GE U Boat electrical generation question

[uhaul]

Why did the U-boats trip ground relays at top speed? Was it just the U36Bs or any U-boat 4 axle or 6 axle in general that tripped ground relays at top speed?

Happy New Year

[DutchRailnut]

The Early GE's just did, untill GE stated using Alternators in their B23-7's at High speed the voltage just got to high at generator end and any dust or moisture made them trip.

[John_Perkowski]

Amtrak Forum Moderator Note:

I'm sending this to the GE Locomotive Forum for more opportunities for a detailed answer.

[DutchRailnut]

Just Explanation, the question came up when someone stated that the U-boats on original Auto train operation did 75 mph (according to trains magazine) where someone with timetable info said max speed was 70.

[.Taurus.]

what happens when "ground relays trip" ?
cause it to problems with the wayside signals?
Bye

[DutchRailnut]

no it just drops load on engine and if engineer leaves throttle in 7 or 8 notch the main engine shuts down.

[LCJ]

The ground relay does two things -- it reduces diesel engine speed to idle, and cuts off the generator field current (which unloads the generator, cutting off high voltage current to the traction motors). The ground relay does not shut down the engine no matter what position the throttle is in.

On occasion, though, there may be an overspeed shutdown of the engine caused by the sudden loss of generator load.

[.Taurus.]

Ah
the ground relay isn't located at the ground besides the tracks but is inside the u-boat and the word 'ground' is a electro technical term

[LCJ]

The ground relay acts as an interrupter for the traction high voltage system, tripping whenever there is a fault (short circuit) in the main generator, or the traction motors, or the connections between the the generator and the traction motors. These faults are often caused by the build up of dirt or small pieces of wire broken off from the windings.

Without this device, a short circuit would very quickly turn into a fire!

[GN 599]

A fellow engineer thats been around a while told me a good way to screw an Alco up was to throw a U-Boat in the consist. For some reason or another the Alco's electrical system didnt mesh well with GE.

[GOLDEN-ARM]

A fellow engineer thats been around a while told me a good way to screw an Alco up was to throw a U-Boat in the consist. For some reason or another the Alco's electrical system didnt mesh well with GE.

Seems the best way to screw up ANY consist.........

[Luther Brefo]

A fellow engineer thats been around a while told me a good way to screw an Alco up was to throw a U-Boat in the consist. For some reason or another the Alco's electrical system didnt mesh well with GE.

Never heard such a thing...please explain...

[DutchRailnut]

yup that would be weird as ALCO uses a GE electrical system for about 90% of components.

[Luther Brefo]

yup that would be weird as ALCO uses a GE electrical system for about 90% of components.

My thoughts exactly...

[LCJ]

My personal experience (oh so many years ago now) with early U-series GE units was that they played havoc with controlling the train when mixed in with other types.

Early U25s had a simple, load regulator type of throttle control, with no feedback loops for horsepower for any one throttle position. This means that as speed reduced under power, even with the throttle reduced to lower notches, load would continue to increase tremendously.

If you had one of these in the lead, you could see it on the ammeter. If it was back in a mixed consist, you had no idea what those units were doing back there as the train speed reduced down to a stop under power (yes, power braking -- we used to do that all the time).

If you weren't careful, you could yank the guts out of the end of a car.

Just another reason I never liked the early Erie, PA attempt at building diesel-electric locomotives.