[Inductor-Recorded Traction Motor Sound / モハラジオ録音] SEPTA Silverliner V [Mitsubishi IGBT-VVVF]

[@nickloh912]

Thank you for all your videos (and especially for the detailed explanations that accompany each one). I'm glad I'm not the only one who finds these noises interesting. Philadelphia is my home town and I spent a lot of time riding these to and from college. I always wondered why they did not have the very obvious ramping noises like the NYC M7s despite also having Mitsubishi propulsion.

[@ebaraexpress7260]

Thanks for watching! Yes generally 3-level IGBTs are quieter than 2-level ones. Also I have posted other SEPTA cars, so hope you will also enjoy that!

[@Jones5121]

0:15 sounds sort of like the direct self control that some german locomotives use (class 101 and 145 come to mind)

[@KuMoHaVVVF]

very interesting to see the unipolar/dipolar methods of control outside of japan, never knew of any overseas example

[@viciadoemdorflex]

Could youmake a video with the CPTM 2500 and 9500 series? Thanks 🙏🏻🙇🏻‍♂️❤

[@TUbe-bv4fy]

He doesn’t accept any requests

[@goofyahhnerdyy]

Can you do WMATA 7000 series next?

[@ebaraexpress7260]

@@goofyahhnerdyy Apologies, I don't take any requests. However, that car's sound has already been posted here by my fellow: kzbin.info/www/bejne/nnncgWBvfp2MadUsi=aHtLq1S19fHkvG8u

[@goofyahhnerdyy]

@@ebaraexpress7260 Oh i forgot about that video, oops.

[@winstonpx]

Why is bipolar modulation used if unipolar modulation is generally superior in performance/efficiency?

[@ebaraexpress7260]

patentimages.storage.googleapis.com/16/8c/08/82d1ed6e25c222/JP2006197798A.pdf P. 6 Lines 12-17 "However, the previously known unipolar modulation method cannot achieve a voltage pulse smaller than the minimum output pulse width determined by the minimum on-time of the switching device in the region where the inverter frequency is low and minute output voltage control is required (near the starting point of the VVVF control region), As shown by the dashed line in Figure 2, a voltage larger than the command will be output." In order to resolve this problem, dipolar modulation has been applied for 3-level inverters.

[@winstonpx]

@@ebaraexpress7260 Oh I see, so when the train is just starting to move dipolar is used because a low voltage cannot be achieved with unipolar, then it switches to unipolar after more voltage is needed due to efficiency 👍