DE6 "shifting" gears?

[pugdogg55]

What is happening when the DE6 "shifts" for lack of a better term at the moment. I believe that electric motors don't have gears so I'm not sure what's going on.

When I have the throttle fully open to gain speed on straightaways I'll hear a click of some kind and the rpm's and amperage will drop significantly before picking back up. It's not wheelslip and I don't know what else it could be. Has anyone else experienced this?

[cmdr.monkey]

On diesel electric locomotives, they usually have a "transition speed" which feels very much like shifting gears. Depends on the loco, but it's usually around the 20-21mph. It basically is like shifting from pulling to cruising.

[Grem™]

I also experience this in any gear above 3. I decided that this is a bug, in general it does not cause problems.

[freightliner15]

your amps or temp probably to high, should be using notch 2 or 3 for taking off then slowly increase power as the amps and temp drop back down, can only use full throttle once your doing around 70kmh

[schutt]

Its a feature and i foud transitions to be at 35kmh and 58kmh. i am not sure, there could be a 3rd one but i havent been able to find it. so maybe there is only 2.

At low speeds the electric motors pull their max amount of amps already at lower voltages, so the motors are all connected in series which gives you the possibility to open the regulator a little. At higher speeds they get grouped in 2 or 3 groups that are connected parallel, giving more voltage so you can still reach high amp number, above 58 all motors get full voltage to be able to produce more power as they would deliver when in series (all motors parallel).

Thats why on uphill passages it works best if you manage to keep the speed above 35kmh, once you drop below the locomotiv struggles.

If they wouldnt transition then you would fry the traction motors at low speeds with anything over step 1. As it is you at least have step 1 to 6 in the lower power range, while at anything over 3 only for short time since they heat up fast there, so still need to have the regulater at the lower positions untill your in the higher speed regions.

[Buzzzz]

Originally posted by schutt:

Its a feature and i foud transitions to be at 35kmh and 58kmh. i am not sure, there could be a 3rd one but i havent been able to find it. so maybe there is only 2.

At low speeds the electric motors pull their max amount of amps already at lower voltages, so the motors are all connected in series which gives you the possibility to open the regulator a little. At higher speeds they get grouped in 2 or 3 groups that are connected parallel, giving more voltage so you can still reach high amp number, above 58 all motors get full voltage to be able to produce more power as they would deliver when in series (all motors parallel).

Thats why on uphill passages it works best if you manage to keep the speed above 35kmh, once you drop below the locomotiv struggles.

If they wouldnt transition then you would fry the traction motors at low speeds with anything over step 1. As it is you at least have step 1 to 6 in the lower power range, while at anything over 3 only for short time since they heat up fast there, so still need to have the regulater at the lower positions untill your in the higher speed regions.

Very informative answer.. Thank you.

[Knsgf]

Originally posted by schutt:

At low speeds the electric motors pull their max amount of amps already at lower voltages, so the motors are all connected in series which gives you the possibility to open the regulator a little. At higher speeds they get grouped in 2 or 3 groups that are connected parallel, giving more voltage so you can still reach high amp number, above 58 all motors get full voltage to be able to produce more power as they would deliver when in series (all motors parallel).

The above paragraph applies to DC electric locomotives. On diesel electrics TMs cannot output more power than alternator and diesel engine which drives it produce. You might've noticed that TM current on DE6 immediately after transition is virtually the same as it was a moment before it. Thus the power output of TMs also remains almost the same.

Originally posted by schutt:

Thats why on uphill passages it works best if you manage to keep the speed above 35kmh, once you drop below the locomotiv struggles.

Minimum continuous speed on diesel electric is completely unrelated to transitioning.

Originally posted by schutt:

If they wouldnt transition then you would fry the traction motors at low speeds with anything over step 1.

Motors would be fine without transition; you would fry the alternator instead.