[superheatedsteam]

Thanks to you all for the responses. This confirms my suspicion that the 10 second imposed wait period in MSTS and OR is incorrect, on US based locomotives at least. Should we ask for it to be removed? Does that impact dynamic brakes for locomotives from other nations?

I would still like confirmation on the other issue, where the default MSTS SD40-2 and GP38-2 dynamic brake animations appear to function correctly and in sync with keyboard inputs in MSTS but not so in OR.

Cheers,

Marek.

[R H Steele]

 superheatedsteam, on 19 July 2021 - 08:10 AM, said:

Thanks to you all for the responses. This confirms my suspicion that the 10 second imposed wait period in MSTS and OR is incorrect, on US based locomotives at least. Should we ask for it to be removed? Does that impact dynamic brakes for locomotives from other nations?

I would still like confirmation on the other issue, where the default MSTS SD40-2 and GP38-2 dynamic brake animations appear to function correctly and in sync with keyboard inputs in MSTS but not so in OR.

Cheers,

Marek.

Pardon me, I am confused,

Quote

This confirms my suspicion that the 10 second imposed wait period in MSTS and OR is incorrect

--- have you read post#16 which explicitly states that a 10 second delay period was in use? Or am I missing some pertinent point here?

[vince]

The 10 second delay is to allow the traction motor power relays to do their change from power to dynamic braking and per the UP engineer I spoke to several years back has pretty much always been this way.

regards,
vince

[Weter]

Quote

... the 10 second imposed wait period in MSTS and OR is incorrect, on US based locomotives at least. Should we ask for it to be removed?

Please, see post #12: it seems to me, we can do it without removing anything-just re-defining the delay timeout to zero.

If we recall the MSTS manual, we'll see there: this 10 seconds is needed for current in system to disappear completely before DB can really de engaged.
I composed a kind of verbose answer this morning. Wants anyone to read it?

[ebnertra000]

I would advocate an enforced delay as an optional feature, to be decided by locomotive type, since some did have it, though it should really be while in idle, rather than in setup

[R H Steele]

 ebnertra000, on 19 July 2021 - 11:56 AM, said:

I would advocate an enforced delay as an optional feature, to be decided by locomotive type, since some did have it, though it should really be while in idle, rather than in setup

Maybe so, in that case, I think it should be given an ORTS parameter so a user can code their locomotives for the delay. The MSTS parameter is "DynamicBrakesDelayTimeBeforeEngaging" -- so maybe ORTSDynamicEngageTimeDelay ( seconds )

...and in this case: ORTSDynamicEngageTimeDelay ( 0 ) --- there would be no time delay and the MSTS parameter would be ignored.

[superheatedsteam]

Thanks for pointing out the DynamicBrakesDelayTimeBeforeEngaging ( x ) parameter. I changed this from 10 to 0 and there is no longer the forced 10 second restriction in moving the dynamic lever.

If someone could still compare MSTS to OR dynamic lever cab animations using the default SD40-2 and/or GP38-2 and report back, that would be appreciated.

Cheers,

Marek.

[Weter]

And the current can't disappear immediately, so hiatus is needed BEFORE the scheme will be switched from traction mode to dynamic braking, then such switching itself must be performed, that takes some time as well.
For instance, let's take, the generator de-magnitizes during 6 seconds; the relays change the scheme, and contractors shutting - at 4 seconds.
You have to set throttle to idle, after 6s the current will disappear completely, then you set DB notch, and after 4 seconds, the scheme will be re-assembled. Total we have that 10s delay. If you coasted at idle before, that 6 seconds were expired already, hence the setup of the scheme will take only 4 seconds this time.
If you will try to switch power contacts under strong current, they will be damaged by electric arcs, so their resource would be shortened significantly, the voltage may jump rather high, damaging the entire scheme's components and insulation. hence the scheme is probably has a time-delay component for forced preventing of too early switching, as it was said at some post above.
https://m.youtube.co...h?v=PXiOQCRiSp0

In common words, the current is always tend to continue flowing (in our case). This is much similar to mechanical inertia, when the body, which gained speed is tend to maintain it and not stops immediately, or can't be accelerated to high speed at once. The inertia depends on mass. In case of electricity, we have an inductivity instead of inertia. It depends on quantity of charged particles. If you will try to interrupt the current flow, it will try to keep on flowing. That's why the generator's current needs some time to disappear, and why if the contacts will be opened under current, the electric arc will appear, melting and eroding metal from contacts surfaces. As with arc welding.
Free electrons are grabbed by magnetic field in generator, so until that field will fade-out completely, the current will be supported this way too.
As well, to maintain itself between opened contacts, it causes the voltage jerk, that can be very significant in case of hi inductive equipment.

[DirtyRam]

 Weter, on 19 July 2021 - 11:44 AM, said:

If we recall the MSTS manual, we'll see there: this 10 seconds is needed for current in system to disappear completely before DB can really de engaged.
I composed a kind of verbose answer this morning. Wants anyone to read it?

Hey Weter, you are correct. When under power the motors spin in one direction, when in DB they turn the other way. Hence resistance. They need to stop spinning before they can turn opposite way. That 10 second rule was imposed by the railroads so traction motors wouldn't get beat and burned up. Thats what CN taught us when I trained as an Engineer in the early 90s.

Mike

[Weter]

Excuse me, but not motors, but the current in their coils.
That, what you said is completely right for the case, when someone tries to change revercer, before engine complete stop:
Applying to the motors the current with an opposite direction will produce very high voltage in power circuits, as the motors will be exalted and will start generating an additional voltage, that will sum with applied voltage.

This way, in distinction of counter-steam braking, counter-current application is unacceptable for safety reasons-it will be effective, but will damage the scheme.