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Maximum Dynamic Braking Effort For AC4400CW Locomotives?

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    Maximum Dynamic Braking Effort For AC4400CW Locomotives?

    Has anyone got a reliable reference for the maximum dynamic braking effort for AC4400CW locomotives?

    So far, I can't seem to find the dynamic braking specs for the AC4400CW by searching on the web.

    #2
    Should be 98,000 lbf @20 MPH. Looked through my operators manual for it. Here's a page out of it if you need further confirmation.

    Click image for larger version

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    Comment


      #3
      Thank you very much for this!

      Much appreciated!!

      Comment


        #4
        If I was to put this information in to a ORTSDynamicBrakeCurve file, how would it look?

        Comment


          #5
          Originally posted by OSRFan View Post
          If I was to put this information in to a ORTSDynamicBrakeCurve file, how would it look?
          Using Joe Realmuto's Dynamic Brake Calc. Spreadsheet .... like this:

          Code:
          Comment ( Open Rails Dynamic Brake Curves for AC4400CW --- Mass 417776lbs = 189.5t )
          Comment ( Max Dynamic Braking Effort = 98039lbs )
          Comment ( Dynamic Brake Curves courtesy of Joe Realmuto's Dynamic Brake Calc. Spreadsheet )
          
          ORTSDynamicBrakeForceCurves (
          0.10 ( 0.00 0
          2.24 0
          2.32 43610
          6.23 43610
          7.57 35884
          8.92 30479
          10.26 26489
          11.60 23424
          12.94 20996
          14.29 19025
          15.63 17388
          16.97 16014
          18.31 14839
          19.66 13825
          21.00 12944
          22.34 12166
          23.68 11476
          25.03 10858
          26.37 10307
          27.71 9808
          29.05 9355
          30.40 8941
          31.74 8563
          33.08 8216
          35.32 0 )
          
          0.20 ( 0.00 0
          2.24 0
          2.41 87220
          6.23 87220
          7.57 71763
          8.92 60958
          10.26 52978
          11.60 46849
          12.94 41991
          14.29 38046
          15.63 34776
          16.97 32027
          18.31 29679
          19.66 27650
          21.00 25884
          22.34 24327
          23.68 22948
          25.03 21716
          26.37 20613
          27.71 19612
          29.05 18709
          30.40 17882
          31.74 17126
          33.08 16432
          35.32 0 )
          
          0.30 ( 0.00 0
          2.24 0
          2.50 130830
          6.23 130830
          7.57 107642
          8.92 91433
          10.26 79467
          11.60 70273
          12.94 62982
          14.29 57066
          15.63 52164
          16.97 48036
          18.31 44518
          19.66 41475
          21.00 38824
          22.34 36493
          23.68 34425
          25.03 32574
          26.37 30920
          27.71 29421
          29.05 28059
          30.40 26823
          31.74 25688
          33.08 24643
          35.32 0 )
          
          0.40 ( 0.00 0
          2.24 0
          2.59 174440
          6.23 174440
          7.57 143522
          8.92 121912
          10.26 105957
          11.60 93697
          12.94 83978
          14.29 76087
          15.63 69552
          16.97 64050
          18.31 59353
          19.66 55300
          21.00 51764
          22.34 48655
          23.68 45897
          25.03 43432
          26.37 41222
          27.71 39224
          29.05 37414
          30.40 35759
          31.74 34247
          33.08 32859
          35.32 0 )
          
          0.50 ( 0.00 0
          2.24 0
          2.68 218050
          6.23 218050
          7.57 179401
          8.92 152387
          10.26 132446
          11.60 117117
          12.94 104969
          14.29 95107
          15.63 86936
          16.97 80059
          18.31 74192
          19.66 69125
          21.00 64704
          22.34 60816
          23.68 57369
          25.03 54291
          26.37 51528
          27.71 49033
          29.05 46769
          30.40 44700
          31.74 42810
          33.08 41075
          35.32 0 )
          
          0.60 ( 0.00 0
          2.24 0
          2.77 261660
          6.23 261660
          7.57 215281
          8.92 182866
          10.26 158935
          11.60 140542
          12.94 125965
          14.29 114128
          15.63 104324
          16.97 96073
          18.31 89031
          19.66 82950
          21.00 77644
          22.34 72982
          23.68 68845
          25.03 65149
          26.37 61835
          27.71 58837
          29.05 56119
          30.40 53641
          31.74 51372
          33.08 49286
          35.32 0 )
          
          0.70 ( 0.00 0
          2.24 0
          2.86 305270
          6.23 305270
          8.92 213341
          10.26 185424
          11.60 163966
          12.94 146960
          14.29 133149
          15.63 121712
          16.97 112082
          18.31 103866
          19.66 96775
          21.00 90588
          22.34 85143
          23.68 80317
          25.03 76007
          26.37 72137
          27.71 68645
          29.05 65473
          30.40 62582
          31.74 59935
          33.08 57502
          35.32 0 )
          
          0.80 ( 0.00 0
          2.24 0
          2.95 348880
          6.23 348880
          7.57 287039
          8.92 243820
          10.26 211913
          11.60 187390
          12.94 167951
          14.29 152169
          15.63 139100
          16.97 128095
          18.31 118705
          19.66 110596
          21.00 103528
          22.34 97305
          23.68 91789
          25.03 86865
          26.37 82443
          27.71 78449
          29.05 74824
          30.40 71518
          31.74 68494
          33.08 65714
          35.32 0 )
          
          0.90 ( 0.00 0
          2.24 0
          3.04 392490
          6.23 392490
          7.57 322919
          8.92 274295
          10.26 238398
          11.60 210810
          12.94 188947
          14.29 171190
          15.63 156484
          16.97 144109
          18.31 133544
          19.66 124421
          21.00 116468
          22.34 109471
          23.68 103265
          25.03 97723
          26.37 92750
          27.71 88257
          29.05 84178
          30.40 80459
          31.74 77057
          33.08 73929
          35.32 0 )
          
          1.00 ( 0.00 0
          2.24 0
          3.13 436100
          6.23 436100
          7.57 358798
          8.92 304774
          10.26 264887
          11.60 234234
          12.94 209938
          14.29 190210
          15.63 173872
          16.97 160118
          18.31 148379
          19.66 138246
          21.00 129408
          22.34 121632
          23.68 114737
          25.03 108581
          26.37 103056
          27.71 98061
          29.05 93533
          30.40 89400
          31.74 85619
          33.08 82145
          35.32 0 )
          )​
          Cheers, Gerry
          "A mind is like a parachute. It doesn't work if it is not open." Frank Zappa
          It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.
          Forever, ridin' drag in railroad knowledge.
          Audi, Vide, Tace, Si Vis Vivere In Pace

          Comment


            #6
            Originally posted by R. Steele View Post
            Using Joe Realmuto's Dynamic Brake Calc. Spreadsheet
            I have that, but am not able to figure out how to get some of the parameters. Is there a tutorial on its use.

            Comment


              #7
              Originally posted by OSRFan View Post
              Is there a tutorial on its use.
              Not that I know of....in the thread at Elvas Tower where the Dynamic Brake Calc Spreasheet is posted there is also a pdf manual "Guideline For Setting Open Rails Braking Parameters" which may be helpful.

              As you know the Dynamic Brake Calc, requires these variables to calculate the curves: Max Speed, Fading Speed, Minimum Speed, Taper Speed, Max Dynamic Brake Power and Max Dynamic Brake Effort. If you can't find these specs in a manual or design doc ( which is hard sometimes ) you can try the MSTS engine file....but many times those values are wrong in the msts eng file.
              For instances -- here's a section from an AC4400 eng file for Dynamic brakes --- notice the max speed before fade out = 470 !!! (probably more like 60-70 ). MinUsableSpeed is probably close.

              Code:
              DynamicBrakesMinUsableSpeed( 3.5 )
              DynamicBrakesMaximumEffectiveSpeed( 26 )
              DynamicBrakesMaximumForce( 332.28kN )
              DynamicBrakesResistorCurrentLimit ( 900 )
              DynamicBrakesCutInSpeed( 6.5 )
              DynamicBrakesMaxAirBrakePressure ( 50 )
              DynamicBrakesFadingSpeed( 7 )
              DynamicBrakesDelayTimeBeforeEngaging ( 7 )
              DynamicBrakesMaximumSpeedForFadeOut ( 470 )
              DynamicBrakesEffectAtMaximumFadeOut( 0 )
              DynamicBrakesHigherSpeedCurveExponent( 10.4 )
              DynamicBrakesLowerSpeedCurveExponent( 0.9 )
              DynamicBrakesNumberOfControllerNotches( 1 )
              DynamicBrakeHasAutoBailOff ( 1 )​
              I was provided a "Rule of Thumb" for the following two variables you need, Max Dynamic Power and Force:
              1. To find approximate Dynamic Brake power: 75% to 83% of tractive HP

              2. To find approximate Dynamic Brake effort: ( + Amp Load not modeled in OR? ) -- 50% to 60% of STE​
              Here's a set of curves ( AC4400 ) from the spreadsheet Calc. I'm still learning this stuff also, constantly evaluating old results, and refining them as I learn more.

              Click image for larger version

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              Click image for larger version

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ID:	2315816

              Hope some of this helps....if anyone has accurate Dynamic Brake specifications for specific locomotives, please post in this thread.
              Cheers, Gerry
              "A mind is like a parachute. It doesn't work if it is not open." Frank Zappa
              It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.
              Forever, ridin' drag in railroad knowledge.
              Audi, Vide, Tace, Si Vis Vivere In Pace

              Comment


                #8
                Thanks for that Gerry. I'll mess around with this on some of my locos and see what the results are.

                I have the "Guideline For Setting Open Rails Braking Parameters" which I use frequently. Generally revamp the brake physics for everything I download according to this guide.

                Comment


                  #9
                  The dynamic brake power on a 6 motor GE AC will generally be around 5200 horsepower or 6000 horsepower (higher power option comes with an extra set of grids and blowers to handle the extra heat dissipation-see the 3D model of the unit used), 3600 horsepower is quite the underestimate and won't make driving any easier! Remember, these things (and a majority of other modern units) can self-load, putting the entire power output of the main generator into the dynamic brakes, which requires dynamic brakes that can handle more power than the locomotive's rating.
                  ​​​
                  ​Contributing to ORTS on GitHub as SteelFill

                  Comment


                    #10
                    Originally posted by pschlik View Post
                    Remember, these things (and a majority of other modern units) can self-load, putting the entire power output of the main generator into the dynamic brakes, which requires dynamic brakes that can handle more power than the locomotive's rating.
                    OR doesn't model self loading -- or amperage ----
                    Originally posted by R. Steele View Post
                    ( + Amp Load not modeled in OR? )
                    correct? The "rule of thumb" probably applies with a little more accuracy to older models.... anyway ... thanks for posting, accurate information is always good to have.

                    One other question" I've never understood what the dynamic brake "taper speed" referred to, or found it in specifications.
                    Cheers, Gerry
                    "A mind is like a parachute. It doesn't work if it is not open." Frank Zappa
                    It's my railroad and I'll do what I want! Historically accurate attitude of US Railroad Barons.
                    Forever, ridin' drag in railroad knowledge.
                    Audi, Vide, Tace, Si Vis Vivere In Pace

                    Comment

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