Amtrak trains

rrman posted:

Noticed that Amtrak head end prime mover runs full throttle, does its shaft turn two separate alternators, one for the traction (assume AC motors controlled by electronics) and other for train 480V three phase power,

Generally, yes. Two separate generators. Thus, when the unit is NOT providing HEP, the prime mover has the standard 8 throttle steps and associated engine speed changes.

or is alternator a single "hunk of iron" unit with two separate winding power outputs? 

Hot Water posted:

rrman posted:

Noticed that Amtrak head end prime mover runs full throttle, does its shaft turn two separate alternators, one for the traction (assume AC motors controlled by electronics) and other for train 480V three phase power,

Generally, yes. Two separate generators. Thus, when the unit is NOT providing HEP, the prime mover has the standard 8 throttle steps and associated engine speed changes.

or is alternator a single "hunk of iron" unit with two separate winding power outputs? 

 

Thanks HW.

We rode the City of New Orleans to Jackson (flood concerns on the RR wooden causeway) then bussed rest of way to New Orleans Amtrak station.  Thats when I became aware that prime mover seems to be running notch 8 all day long, but made sense that it would need to to keep the power constant to train (DUH!), while those "educated semiconductors" took care of traction matters.

rrman posted:

Hot Water posted:

rrman posted:

Noticed that Amtrak head end prime mover runs full throttle, does its shaft turn two separate alternators, one for the traction (assume AC motors controlled by electronics) and other for train 480V three phase power,

Generally, yes. Two separate generators. Thus, when the unit is NOT providing HEP, the prime mover has the standard 8 throttle steps and associated engine speed changes.

or is alternator a single "hunk of iron" unit with two separate winding power outputs? 

 

Thanks HW.

We rode the City of New Orleans to Jackson (flood concerns on the RR wooden causeway) then bussed rest of way to New Orleans Amtrak station.  Thats when I became aware that prime mover seems to be running notch 8 all day long, but made sense that it would need to to keep the power constant to train (DUH!),

Actually it is a bit simpler than that. The prime mover RPM must be maintained at a constant speed in order to ensure that any and all clock on the train keep the correct time, i.e. 60 HZ. No different than your clocks at home.

while those "educated semiconductors" took care of traction matters.

Hot Water posted:

rrman posted:

 Thats when I became aware that prime mover seems to be running notch 8 all day long, but made sense that it would need to to keep the power constant to train (DUH!),

Actually it is a bit simpler than that. The prime mover RPM must be maintained at a constant speed in order to ensure that any and all clock on the train keep the correct time, i.e. 60 HZ. No different than your clocks at home.

 

 

That's interesting.  Hadn't considered needing to have 60Hz for anything on board, but guess if the cars have timers for various functions you would need that frequency so things don't get too far out of time sequence.