MPI HSP46 passenger locomotive, powered by GE GEVO-12

Allen Hazen wrote:Fan Railer--
GE's AC60 freight locomotive is 6,000 hp on six axles -- 1,000 hp of engine horsepower per axle -- but I think part of the secret of very high tractive effort on an AC-motored locomotive is that different axles can draw different currents (so, roughly, the one's with the best instantaneous adhesion are putting out more power than the ones going over grease spots on the rail), so the motors should have at least a short-time rating significantly above that.
The PC32acdm may not have the same traction motors as the AC60 (McDonnell's book says the P32acdm has GEB15 motors as opposed to the GEB13 on GE's domestic AC freighters), so this may be comparing apples and oranges. But if Dutch (who works for Metro-North) says the electricals of a P32acdm are massively over-designed and that they can operate at 2,800 hp with two motors cut out, I'm prepared to believe him!

(Comparison: Pennsylvania Railroad's P5a, R1 and DD-2 electric locomotives had 1,250 hp per powered axle, and could, I think, operate at a significant overload for short periods.)

Very true. hadn't really considered the short time rating, i was thinking more in terms of a continuous rating...

DC motors have a short time rating, AC motors run at almost constant current but the freqency is controlled.
A DC motor will cook itself to death, the AC motor properly ventilated by traction motor blowers is just as much at ease stopped with full power or running at maximum speed with full power.
The limits for DC traction motors is around 1200 hp, the AC traction motors have been ok at HP ratings of 2200 hp per motor.

Thanks, Dutch! I had no idea that they could go up to 2200 hp safely. ... I suppose the motor suspension standard on U.S. diesels isn't what you want for very high speeds, but that's getting up into the ratings of modern 4-axle passenger electric locomotives!

Allen Hazen wrote:Thanks, Dutch! I had no idea that they could go up to 2200 hp safely. ... I suppose the motor suspension standard on U.S. diesels isn't what you want for very high speeds, but that's getting up into the ratings of modern 4-axle passenger electric locomotives!

they have electrics over seas with motor ratings of 1600 kW (2144 hp...) so i'm not surprised.

Don't forget a AC motor trows overboard all conventional thinking.
On DC motor max power is determined by max magnetic saturation rate of the Armature and stator, the Armature is heavy and can easely bid nest as windings fly out.
only way to raise HP is to supersize the motor but there is only so much room in a truck.

An AC motor has a very light armature (squirl cage) with a small auxiliary field) its almost impossible to bird nest such a motor, all power goes to the stator (non Movable coils) so no carbon brushes or commutators.
in AC motors the Magnetic saturation is not how magnetic the core can get, but how fast can it flip its polarization.

Allen Hazen wrote:Fan Railer--
GE's AC60 freight locomotive is 6,000 hp on six axles -- 1,000 hp of engine horsepower per axle -- but I think part of the secret of very high tractive effort on an AC-motored locomotive is that different axles can draw different currents (so, roughly, the one's with the best instantaneous adhesion are putting out more power than the ones going over grease spots on the rail), so the motors should have at least a short-time rating significantly above that.
The PC32acdm may not have the same traction motors as the AC60 (McDonnell's book says the P32acdm has GEB15 motors as opposed to the GEB13 on GE's domestic AC freighters), so this may be comparing apples and oranges. But if Dutch (who works for Metro-North) says the electricals of a P32acdm are massively over-designed and that they can operate at 2,800 hp with two motors cut out, I'm prepared to believe him!

(Comparison: Pennsylvania Railroad's P5a, R1 and DD-2 electric locomotives had 1,250 hp per powered axle, and could, I think, operate at a significant overload for short periods.)

Note also that the ES44C4 units BNSF is operating are rated at 4400 HP into 4 traction motors (they have A-1-A trucks) so 1100HP per motor is doable...

From Ash Katti -- I just posted a note on the design of the GEB15 motor used on passenger locomotives, and explained why it appears over-sized when ventilated by cold ambient air but not when it is ventilated by hot air. I would like to add here a post-script that, in order to determine the GEB15's maximum rating when cold ambient air is used for cooling purposes, I ran tests simulating the freight locomotive's requirement (1000 Traction HP for each of its 6 motors), and found that the GEB15 motor could easily deliver the required output with a slight change to the turns count of the stator winding. It would, however, have a smaller sustained overload capacity compared to its much bigger sister, the GEB13, so where weight and not overload capacity is of prime concern, the modified GEB15 would be a good choice. The modification to the turns count is a trivial operation for the manufacturing dept. This is, of course, my opinion.

It's been three years in the making, but the first MPI HSP46 has left Boise.

From Sean Graham-White at the LocoNotes Yahoo Group, reposted with permission:

Sean Graham-White wrote:From: Sean Graham-White
Subject: [LocoNotes] First HSP-46 released
Date: July 11, 2013 1:57:21 PM EDT


MPI in Boise released the first MBTA HSP-46 this week. The unit is traveling UP to NS to go to GE at Erie, PA for emissions testing and then it will go back to Boise. Reporting marks for shipment should be MPEX 2000. Note that MPI is referring to this unit as a 'prototype test unit'.

I do not know how the unit is painted or if it is tarped.

Sean Graham-White

There was an article back in the middle of June about the Pilot Units:

http://bostontoat.blogspot.com/2013/06/ ... order.html" onclick="window.open(this.href);return false;

The original order of 20 was also expanded twice for a grand total of 40:

http://bostontoat.blogspot.com/2013/06/ ... track.html" onclick="window.open(this.href);return false;

And lastly, a link to the funky purple paint scheme selected by the public:

http://twitpic.com/5w6a02" onclick="window.open(this.href);return false;

a picture is posted in MBTA forum

Here is the first daylight photo of the prototype test unit #2000. She still looks pretty funky, but this shot provides a much better look at the various details than the previous nighttime shot... and the good news is that a proper paint job can only improve the situation...

Photo from ogaugerr.com

Photo by Bill Cronenberg: http://hostthenpost.com/uploads/055eaf8 ... 6a30fe.jpg" onclick="window.open(this.href);return false;

Cross-posted from the MBTA forum:

diburning wrote:Railway Age has published a spec sheet on the locomotive

http://www.railwayage.com/index.php/mec ... ormer.html

So it's 15' 4.5" high or a full foot too tall to clear New York City clearances. I haven't been inside one (yet) but I'm guessing this is not a truss bridge design body.

I think the height is wrong, the units are suppose to same height as Genesis at 14'6"