Elvas Tower: Dynamic Brake (kW) aka wheelslip - Elvas Tower

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Dynamic Brake (kW) aka wheelslip Rate Topic: -----

#1 User is offline   Stijn D.C. 

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Posted 15 July 2017 - 09:49 AM

Hello,

On a techical fiche of a High speed train (2 locomotives + 8 carriages) stay: "1 884 kW at wheel rim per bogie" (In case of Dynamic brakepower)

1 loc have 2 bogies in this case = 2X 1884 kw = 3768kW

For a ENG file must i give value in KiloNewtons

I'am not chur of 376,8kN is right value in this case.


If i use 376,8kN on 45% i have wheelslip. In real , if it is dry, good adhesension... you can set dynamic brake lever to 100% without wheelslip.

Advanced Adhes. is not active on this tests, and the values of my settings are: 130% (adh. factor) & 10% Adh. factor random change

ORTSCurtius_Kniffler ( 7.5 44 0.161 0.7 )

With 150kN i have not wheelslip


Data of Dynamic brakes:

comment(-------- Frein électrique --------)

DynamicBrakesMinUsableSpeed ( 20 )
DynamicBrakesMaximumEffectiveSpeed ( 25 )
DynamicBrakesMaximumForce ( 188.4kN )
DynamicBrakesResistorCurrentLimit ( 1500 )
DynamicBrakesCutInSpeed ( 15 )
DynamicBrakesMaxAirBrakePressure ( 15 )
DynamicBrakesFadingSpeed ( 20 )
DynamicBrakesDelayTimeBeforeEngaging ( 0.5 )
DynamicBrakesMaximumSpeedForFadeOut ( 1800 )
DynamicBrakesEffectAtMaximumFadeOut ( 0 )
DynamicBrakesHigherSpeedCurveExponent ( 13.5 )
DynamicBrakesLowerSpeedCurveExponent ( 0.9 )
DynamicBrakesNumberOfControllerNotches ( 20 )
DynamicBrakeHasAutoBailOff ( 1 )

ORTSDynamicBlendingOverride ( 1 )
ORTSDynamicBlendingForceMatch ( 1 )


In advance thanks

#2 User is offline   ErickC 

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Posted 28 July 2017 - 09:27 AM

The problem is that a newton is a very different unit than a kilowatt. A newton is a unit of force, a kilowatt is a unit of power. If we're talking about rotational power, such as the power of an engine, we could convert kilowatts to newton-meters (torque) based on the relationship between torque, power, and rotational speed, but that still won't yield a number expressed in newtons. We could also convert kilowatts to newton-meters per hour or second or whatever unit of time you'd like. But that won't give us what OR wants, either. Dynamic brakes do produce a definite maximum retarding force, but that can't be expressed in kilowatts, because it's a force, not power. Power is work multiplied by time, work is force multiplied by distance. You can start to see all the other things we'd need to know to get any meaningful data out of that power rating.

I've seen estimates that dynamic braking force is generally somewhere between 10,000 and 15,000 pounds per axle (with more modern locomotives being on the higher end of the scale). Maybe that might be a good starting point for a guesstimate if the operator manual doesn't provide the necessary data?

#3 User is offline   Coolhand101 

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Posted 28 July 2017 - 03:52 PM

If the engine/trainset in question uses a blended dynamic brake. As in the real world, the dynamic brake will try and achieve the required brakeforce. If it cannot, the airbrake will intervene as well, to get the desired brake rate.

There is hardly any difference in brakeforce for the dynamic and airbrake for these type of trainsets.

For my class 86 electric loco, i do add 10% more than the air brakeforce, as the dynamic brake can 'bite' better than the disc brake.

Thanks

#4 User is offline   engmod 

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Posted 28 July 2017 - 04:16 PM

You need to specify the mass of the engines, this affects the tractive effort and dynamic brake forces.

#5 User is offline   Stijn D.C. 

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Posted 30 July 2017 - 03:53 PM

The most locomotives in my country or where i work on it have both (Dynamic brake with lever) and with blendedbutton.


But for trains that brake on engines/motor, blended used too (blended en dynamiccommands in ORTS is not ok for moment => Trelloreport sended few weeks ago)


Yes by blended in real a system handle the pneumatic air and dynamic tension


But i think my theory that 5000kw is 500Kn example is not right. :10 is not the right formule.


The train in my first post is a High speed train. by 150 à 160 kN is ok, but if i use value 320kN it is slipping.

I have see a movie of a cabride where a traindriver set that dynamic brake to 100% without slipping (dry weather).

A friend of me drive with TGV and he said that it is true, but if the rails are wet, dirty by dry weather it can sometime give slip, by rain and snow it is no possible to do 100% dynamic power.


The values in Kw comes from the technical fiches.

#6 User is offline   Stijn D.C. 

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Posted 03 October 2017 - 06:52 AM

Hello

Topicupdate

In a handbook of a locomotive (buildingyear 1998) i have read something usefull

This locomotive have 150kN dynamic tension in case/based on UIC rules.


But the best comes... If this locomotive drives in TrainSwitch/MU (2 locomotives in service), the MPU (computer) of this train gonna make

that both locomotives gives 75kN. This must we can do in ORTS too with ENG file command


Becauze now if you have 2 locomotives with 150kN, ORTS dont take 75kN, but 300kN


That is reason why on TGV trains or consist with more locomotive is quick wheelslip


In some cases the full kN of both locomotives need, me suggestion for this, is that there is command for locomotives that calculate on each loc in service


If it is possible to make that in the code, i advise this commandrule for the .ENG file


ORTSDynamicTensionCalcIfLocomotiveInMUConnection ( 1 )


My case is on a consist with 2 locomotives of same serie

The formule for this is Dynamicpower of playerlocomotive where cabine is active /2

If there are 3 locomotives it must be that 150kn is devided on 3 = 50kN Dynamic power on each locomotive


In advance thanks,

Stijn

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