[Inductor-Recorded Traction Motor Sound モハラジオ録音] MBTA Type 8 [ADtranz/Bombardier IGBT-VVVF]

#モハラジオ #TractionMotorPWMSound #MBTA Car Type: MBTA Type 8 VVVF: ADtranz/Bombardier 2-Level IGBT-VVVF PWM Pattern: Asynchronous (250 Hz → 500 Hz Constant) → Advanced PWM (2 Steps) → 3P → Wide 3P → 1P This is the type of sound often heard in traction systems for the U.S. market, manufactured between the transition from ADtranz to Bombardier. The similar type of VVVF is also used in some NYC Subway cars. See video below:    • [Inductor-Recorded Traction Motor Sound モハ...   During asynchronous modulation, the carrier frequency initially rises from 250 Hz to reach 500 Hz and then remains constant. The rate of increase of the carrier frequency is not constant, but gradually increases in this rising part. As for the synchronous modulation, after two advanced pulse modes, it changes in order of 3-pulse mode, wide 3-pulse mode, 1 pulse mode. The advanced pulse modes are numbered (1) and (2) for distinction, but (1) is processed in such a way that it is smoothly connected to the asynchronous modulation, and this part has a unique sound. The identification of pulse modes by these numbers will be done in this video and the above NYC Subway video, and will be valid only in these two videos. In this video, the section of wide 3-pulse mode which I called "Cruising", does not actually maintain the speed, but decelerates slightly. However, when the train is totally coasting, the sound is cut off and it seems that the motor is not energized. Did the driver put the lever slightly to the brake side during this section? I'm curious about the method of operation. The AC traction PWM sound shown in this video is recorded by a sensor which is placed on the floor of a train car near its traction motor. This sensor is made by myself just using a 100 mH inductor. 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 March 2019. 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 Please click here to subscribe:    / @ebaraexpress7260