In Finland we have the first metro trains to use AC (fully in use, not as just a test) motors in the world. They're still in use and sound awesome, since 1982. They generate AC from 750V DC third rail power. Might get an impression that I'd be talking about DC PWM, but no they actually use induction motors.
Knuckles the Echidna Yep, I have filmed them several times. The 323 works in the same way with AC PWM. It accelerates quickly and goes through loads of switching patterns. The Midland metro has the same transistor control as Manchester tram 2000 (now replaced). These were built later on and have transistors which switch much faster, but they still use the old method of switching, which is a great example of old style switching at higher frequencys. Also they were some of the last trains/trams to use the old method of switching.
***** I wonder what the transistors look like? Perhaps they are like a normal transistor but 1 foot tall or maybe lots and lots of tiny transistors working together attached to a giant heatsink? I want one to attach to the wall above my bed next to my Ecodisc hoisting machine (that I also wish I had) as a souvenir :D
Knuckles the Echidna When putting semiconductors (such as transistors) in parallel there is the problem of making sure that the current is evenly distributed between them. Due to manufacturing tolerances, no two transistors will have the exact same resistance. Even though the differences in resistance could be tiny, it will mean that one transistor will heat up slightly faster which will reduce its resistance making the problem exponential. There are some pictures showing large current transistors in this Wikipedia article... en.wikipedia.org/wiki/Insulated-gate_bipolar_transistor
The Eurostar train is the only train I know of the have an audible VF drive on the fan motors aswell as the the train's traction motors. On some models of train the diode bridge can be heard in the carriage with the pantograph. It is a 100 hz hum that gets louder when more power is used. The more acceleration the train has the louder it is. But it does not change pitch. It always stays at 100hz. Can be heard on the 345 crossrail train.
![[Inductor-Recorded Traction Motor Sound モハラジオ録音] DART SLRV [AEG GTO-VVVF]](/img/1.gif)
A video describing a neat set of sounds with a thorough explanation as to why they occur? Excellent! That was very interesting to read.
I read the Description and it was superb. Thanks and it was interesting
In Finland we have the first metro trains to use AC (fully in use, not as just a test) motors in the world. They're still in use and sound awesome, since 1982. They generate AC from 750V DC third rail power. Might get an impression that I'd be talking about DC PWM, but no they actually use induction motors.
It's a shame that Eurostar tickets are so expensive, I want to ride on one of these again
I love these trains:)
AWESOME
Ever heard the class 323 that train makes an amazing sound! Also Midland Metro makes a nice noise too.
Knuckles the Echidna Yep, I have filmed them several times. The 323 works in the same way with AC PWM. It accelerates quickly and goes through loads of switching patterns. The Midland metro has the same transistor control as Manchester tram 2000 (now replaced). These were built later on and have transistors which switch much faster, but they still use the old method of switching, which is a great example of old style switching at higher frequencys. Also they were some of the last trains/trams to use the old method of switching.
***** I wonder what the transistors look like? Perhaps they are like a normal transistor but 1 foot tall or maybe lots and lots of tiny transistors working together attached to a giant heatsink? I want one to attach to the wall above my bed next to my Ecodisc hoisting machine (that I also wish I had) as a souvenir :D
Knuckles the Echidna When putting semiconductors (such as transistors) in parallel there is the problem of making sure that the current is evenly distributed between them. Due to manufacturing tolerances, no two transistors will have the exact same resistance. Even though the differences in resistance could be tiny, it will mean that one transistor will heat up slightly faster which will reduce its resistance making the problem exponential.
There are some pictures showing large current transistors in this Wikipedia article...
en.wikipedia.org/wiki/Insulated-gate_bipolar_transistor
Wish they still used the pattern changing pulse VF.
I love the noise! :>)
Can someone explain which is the sound of the fan motors, is the more distant sound ? And can someone explain which is the sound of thr diode bridge ?
The Eurostar train is the only train I know of the have an audible VF drive on the fan motors aswell as the the train's traction motors.
On some models of train the diode bridge can be heard in the carriage with the pantograph. It is a 100 hz hum that gets louder when more power is used. The more acceleration the train has the louder it is. But it does not change pitch. It always stays at 100hz. Can be heard on the 345 crossrail train.
It sounds a bit like a networker at low speeds
Where did you get the information on 373 ?
Talking about a 90s processor do they used something like an Intel pentium one?
CineRaphael Commodore 64 🙃
DFN oh yea this one from the 80s.
class 373 used to be on dc
Like Taiwan Railways Administration UCW E1000 Electric locomotive