[Inductor-Recorded Traction Motor Sound モハラジオ録音] E4 Series Shinkansen

#モハラジオ #TractionMotorPWMSound #E4Series

00:00 Title & Introduction
00:05 File 1: Acceleration
03:18 File 2: Braking

Car Type:
JR East E4 Series Shinkansen

VVVF:
Mitsubishi 3-level IGBT-VVVF

Sound Characteristics:
Pattern:
Asynchronous (Dipolar Modulation → Unipolar Modulation) → Multi-Pulse Mode (2 Steps) → 1P
Asynchronous Mode Carrier Frequency:
220 Hz Constant (Dipolar Modulation)
Approx. 320 - 360 Hz (Variable) → (Continuous Transition) → 685Hz Constant (Unipolar Modulation)
*RCFM is applied throughout the asyncronous modulation. Also for the dipolar modulation, the most emphasized component is around twice the carrier frequency.

As is typical of Mitsubishi 3-level IGBTs from the late 1990s, for asynchronous modulation, RCFM is used, and a continuously changing center carrier frequency is adopted. However, it is noteworthy that there is an intermittent change in the transition from dipolar modulation to unipolar modulation. Additionally, after passing through two types of synchronous multi-pulse modes, it reaches 1P, but the change in modulation index becomes larger after switching to 1P, which is a unique feature of this vehicle.
This sound was recorded on the floor near the wall separating the equipment room in the passageway at the end of the car, as shown in the last photo.

The AC traction PWM sound shown in this video is recorded by a sensor. This sensor is made by myself just using a 100 mH 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.
This sound is recorded in August 2021.
Sorry, I am NOT taking requests for recordings.

Posted by Ebara Express
X (Available in Japanese; translate please!):
https://x.com/VVVF_tokyu2000
Website "VVVF Database" (Available in Japanese; translate please!):
https://vvvfdb.stars.ne.jp
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