[Inductor-Recorded Traction Motor Sound モハラジオ録音] 700-7000 Series Shinkansen

#モハラジオ #TractionMotorPWMSound #700Series
00:00 Title & Introduction
00:05 File 1-1: Type 1 Acceleration
02:56 File 1-2: Type 1 Braking
05:22 File 2-1: Type 2 Acceleration
09:11 File 2-2: Type 2 Braking
11:35 Manufacturer Presumption
Car Type: JR West 700-7000 Series Shinkansen
VVVF: Mitsubishi/Toshiba? 3-level IGBT-VVVF
Pattern (Type 1):
Asynchronous (Dipolar Modulation → Unipolar Modulation) → Multi-Pulse Mode → 1P
Asynchronous Mode Carrier Frequency:
500Hz (Dipolar Modulation) → 1000Hz → (Continuous Transition) → 1200Hz (Unipolar Modulation)
For the dipolar modulation, the most emphasized component is around twice the carrier frequency.
Pattern (Type 2):
Asynchronous (Dipolar Modulation → Unipolar Modulation) → Multi-Pulse Mode → 1P
Asynchronous Mode Carrier Frequency:
500Hz (Dipolar Modulation) → 1000Hz (Unipolar Modulation)
For the dipolar modulation, the most emphasized component is around four times the carrier frequency.
Sound Characteristics:
Please refer to the "Manufacturer Presumption" section of the video.
Others:
The following website summarizes the distribution of the two types of sounds:
iamreck.g2.xrea...
(Red = Type 1, Green = Type 2)
In addition, although it is from the C sets which have already been retired (the traction system is different from the B/E sets), there is a description of the pulse mode of Fuji Electric VVVF in the PDF below, as "Asynchronous → 15P → 9P → 3P → 1P".
www.fujielectr...
This may be the reason why the sound of C sets' cars that are thought to be equipped with this Fuji Electric's VVVF is different from the Type 2 in this video, especially for the time when shifting to synchronous modulation during acceleration.
The sound sources for the other cars in this video can be found below.
・Meitetsu 3100 Series (Toshiba Traction)
vvvfdatabase.st...
・JR East E2-1000 Series
• [Inductor-Recorded Tra...
・Sapporo Municipal Subway 5000 Series (Mitsubishi Traction)
vvvfdatabase.st...
・JR Kyushu 800 Series Shinkansen
• [Inductor-Recorded Tra...
・Additional data
① 700-7000 series (Type 1) with frequent chattering during braking
② EH200 series departure recorded from outside the car (on the platform)
x.com/VVVF_tok...
* The AC traction PWM sound shown in this video is recorded by a sensor. This sensor is made by myself just using a 100mH inductor.
* Regarding the files used, the extra noise components has been reduced from the ones saved immediately after recording.
* Due to the resolution of the spectrogram software, the frequency displayed in this video may include some error. Thank you for your understanding.
* These sounds are recorded in 2022 - 2023.
* Sorry, I am NOT taking requests for recordings.
Posted by Ebara Express
Twitter (Available in Japanese; translate please!)
/ vvvf_tokyu2000
Website "VVVF Database" (Available in Japanese; translate please!)
vvvfdatabase.st...
Please click here to subscribe!
/ @ebaraexpress7260
BGM: MusMus

[@ebaraexpress7260]

Apologies, regarding the Type 2's braking data, the correct switching timing for 1P → multi-pulse is at 9:46.
Type 2の減速時における1P→同期多パルスの切替タイミングは正しくは9:46になります、ご承知おきください。

[@zeraneko]

やっぱ最初のは急上昇タイプだったんですね。同期モードが聞こえにくいから1Pオンリーかと思いきや…。
Type2っぽいのはC編成でよく見かけましたね〜

[@Kane615]

Fantastic video as always! This is perhaps going to sound silly but I've been having issues recording certain stock while accelerating due to transient noises like those that can be heard starting around 0:18 and I was curious if you had any info or theories as to what is causing those noises?

[@ebaraexpress7260]

Thank you! That kind of noise might be caused by contact between wheels and a rail, or if that train is running in a third rail section, then that should be caused by the rubbing between the contact shoe and the conductor rail.

[@CR400AF-B]

The waveform of the dipolar part in type 1 looks more like 250Hz and 50% dipolar rate (quadruple).

[@ebaraexpress7260]

Maybe that is because you see lines around 2700Hz and 3300 Hz, but they are from input AC side (there was a bold line around 3000 Hz so I reduced by a notch filter, however these edge components are still remaining here) and not from the inverter.
Also, if that kind of modulation you mentioned is applied, there should be components for 750 Hz and 1250 Hz, but not visible here. Moreover, Mitsubishi hadn't used that kind of modulation until late 2000s. Therefore, I think this is 500 Hz with 70 % dipolar rate.

[@CR400AF-B]

@@ebaraexpress7260 The pulses in the waveform (not the spectrum) seems to be equally spaced, but the pulses in the twice frequency bipolar mode occur in pairs, so it is suspected to be a 250Hz quadruple dipolar mode.

[@ebaraexpress7260]

⁠@@CR400AF-B When determining a PWM mode, we rely more on the spectrum than on the waveform.
Since we cannot remove noise components from the displayed waveform results, it is difficult to judge the mode. Also, there are some cases that inductor recorded data is more like a phase current than line-to-line voltage, which causes confusion for judging the mode; on the other hand by spectrum we can judge from both phase current and line-to-line voltage, since they are showing similar results: yuppi5.hateblo.jp/entry/pwm2
So, for this case, since I give more weight to the fact that there is no 750 Hz and 1250 Hz spectrum shown, let me conclude this as 500 Hz.
Anyway I'm so interested in the way you guessed.

[@CR400AF-B]

@@ebaraexpress7260 Your analysis is reasonable. From the spectrum, it looks more like the E2 series, and 500Hz is also a reasonable switching frequency for 3300V IGBT devices during motor start-up. Indeed, when doing moharadio on many China high-speed trains, the superposition of multiphase currents and noise makes it difficult for me to see the waveform clearly.

[@taroimo_vvvf]

😌

[@minecraft_javjavatonkoonca8109]

😮