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M-9 Discussion


East New York

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3 minutes ago, EphraimB said:

Will the R211s propulsion sound similar?

There's no way to know that right now.

However, I love the propulsion here. It sounds like the M7 and M8 packages did the fusion dance and we got this.

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27 minutes ago, RailRunRob said:

What type of propulsion are they using  with the M9's ? Mitsubishi again?

Yep, M7-M9 all use Mitsubishi, its easier to swap parts that way. I believe everything is the same just the inverters are tuned differently on each unit.

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31 minutes ago, jamesman8 said:

Yep, M7-M9 all use Mitsubishi, its easier to swap parts that way. I believe everything is the same just the inverters are tuned differently on each unit.

The M8's are a bit more complex I take it... with three different voltage types.. Multiple propulsion systems.

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4 hours ago, RailRunRob said:

The M8's are a bit more complex I take it... with three different voltage types.. Multiple propulsion systems.

Technically no. Still one propulsion system, but the power transmission system is more complex. Regardless of the power supply rating, the input to the traction inverters is always the same. The onboard transformer takes care of the voltage / frequency changes.

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28 minutes ago, Fan Railer said:

Technically no. Still one propulsion system, but the power transmission system is more complex. Regardless of the power supply rating, the input to the traction inverters is always the same. The onboard transformer takes care of the voltage / frequency changes.

So the difference in sound between the three is because of the difference in voltage?

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1 hour ago, Around the Horn said:

So the difference in sound between the three is because of the difference in voltage?

That wouldn't explain the difference from the M7s sounds, so I want to say no.

It's likely the design of the propulsion systems itself. While they are all made by the same manufacturer, they do update them as time goes on. I would guess that's why the sounds are different.

Because the M9s sound somewhere directly between M7 and M8.

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21 minutes ago, LTA1992 said:

That wouldn't explain the difference from the M7s sounds, so I want to say no.

It's likely the design of the propulsion systems itself. While they are all made by the same manufacturer, they do update them as time goes on. I would guess that's why the sounds are different.

Because the M9s sound somewhere directly between M7 and M8.

That is correct. The quality of sound coming from AC propulsion systems is a direct function of the PWM (pulse-width modulation).

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6 hours ago, Fan Railer said:

Technically no. Still one propulsion system, but the power transmission system is more complex. Regardless of the power supply rating, the input to the traction inverters is always the same. The onboard transformer takes care of the voltage / frequency changes.

What are these guys describing here with  3 propulsion systems? Wouldnt you need an inverter to step from 700V to motor output as well as conversion down from both 12/25kv?  So one box does both inversion and conversion? (DC and AC)?

lGpFzTy.png

Edited by RailRunRob
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30 minutes ago, RailRunRob said:

What are these guys describing here with  3 propulsion systems? Wouldnt you need an inverter to step from 700V to motor output as well as conversion down from both 12/25kv?  So one box does both inversion and conversion? (DC and AC)?

lGpFzTy.png

The three propulsion systems in this conversation are the MELCO packages for the M7, M8, and M9

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14 minutes ago, Around the Horn said:

The three propulsion systems in this conversation are the MELCO packages for the M7, M8, and M9

You know what. Tho rare I have seen like MITRAC systems support both DC and AC.. Like the Electrostar and Eurostar trainsets. So this would be a similar thing I gotcha..

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55 minutes ago, RailRunRob said:

What are these guys describing here with  3 propulsion systems? Wouldnt you need an inverter to step from 700V to motor output as well as conversion down from both 12/25kv?  So one box does both inversion and conversion? (DC and AC)?

The three propulsion systems for the M8 are catenary, and two for the dual current collector.  The M8 collectors can run on overhanging (LIRR) or underhanging (MNR) third rails.  This is because the M8s were designed to be able to run into Penn Station, should that ever happen.

While the M7, M8, and M9 propulsions are all supplied by Melco and all use AC traction motors, there are improvements such as size and different pitch curves that affect the sound of the propulsion.  Let's not forget also that the M7 propulsion package is over 15 years old, and the M8 propulsion package is almost 10 years old.  The electronics of rail cars evolve very, very quickly, and it's the electronics that dictate the propulsion sound.  While the R179s and R160s are very similar in terms of overall design, there are actually many electrical differences between the two.

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9 hours ago, Fan Railer said:

I feel the term "propulsion system" is being used too narrowly here. The entire set up should be referred to as "the system". The system is comprised of different components, some allowing the vehicle to accept different power sources. 

Okay so let's build on that general term of the system it's been a while but if IIRC there's 5-6 major parts and areas of a railcars breakdown. 

  • Motor and gearbox
  • Propulsion 
  • Input inductor
  • Resistors

and i'll add knife switch in there as well. I know within propulsion itself there's some electronics that makeup it's own sub system DCU, VCU's train control ect.  So I get that. The M8's are probably some of most complex cars out there.  Just looking at the weight difference between the cars I know there's some extra hardware. Almost a extra 20,000lbs (10tons) worth.  So my question is around traction and line voltage and how it get's to the motors?. Does the M8 have one traction converter for both AC and DC power or multiple modules or hardware to deal with that?  That's what I was asking.

Edited by RailRunRob
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2 hours ago, RailRunRob said:

Okay so let's build on that general term of the system it's been a while but if IIRC there's 5-6 major parts and areas of a railcars breakdown. 

  • Motor and gearbox
  • Propulsion 
  • Input inductor
  • Resistors

and i'll add knife switch in there as well. I know within propulsion itself there's some electronics that makeup it's own sub system DCU, VCU's train control ect.  So I get that. The M8's are probably some of most complex cars out there.  Just looking at the weight difference between the cars I know there's some extra hardware. Almost a extra 20,000lbs (10tons) worth.  So my question is around traction and line voltage and how it get's to the motors?. Does the M8 have one traction converter for both AC and DC power or multiple modules or hardware to deal with that?  That's what I was asking.

Typically power transmission follows an AC-DC-AC path. This is true for diesel electric locomotives and units drawing AC overhead current. AC power is accepted from the overhead line or the main alternator, rectified to DC for the DC link, which then supplies both the traction inverters (which invert back to AC for the motors) and the HEP and aux inverters (which invert back to AC for those loads).

In the case of DC pickup (third rail or overhead), the power supply bypasses the rectifier and enters the DC link.

In the case where multiple AC sources (different voltage and frequencies) are to be used (like with the M8s and NEC electric locomotives, etc), a transformer is provided to take the input AC and output a standard AC setting to the rectifier for the DC link.

Edited by Fan Railer
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19 minutes ago, Fan Railer said:

Typically power transmission follows an AC-DC-AC path. This is true for diesel electric locomotives and units drawing AC overhead current. AC power is accepted from the overhead line or the main alternator, rectified to DC for the DC link, which then supplies both the traction inverters (which invert back to AC for the motors) and the HEP and aux inverters (which invert back to AC for those loads).

In the case of DC pickup (third rail or overhead), the power supply bypasses the rectifier and enters the DC link.

In the case where multiple AC sources (different voltage and frequencies) are to be used (like with the M8s and NEC electric locomotives, etc), a transformer is provided to take the input AC and output a standard AC setting to the rectifier for the DC link.

2

Gotcha.. I'm familiar with the concept of rectifiers from AC alternators in that path IIRC it's easier to control or Manipulate power this way.. I gotcha that makes more sense.

Edited by RailRunRob
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On ‎6‎/‎28‎/‎2018 at 9:30 PM, EphraimB said:

Then all the low-lives and homeless people will take the LIRR making it what the NYC Subway is today and the good neighborhoods the LIRR serves well become bad just like the Rockaways.

Give me this influx of homeless people that are on the Metro-North, LIRR, or NJ Transit.... I'll wait.....

You think homeless people, en masse, give a shit about service frequency.....

You are the last mother***er I want to hear complaining about infrequent service on any mode of public transit - Including the (A) you suggest having extended to your house..... Have you tell it, whatever mode of mass transit that passes through "good" areas should be kept at subpar headways to keep, you know, the "low-lives and homeless people" from utilizing it - to keep the "good" areas "good"....

People are fed up w/ the declining state of public transit & here you are indirectly advocating for it - All for the sake of a freakin fallacy...

Unreal.

Edited by B35 via Church
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