hard to tell if it the same type of frequencies.
While most people would consider it noise compared to this, the electric motors in my local metro have a very distinct sound, even after they changed the old trains with the new ones... It just gets into your brain.
I would have loved it if you showed the code to make the various sounds...
They sound nice!!
Thats a frickin gearbox for electric motors. Dope af 14:44
Japan is Master of all things Trains, from small scale train sets to full scale national transportation.
Not gonna lie it took me 3 minutes to realize the lips don't match the words. 10/10 translation
Funfact
We got two trains in Germany that Sounds like N1000 Keikyu
BR182(ES64U2) and 424/425/426 EMU
If You combine those sounds you get the singing Keikyu train
you can often hear inverter noise from electric cars these days, and most sound like they’re using variable-frequency control modes, which don’t produce pure tones. presumably carrier frequency modulation for EMI reduction - varying the PWM frequency spreads the harmonics out and can significantly reduce high frequency peaks that could otherwise cause interference
"Which instrument do you play?
I play train motor"
I've looked a bit into this and I have a theory for why this sound is: it's not that GTO Thyristors are limited to a few hundred Hz.
Basically, when you have an AC motor, be it synchronous or asynchronous, the speed where you have maximum torque is directly correlated to the line frequency of the AC sine wave.
The inverters used in trains control the motor with a scheme called V/Hz, where they gradually apply sine wave voltages of ascending frequency, starting very low and gradually increasing the frequency as the motor speeds up.
They raise the frequency in discrete steps, this is what makes the "gear shift" sound, which in this case was deliberately made to match a musical scale.
There are other more sofisticated control schemes, such as FOC, which calculate in real time the exact optimal current for every coil of the motor in relation to its rotation, such method is used in electric cars and is much more silent.
What does change between GTOs and IGBTs are the harmonics in the sound: the inverter can't make sine waves directly, it can only ever turn the power electronic devices fully on or fully off, making square waves.
By modulating a high frequency square wave in a certain way and filtering it through a capacitor, you can make a sine wave. GTOs can switch at about 1-2kHz, while IGBTs reach tens of kHz, meaning the GTOs will superimpose additional audible harmonics on the final waveform
Here I was thinking there was some kind of transmission making that noise. How wrong I was. Fascinating!
This was really awesome, thank you!
11:58 For running the finished product.
i got a chance to hear that sound ,now i know why thank you
The reason for this sound should be something about magnetic field and efficiency at extremely low RPM. Nissan Leaf has stall protection, that if motor is hardly turning it will not use regular high frequency swithcing and will downgrade for lower one, more heard, but more efficient and less heat output at low rpm.
Nice! I live in Austria and I'm used to the sound of the "Taurus" locomotives which is similar, though if I recall correctly, the musically sounding sequence is shorter than in the trains you showed.
The R142 and (some) R160 cars on the New York City Subway system use an Alstom ONIX 800 IGBT system, and play the first three notes of "Somewhere" from the musical "West Side Story" as the train accelerates.
Thx and kudos for this you put a soul into an electric device 😊
Hi Denki, this is a great video. Thank you. Did you try sending a mail to any of the engineers back in the day to understand the real reason behind it. It could be very interesting to know definitively than seeing so many nice speculations in the comments.
The N1000s with the singing inverters are still technically in service however they were retrofitted with less cool more modern inverters.
As an engineer and music lover, I assure you that the frequencies were not chosen coincidentally 😂
Here in the east of Germany we have now electric trains which are making exactly this sound if they start driving. For us this devices are totally new and Japan have stop working with this, because they have newer motors. Impressive.
A note, I remember a video featuring a crane with some sort of MODERATELY high pitched music music synthesizer serving the purpose of a hazard beeper
At first thought, it sounds stupid, and/or janky, but if you do your research
It's actually genius. Music is a lot harder to tune out than a repetitive beep
The Siemens Taurus, used widely in europe, and Keikyu’s “singing trains” actually make essentially the same noise.
I hear examples of this on Thameslink UK trains, on Amsterdam trams and, most recently, on Prague trams.
Interestingly, I haven't yet heard trolley buses making these sounds.
Modern IGBT-Inverters are fully computerised and can play any monotonic tune. The ÖBB Taurus sometimes even plays the austrian national anthem and the german ICE 3 can play the german national anthem in service mode. The only reason why there aren't more trains playing sounds is because adding fun features is not "formal" enough.
Therapist: Asian Dave from EEVEblog doesn't exist he can't hurt you
Asian Dave: 1:55
Place the fan further from the fins of the heat sink, by adding a length of pipe, to avoid the shearing effect of the blades. This should ,,cure" the noise from the fan.
Here in brazil we have the cptm 3000 series maded by siemens, the singing train, pretty similar to japanese singing trains
I also like interesting Trains making electric sounds 😉
Thank you so much for the knowledge, Thailand FC 🙏