Elvas Tower: Dynamic brake features - Elvas Tower

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Dynamic brake features Rate Topic: -----

#16 User is offline   darwins 

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Posted 18 September 2023 - 12:34 AM

Looks good. So many brake controllers that would be useful for. Also some throttles and some gear changes and maybe some other controls.

#17 User is offline   pschlik 

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Posted 18 September 2023 - 06:12 AM

Custom labels would be a great thing to have. It's all too easy to find situations where the default notch text isn't what you need.

#18 User is offline   akioyamamura 

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Posted 04 October 2023 - 06:31 PM

Another cool feature would be a delay between the controller and the brake effort, since the brake reacts in realtime what is unreal.
Something similar to the RateOfChangeUpRPMpSS and RateOfChangeDownRPMpSS would be great to simulate this behavior.

#19 User is offline   darwins 

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Posted 01 November 2023 - 05:43 AM

Thanks. It seems this is working for train brakes like this:

Brake_Train ( 0 1 0.01 0.50
NumNotches ( 5
 Notch ( 0.0 0 TrainBrakesControllerOverchargeStart ORTSLabel ( "RELEASE" ) )
 Notch ( 0.2 0 TrainBrakesControllerReleaseStart ORTSLabel ( "RUNNING" ) )
 Notch ( 0.5 0 TrainBrakesControllerHoldLappedStart  ORTSLabel ( "LAP" ) )
 Notch ( 0.7 0 TrainBrakesControllerFullServiceStart ORTSLabel ( "APPLY" ) )
 Notch ( 1.0 0 TrainBrakesControllerEmergencyStart ORTSLabel ("EMERGENCY") ) ) )


but not for independent brakes like this:

 Brake_Engine ( 0 1 0.1 0
NumNotches ( 4
 Notch ( 0.0   0 EngineBrakesControllerReleaseStart ORTSLabel ( "RUNNING" )
 Notch ( 0.3   0 EngineBrakesControllerHoldLappedStart ORTSLabel ( "LAP" )
 Notch ( 0.7  0 EngineBrakesControllerApplyStart ) ORTSLabel ( "SLOW APPLICATION" )
 Notch ( 1.0  0 EngineBrakesControllerEmergencyStart ) ORTSLabel ( "QUICK APPLICATION" ) ) ) )


#20 User is offline   Weter 

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Posted 10 September 2024 - 10:38 AM

Hello.
I have missed this discussion somehow.
May I know: is it documented anywhere? or can it be documented.
Is it included to testing version's code already?
Or, at least, what all numbers mean:
0 (
0 0
300km/h 0
)

#21 User is online   Albertosaurio65 

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Posted 11 September 2024 - 08:38 AM

0 (                   //Throttle %
            0 0            //speed vs force (m/s - N)
            300km/h 0     //speed vs force (kmh - N)
        )


For things like this:
Attached Image: Sin título.jpg

#22 User is offline   Weter 

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Posted 11 September 2024 - 08:46 AM

Thanks, Alberto,
Do I catch it right, these are minimal (zero) speed and Maximal speed to force ratio pairs for every lever's position, which form each "table's" entry?

#23 User is offline   cesarbl 

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Posted 25 October 2024 - 08:08 AM

I would like to propose yet a new feature regarding train dynamic brake blending. Typically, dynamic braking is not effective at low speeds. Thus, when the train brake controller demands an amount of dynamic braking, the resulting dynamic brake force would be quite low. This could be quite disturbing since the braking force is suddenly reduced. To avoid this, some locomotives replace this dynamic brake with engine brakes at low speeds.

Implementing this has been in my mind for some time, but I thought it was rather specific. However, this function has been implemented by at least 3 european manufacturers: Alstom, Bombardier and CAF.

I now have a working beta for this. It would be activated by a single token to be added in the engine section of the .eng file. I propose one of the following names for the token:

- ORTSTrainDynamicBlendingAirReplacement
- ORTSDynamicBrakesReverseBlending

Choosing an adequate name for the feature is more difficult than the implementation, so any feedback is welcome.

#24 User is offline   Csantucci 

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Posted 25 October 2024 - 08:29 AM

My 5 cents: ORTSDynamicBrakeReplacementWithEngineBrake

#25 User is offline   Weter 

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Posted 25 October 2024 - 08:43 AM

Hello.
Looks like long-awaited feature.
Not only locomotives, but electric commuter trains, metro EMU and trams widely use this.
Sometimes (and most usually), it's actuated by further dynamic brake's range notch (before "Emergency"), called, say, "TR"; sometimes this is added automatically, according to DB's current drop.

Anyway, this is called here "Substitution of dynamic brake", also, electropneumatic valve, responsible for adding friction brakes in that case is called "Substitution valve".

Thanks for Your labors, Cesar!

#26 User is offline   railguy 

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Posted 25 October 2024 - 09:36 AM

I would advise using care about adopting this as a "blanket" feature. Over 50 years ago, the D&RGW railroad (the "Rio Grande") was using modified low-speed dynamic braking on some of its locomotives assigned to low-speed, but heavy-grade branch line service. Also, I believe that AC traction locomotives' dynamic brakes are more effective than DC traction dynamic brakes at low speeds.

#27 User is offline   Weter 

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Posted 25 October 2024 - 09:43 AM

Hello.
Indeed - I just forgot to mention that in my post - AC powered systems, supplied by VFD's allow to decelerate AC motors down to complete stop, and even to hold them stationary against train's weight on grades - so friction brakes are only needed as parking, spare, or emergency.

But I'd not be worried: if said new parameter is omitted - we can set whatever DB characteristics (min usable speed, max force, curves), which we need to get.

#28 User is offline   cesarbl 

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Posted 25 October 2024 - 10:22 AM

Thanks Carlo, I adopted your naming. The feature is now available in the Unstable release.

Quote

I would advise using care about adopting this as a "blanket" feature. Over 50 years ago, the D&RGW railroad (the "Rio Grande") was using modified low-speed dynamic braking on some of its locomotives assigned to low-speed, but heavy-grade branch line service. Also, I believe that AC traction locomotives' dynamic brakes are more effective than DC traction dynamic brakes at low speeds.


Don't worry, the feature is disabled by default. Anyway, it is difficult to trigger this behaviour in existing stock, because it requires a train brake controller which also commands dynamic brakes on MUed locomotives, which is a recently implemented feature.

All the MU trains where I've seen this behaviour have AC motors, so it seems they are still not capable of completely stopping the train.

#29 User is offline   engmod 

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Posted 25 October 2024 - 12:48 PM

>VFD's allow to decelerate AC motors down to complete stop, and even to hold them stationary against train's weight on grades

AC dynamic can apply force ONLY when moving, cannot hold anything stationary.

AC can only apply force ( current ) when the applied waveform leads or lags the load.

#30 User is offline   Weter 

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Posted 25 October 2024 - 01:50 PM

I've meant AC motors and "drives", not Alternating Current itself:
Direct current, applied to two of three phases/coils gives said effect.
Schneider Electrics call this "DC injection"
I guess, You mean "rotating" magnetic field effect, which allows rotation or "generator deceleration", possible even with usual "direct" connection of motor to supply. VFDs, or contactor-based control units, featuring rectifiers and, when needed, braking resistors.

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