Electric Drive Tractors!!!

[CarterKraft]

Well if you look at the low drive from a mechanical drivetrain point of view, it is junk and outdated. If it is hydrastat or electric drive then ?

Cross shaft, spur pinions etc are all costly repairs and are not good for production machines. You can have the trans/diff and finals swapped before you can get a old cross shaft drivetrain torn down.

I bet the DPF/ Catalyst for Tier 4 is gonna be a monster, and will require a ton of room to keep it heat shielded etc.

So is the water pump gear driven off of the front gear train or the rear?
Haven't seen a gear drive C9 water pump yet?

 

[9420pullpan]

Now that is what makes Cat such a great company! i love these great ideas of these new machines. i mean look what has been introduced since the last Con-Expo in 2005 the M-Series grader, the D6K great size, the 657G update, the new 345D coming out the 953-973D's. the list goes on and on. I can not wait to get to Vegas to be around many other people like myself who have such a passion for this industry!!

I look forward to seeing everyone there.

 

[VjjR]

look at train engines... they been diesel generated electric for how long now. talk about torque

 

[EquipmentEditor]

CEwriter's video has been posted.
http://www.constructionequipment.com/index.asp?layout=videositeTOC

 

[Countryboy]

Welcome to Heavy Equipment Forums Accertin! :drinkup

 

[stuvecorp]

Thank you Construction Equipment:notworthy I think it has been exciting to see this new type technology, even if it is 'recycled' and it will further every brand in the end.

 

[CEwriter]

the D6K great size,

Speaking of the D6K, what would y'all think about a D6 with oval track, ie: no elevated sprocket?

Allow me to paraphrase the Cat line on the D7E's oval track. 'We studied all potential applications of the D7E, and decided that oval track was the best way to go. The greatest advantage of elevated sprocket design comes with suspended undercarriage (oscillating bogey wheels). Only the D8 and larger sized tractors have suspended undercarriage. D8 and larger sized tractors will continue to be offered as elevated sprocket tractors. We will continue to evaluate the undercarriage designs of D7 and smaller tractors.'

Oh, and the D7E is going to replace the D7R. Probably not right away, but Cat will taper off production of the D7R in favor of the D7E.

Hmmm,

L

PS: Don't miss the D7E video with narration by Cat's own John Walker. http://www.constructionequipment.com/index.asp?layout=videositeTOC

 

[OzDozer]

What stuns me about this thing .. is that it uses an undercarriage that is a dead-ringer for the TD15 planetary-style undercarriage .. and Cat sneered at the TD15 design as being a dead loss for strength, reliability, track misalignment under track frame oscillation, and the amount of components required .. as compared to Cat tractors of the day ..

Now .. magically, this 'outdated', 'inadequate', 'inferior' system of IHC's .. suddenly becomes the answer to every crawler tractor owners prayer .. in 2008 ..

Methinks this is a triumph of marketing BS, over engineering ..

The other factor is .. just how repairable are these electrics gonna be? Is it a case of an owner being able to rebuild them at the local rewind shop? .. or will they NEED to be sent back to Cat for exchange .. with "repairer/user safety issues", being stated as the reason we can't repair them on our own turf?? ..

The last and most interesting feature has to be cooling. We always operate Cats in 40-50°C + temps in Australia .. and they have always run hot, regardless of the model/jobsite/conditions .. and .. electric motors generate a LOT of heat (I can recall smoking a few D-Pull lift motors .. ) .. so .. I wonder just what the cooling setup is, on these things?

Those motors buried in the frame are gonna need a LOT of cooling air .. particularly when they are loaded up and grunting all day long .. I trust the engineers have done their homework ..

 

[bigfoot]

It seems to me as if it only has 1 drive motor that replaces the converter and trans, still has diff steer. I would have thought that a motor in each side would be a better set up.
Also did you see that ripper on the video, looks like they took it of a Komatsu.
But a very interesting tractor indeed and Good luck to CAT.

 

[CEwriter]

Cat chose to use a lower-voltage drive system to eliminate the need for a cetified electrician to work on them - to make them more serviceable in the field.

The cooling fan is hydraulically driven, on demand.

The motors are liquid cooled.

I think they upsized the radiator, but I'll need to confirm with the product guys when I see them later this week. I'll let you know.

The marketing lingo is that "We've designed the machine to work everywhere a D7R works." And as they plan to replace the D7R with it, seems like it would be commercial suicide to spend all the R&D money developing the drive system and then fail to make sure the thing is, indeed, capable of replacing the 7R even in high ambients.

L

 

[Countryboy]

Welcome to Heavy Equipment Forums bigfoot! :drinkup

 

[bobcat ron]

AC motors don't develop as much heat as the DC ones do, but there might be a water jacket around the the motor that is part of the engine cooling system.

 

[Scott_527]

Is it just me or does Deere suddenly seem like a lot better choice?

 

[d4c24a]

new technology

Is it just me or does Deere suddenly seem like a lot better choice?

NO dont knock it until you try it you may end up looking silly you may not

 

[d6peg]

I would like to give one a try sometime, but it sure seems to me that you ( the O/O ) will no longer be able to work on your own machines like in the good old days.

 

[Northart]

CE Writer ?

Hello CE Writer,

The D6K ? I personally like that size machine.
I like the joystick steering feature. Thumbwheel on the dozer angling. Have not, got to run one, so I can't express further thoughts.

The D6R is really like an older D7. Getting too big for its class or size.

Like the L series dozers. Got too big for the size or class, then was downsized to the N series.

The PAT dozer I was wanting for years on that size machine. For cleanup and finishing work. I know the D6N, D6M got it.

As for small or midsized dozers , the Hi sprocket ones are heavier. Not what you want some days. Depending on the work. Mechanics I think prefer the Hi sprocket models for ease of working on.

How did they come up with the designation of Cat D7E ?

Does "E" stand for Electric ?

My thoughts anyway.

 

[dhjmdls]

OK, OK...here's some info.

Settle down, everyone, it's only the largest collection of improvements to a dozer ever made at one time, by any manufacturer.

OK, it's a 235hp C-9 ACERT (Tier3) engine tied to a generator (in place of the traditional torque converter), which powers a two-motor "propulsion module" through a trio of fully sealed & protected cables. Power is then transferred out to the final drives through a set of short "axle shafts", which are inboard on the main frame.

All-electric HVAC system (no belt-driven compressor), converter (instead of alternator), hydraulic fan, seat-mounted controls, single a-post cab (man, you don't see anything but the horizon when you look out the front of this baby) - the front cab post, exhaust stack, and single lift cylinder are all lined up! And, did I mention, this cab is friggin' huge - it's also refined and clean, not muddled up with a lot of useless techno-crap!

The cab tilts for easy service, but met a CE writer today, and he said Cat was touting something like 40-50% fewer parts to the drivetrain, so I'm not sure what all could possibly be underneath!

It's got a pretty cool "double-hinged" set of radiator doors, so you can actually get in there and clean it if you have to, without having to remove friggin' bolts.

Yeh, it's oval track, but Cat knows good and well that they didn't need to take that elevated stuff all the way down to a D4H, for cryin' out loud. Besides, if this machine isn't comin' out until 2009, I'd guess they're still gonna sell the D7R for a little while.

As for other manufacturers (of those I've seen thus far), Deere is showing some crazy "quad-trac" copy with a small blade out front (so that's what was under that tarp on their website)...not sure what it would be used for, but looks atrocious and cumbersome...maybe not a "better choice" as previously thought (by others) : )

Lots of good stuff to come, as soon as I can get my photos downloaded!

 

[Countryboy]

Welcome to Heavy Equipment Forums dhjmdls! :drinkup

 

[Hjolli]

Well well, this all sounds very good, and Cat probably isn´t bringing out this machine if it isn´t making good sense.

But from a mechanical point of view the single cylinder still puzzles me. It is bound to make app. twice the the torque load on the blade than 2 cylinders. I wonder how they stiffened the blade to make up for that. For some reason almost all manufacturers have been using 2 cylinders since the advent of hydraulics some 50 yrs ago. The old cable controlled blades must have been weaker with only a single lift in the middle.

I have been wondering why the D6T didn´t change all that much from the D6R; the d8 thru d11 all had new cabs, the D6 didn´t. A low drive electric D6 might be coming soon.

And as for the hi drive, one benefit is definitely good ground clearance and a clean bottom.
Wonder how the make up for that.

It will be interesting to see more pictures....

 

[Hjolli]

And by the way, this D7G series II isn´t so old fashioned after all then.....