EMD SD70ACe series official thread (covers all variations)

[ATK]

The Mitsubishi inverter system utilizes IGBT technology.

As info, GE has not used GTO's in production of freight locomotives for many years now. I don't recall exactly when production was cut over from GTO to IGBT, but I would hazard a guess that its easily been 6 years now. For passenger locomotives, the story is a little different. The last batch of P32ACDM locomotives built for Metro North in 2001 are equipped with GTO's. The reason for this was that there would have been far too great of an expense for GE to redesign the inverter system and packaging of the locomotive to accommodate the IGBT's. That, plus it would have meant that Metro North would have to stock additional parts. Too bad too, because the IGBT's are far more reliable than the GTO's.

[Justin B]

Pardon the ignorance...

But what exactly are are GTOs and IGBT's?? And how are they different?

Thnx.

[Allen Hazen]

I can't remember when GE switched from GTO to IGBT (an appoximate date was given by someone in a post to the GE forum, probably the OLD forum), but there is an external spotting feature: the top box on the left side behind the cab housing the invertors is a few inhes lower on newer AC44 than on the first ones built: I think this corresponds to the change in invertor type IN the box.

[ATK]

Justin - rather than me make a feeble attempt at trying to explain IGBT's and GTO's, I recommend that you do some research on the internet. A quick Google search turned up this link on some basics on IGBT's:

http://www.elec.gla.ac.uk/groups/dev_mo ... /igbt.html

Allen - you certainly pay very close attention to detail! I never looked that closely at the height of the inverter box on the left hand side of the aux cab. Although I don't know for sure, I would have to disagree and say that they are probably the same height, and my reason for saying this is that a smaller inverter box to accommodate the IGBT's would have meant that GE did some redesign work of the packaging of the aux cab -- work that they are not very likely to do. The IGBT's certainly do take up less space inside the aux cab than the GTO's, but despite this GE was (is) not likely to reduce the size of that compartment. In other words, if the existing design works, go with it. From what I can remember in regards to external spotting differences between a GTO unit and an IGBT unit is the vertical sheet steel on the outside of the inverter box. The GTO units has six distinct bolted on panels on the outside of the box. The IGBT units has two (or maybe three?) distinct bolted on panels. I believe this was due to the arrangement of the filter capacitors inside of the aux cab.

Say, aren't we getting off topic here? This is the EMD forum...

[Justin B]

Thanks for the link

Why didn't I think of doing that myself....?

[Jamshid]

GE has not used GTO's in production of freight locomotives for many years now.

Sorry,You are right, GE has switched to IGBT.

Unfortuately, there is no info concerning inverters in GE sepec sheets that was caused my mistake.

But what exactly are are GTOs and IGBT's?? And how are they different?

In comparison IGBT based inverters are cheaper, smaller, more reliable and more efficient but need more complicated control system to control them.
(With new technology, GTO inverters won't have any justificaton to be used any more and I predict that within a resonable time all locomotives which have GTO inverters will be retrofited with IGBT ones.)

This thread has brought about more questions, in addition to traction motor type:
1. Do SD70ACe locomotives have per axle( 6 inverters) or per truck (2 inverters) traction inverters?
2. Which cooling method has been used for inverters?
3. What type of control system and from which manufacturer has been used to control the inverters?




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Trivial P.S. Mitsubishi was the manufacturer of A6M Zero Fighters which destroyed pearl harbor in WWII.

[Allen Hazen]

From another page ("technology" link on the "locomotive models" page) of the GETS WWWebsite (reference to CP interesting: I think the first AC44 order with IGBT may have been a CP or a UP one; I've noticed the change in invertor-box sheet-metal between photos of CP's first AC44 and later orders):
The GE AC Traction Control System features exclusive single-axle wheel slip control, made possible by the full utilization of single-axle inverter control.
Introduction of the system is the culmination of years of AC propulsion experience as well as an intense three years of work with Canadian Pacific Railroad in some of the toughest heavy-haul applications in the world.

The key component of the inverter package is Insulated Gate Bipolar Transistor (IGBT) technology. The IGBT offers advantages in terms of reliability, packaging and robustness over the previous Gate Turn-Off Thyristor (GTO) design. With more than 5,000 fewer components, it's easy to imagine-just on the basis of raw part count-how IGBTs take up less space, weigh less and are more reliable. GE Transportation Systems has designed and thoroughly tested these air-cooled units using rigorous Six Sigma practices to ensure the highest reliability.

The GEB AC traction motor delivers proven AC propulsion. This low-slip motor offers higher efficiencies and the reliability of a one million-mile overhaul cycle. The GEB motor also has an integral pinion design and can produce full torque independent of wheel size.

The traction control system utilizes IGBT technology, the GEB AC traction motor and single axle inverters to create a system that delivers the greatest adhesion, highest reliability and biggest efficiencies available today for heavy-haul applications.

[Jay Potter]

The SD70ACe has model A3432 traction motors and one IGBT inverter per truck.

[Jamshid]

The SD70ACe has model A3432 traction motors.

Thanks Jay,
Manufacturer name please?

[Jay Potter]

Mitsubishi

[Jamshid]

Thanks again,
It seems that EMD has taken secrecy policy over Mitsubishi role in SD70ACe.

I've finally found that EM2000 conrol system has been remaind intact in SD70ACe locomotives:

The SD70ACe’s electrical system configuration is where the changes are not so subtle. Just behind the cab, a large electrical locker that accommodates two service technicians centralizes all major locomotive electronics: EM2000 control system, a.c. traction inverters, contractors and switchgear, and feedback devices. The a.c. traction system’s inverter controls are integral with the EM2000 system.

In MAC versions, there is an elecronic card in EM2000 to communicate with quite independent traction and brake control systems.
One of vulneabilities of MACs was excessive hardwares to control locomotive.
A Siemens SIBAS32 control system module would be sufficient for all control tasks but EMD insisted on its EM2000 and prefered to use two Sibas16 inferior modules for traction control in MAC locomotives. (I don't know the scenario with Mitsubishi)

[Nasadowsk]

Interesting that GM picked up Mitsubishi for their inverters now. Though Mitsubishi doesn't make locomotives for the international market, AFAIK. Siemens does, and I suspect a break from Siemens will mean EMD becomes a minor player in Europe, esp if Siemens has a competing product, which will likely be taylored to European prefs anyway (i.e., quieter/cleaner prime mover, fully suspended motors, dual cabs, etc)

GTO is a derivative of the SCR, I think, but allows one to turn off the device at will. I believe they had a number of design features that make them less desireable than IGBTs, but they were initially better than IGBTs and MOSFETs at handling higher power levels. Quite a few recently delivered electric locomotives are GTO, though, since IGBTs are still a developing (though close to mature at this point) technology. Remember that electrics are not only much higher power than diesels, but have a much more robust supply behind them. ABB, etc talk of 'explosion resistance' in packaging - i.e. the ability to not blow up like an M-80 when they fail.

I'm not sure of the development history of IGBTs and where they came from. AFAIK, they're not really FETs, but they're not SCRs either.

[jesse corbett]

With regards to BASIC HV peration, the SD70ACe is a copycat of the SD70MAC except the change to Melco (Mitsubishi Electric Co.). Melco does the inverters and EMD/ Melco/ and other third parties do the traction motors although EMD will handle all sales, service and parts exclusively.

Siemens uses gate drivers, Melco uses IGBT's. The Melco units are smaller, much faster, and 10 times simpler and easy to get too than the Siemens systems partially due to fiber optics instead of wires. The phase modules are still much bigger than GE (due to truck control versus individual motor control) but they are "slide in/slide out" units can be changed out quickly.

EMD and Siemens are no longer in an active partnership for new technology although their is still support for all the MAC's. This falling out wont have any effect on European sales/service for EMD as Siemens never was in a "controlling" position anyway. The only thing it may hurt is someones feelings in Germany.

[trainiac]

Just found out that KCS has ordered 30 SD70ACe's to be delivered in the fourth quarter of 2005. Apparently the demonstrators performed well.

http://www.progressiverailroading.com/f ... sp?id=6194

[MEC407]

One of the things I noticed in that press release when I first read it a couple days ago was this quote:

"The primary benefit of the SD70ACe is that it can pull 9.6 percent more 110-ton coal cars than any of the locomotives currently in [our] fleet," KCS officials said in a prepared statement.

So... apparently an SD70ACe can pull a few more loads than an AC4400. That is interesting and a bit surprising. I wonder how the SD70ACe would compare to an ES44AC under the same circumstances.