Відео

@@NF_2216 Above the inspection lid on the floor.

You mean the Bx6 not the Bx12

@@goofyahhnerdyy Apologies, I don't take any requests. However, that car's sound has already been posted here by my fellow: ua-cam.com/video/hHyP-9I8Y3s/v-deo.htmlsi=aHtLq1S19fHkvG8u

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

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!

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.

@@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 👍

He doesn’t accept any requests

@@w_avor I'm just using a 100mH inductor, and then do the craft for attaching lines to earphone jack so that can be connected to the IC recorder.

It has DC motors, probably not applicable

@@QuarioQuario54321 dc motors cant use this?

@@haziedabnuuy correct

That would be from the Random Carrier Frequency Modulation(RCFM) which is quite rare to find in GTO-VVVF drives, I think a few Alstom Pendolinos have it too but besides that, this might be the only GTO with RCFM to my knowledge.

Oh thanks

Is there pcfm gto vvvf

@@minecraft_javjavatonkoonca8109 Yes! Theres a good number of PCFM GTO-VVVF in fact produced by companies such as Toyo Denki and Holec just to name a few, most of which are found in either Europe or Japan.

Thanks

This doesn’t apply to chopper. Only AC

@@QuarioQuario54321 That’s incorrect. The chopper generates a PWM frequency that can be picked up by an inductor. Resistance/cam control cannot be recorded because it is changing the voltage with resistors rather than using PWM.

​@@HIDLad001 But author can try to record the camshaft changing positions and contactors clicking😊 But i agree, DC thyristor control can be recorded clearly just like an AC traction, because both systems use PWM and pulsing current on the output to the motors.

I tried 5 years ago, however failed to get the ideal sound (smooth transition from async to 1P with less noise). Instead, you can refer to this video posted by other creator: ua-cam.com/video/gpLRxpE3gSs/v-deo.html

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.

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.

@@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.

⁠@@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.

@@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.

いやぁ、乗れなかったです💦