Electric Drive Tractors!!!

[CarterKraft]

The D7G II is very much old fashined.

It has the cross shaft bevel gear arrangment that is a much pain in the rear to work on. That is for the third world countries were the have to have "gear to gear" technology.

I really want to see what the back of the blade looks like, cylinder attachment points etc.

It might actually make the blade stronger due to a large triangulated mounted that spans accross the back of the blade.

After thinking about this thing while driving I am not reall sure it's abad thing. the two cylinders really didn't do much before because they are plumbed together so the blade can tilt. Now the single cylinder will remain constant while the blade tilts.
Just my .02 of course.

 

[bobcat ron]

How would a person angle the blade if there is only 1 cylinder, what I mean is if you are dozerin' along and you need to level your self off on one side to keep the machine level?

 

[Renfroe Grading]

If you mean tilt the blade the tilt cylinder will handle this. It is no different than single cylinder Terex's of the past.

 

[Construct'O]

Like posted before if your working in heavy clearing operation the single cylinder is always out front getting scraped on plus the hose assemblys to the cylinder,getting cut or pulled by passing trees limb.

Then that times when that big boulder rolls over the top of the blade right over on to the cylinder ram.It bad enough with the other cylinders and they are set back a little more at least..

The old Euclid single cylinder always got loose and sloppy in the linkage.The two cylinder help support the outside supports of the blade,especially when doing a lot of prying with the blade tilted ,cornering into hard material.

Just go find yourself and old Terex or Euclid with the single cylinder and run it for a couple hours and you will see how sloppy they are!!!!!!!!

As far as the outside plantary finals all the low drive machine are using them.

Also far as high drive repair work ,easy of them i'm with Craftman.No messing around with the old roller frames,cross shaft bearing,pressing the sprocket on and off,plus the interseals always leaking because the dead axiles coming lose in the bores case,then having to rebore housing where the dead axile fitted.

Lots of other reason i like the high track machine to the old low drive machines ,but this is just a few.

Cat please put two lift cylinder back on the machine,i'm willing to pay the extra.

It's like when they came out with high tracks and never had the carrier roller for the tracks ,now most all them have them.Because of the tracks flopping when you did a highspeed turn.Just shows none or one isn't enough when you talking dirt moving machine this isn't no skid steer,you know!:usa

 

[OzDozer]

This is what gets me most about this new tractor. For decades, Cat (and fitters) have raved on about the advantages of simple dis-assembly and minimum downtime with the hightrack design.

Now .. Cat promptly produce, a "new technology" machine .. with an undercarriage that contains all that they sneered at in the past .. low mounted, planetary finals, that are prone to damage, due to bouncing hard on them, coming back over obstructions .. poor ride of the oval track design .. a pivot shaft mounted forward of the final, with all its attendant hassles of bushings that wear, and that misalign the trackframes ..

Am I missing something here?? .. or has Cat been spinning a huge line of BS about the advantages of hightrack design??
I've never owned a hightrack, I don't particularly like the design .. and the word is, always, that high track undercarriage rebuilds, cost enough, to make any accountant with a generous chequebook, blanch .. like AU$70,000 for the last undercarriage rebuild on one of my nephews D9L's ..

Hopefully, a lot more info will come back from Conexpo to enable us to get a better handle on what Cat have done here .. but at first appearances, it largely appears to be a number of steps backwards .. at the same time as they've taken a couple of steps forwards .. but, hey .. that always appeared to be the case, when hightracks were first presented to us, anyway ..

 

[activeorpassive]

And to top it all .. the whisper is, that the AC drive technology for the D7E, has merely been purchased from an off-the-shelf supplier ..

I don't know of any manufacturer that produces an "off-the-shelf" electrical system for tractors. I don't know if CAT is using suppliers for components, but I'm sure they would as CAT is not in the business of making electric motors. Yet. Parts may have been spec'd out and produced by vendors, but the system is definitely not "off-the-shelf." Off the shelf would have to refer to an electric drive system. If there's an AC system out there that already exists then it would be on another tractor.

If Cat have done this right, the tractor may be a winner. The simple fact of the matter is, that diesel electric drive is a very efficient method of propulsion .. and R.G. LeTourneau was 50-80 years ahead of his time, when he produced an electric powered scraper in 1922 .. produced the AC "Tournatorque" electric motor in 1948 (that could operate under water and produce maximum torque in 1/6th second) .. and patented the electric wheel motor in 1950.

Again, the old electric systems were DC powered, which, although cheaper to build initially, required more maintenance and are less reliable. As I have posted in another thread, DC is seeing a rapid decline as AC technology is becoming less expensive to develop and implement. This is the first tractor of it's kind--AC.

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?

CAT is using the SystemOne undercarriage for the oval-track. I feel one of the main reasons for going oval-track on this machine is due to the incorporation of the SystemOne undercarriage. If the SystemOne is all it is claimed to be, then the benefits of the SystemOne undercarriage should negate any need for an elevated sprocket design on this size of a machine. More details on the SystemOne can be found at:
http://www.cat.com/cda/components/fullArticle?m=48863&x=7&id=313170

The water pump isn't gear driven. It is an electric pump that will be powered by the electrical system.

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?? ..

I don't believe it is any different than if your starter or alternator is faulty. Most heavy equipment customers or shops don't have the tooling or experience to rewind these components. It's more feasible to buy new or remanufactured. Will one be able to send a motor to a rewind shop? I can't say for sure. A customer would have to weigh the difference between tearing apart the propulsion module to gain access to the motors for rewinding vs buying a new or remanufactured propulsion module.

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 ..

The motors will be liquid cooled. There is an auxiliary cooling system that will use jacket water to cool the Power Converter and the electric motors (there are two of them).

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.

There are two motors that supply the input to the differential system. There isn't a motor on each side of the tractor, but two motors contained within the propulsion module. The diff steer will still work off of hydraulics.

I agree with a lot of people on this thread. This will be a great system. If it works. From what I've heard, this thing pushes like a D8. There's gobs of torque due to the AC motors being able to produce full torque at nearly zero RPMs. I feel CAT has really laid it out there, and a lot is at stake. If it fails, then everyone can say "I knew this was a bad idea," but at least it'll fail on a platform that is CAT's weakest seller. If the system is what it's being hyped to be, then competitors are going to be scrambling, and the D7 may just become number one in the sales logs.

 

[Northart]

One Post Cab ?

Hello Active or passive,

Got a ? about the One post cab or ROPS ?

I've never seen anything wrong with the current cabs, far as visibility !

I like to have the doors open, when practical, to get real freah air, and hear, smell, the sounds of work !

Stuffy cabs puts guy to sleep like, dulls the senses. Screw that air conditioning. I hate it , creates rhuematism in my shoulders.

The drawbacks of the new D7E is the "Glass Doors" . Extremely vulnerable over time !

And it allows all the dust and dirt to enter the cab if open. Where are you going to get a replacement, broken in the field. The steel framed windows and doors , any glass place local, could fit you with a replacement in short order. Got to buy the whole 9 yards , hinge, door latch, seal, etc. Nuts ! EXPENSIVE !

Not good all this glass stuff ! Its a industry prevalent problem, far as replacement cost !

Just some feedback .

 

[alco]

I guess we'll finally get the D8's we've been asking for or a different brand since I honestly don't believe that these electric drives will work for us. Yes, I know they claim the electric drives are sealed, but the slop we work in is very corrosive and eats the seals out of everything as it is. I just can't see the seals lasting very long until the sand and water get in and destroy it. Everything gets full of sand and covered by it as well.

Oh well, if we go to a different machine, I guess we'll be able to get away from differential steering too as an added bonus.

Brian

 

[AtlasRob]

new tec

Well thats caused some intresting debate New technology or old technology in a different package ?
High drive, low drive, :beatsme. Throughout history mankind has pushed the boundarys of technology and sometimes got severly burnt, well a big bit of egg on the face anyway.
Humble pie can be a bit chewy after a while so I will just say, at least C@t haven't sat back and said everything about our machines is perfect, we dont need to look at changing anything. :stirthepot

The oval track 6K got a brief mention in passing, there is one on the job I am on it looks to perform very well though I do know it has a heater prob, I believe C@t are going to replace the matrix.

 

[Ray Welsh]

Well thats caused some intresting debate New technology or old technology in a different package ?
High drive, low drive, :beatsme. Throughout history mankind has pushed the boundarys of technology and sometimes got severly burnt, well a big bit of egg on the face anyway.
Humble pie can be a bit chewy after a while so I will just say, at least C@t haven't sat back and said everything about our machines is perfect, we dont need to look at changing anything. :stirthepot

The oval track 6K got a brief mention in passing, there is one on the job I am on it looks to perform very well though I do know it has a heater prob, I believe C@t are going to replace the matrix.

Here's my .02cents worth. For those who doubt the torque of electric drives, please Google "Electric Wheel" or "Soloman technoligies" section. These were made to operate for marine engine propulsion and I doubt if there is a more hostile environment to electrics than sea water.
As for negative comments on the single blade ram, it served quite well on terex bulldozers and indeed all cable blade machines including Cats, with zero adverse effects on blade life or control.
To the bloke who objects to the windows and air-conditioning, the volume of clean air should be fully adjustable for temperature just like all past machines. Personally I would not drive a car, truck or any machine without windows and intigrated climate control.........C ya..........Ray

 

[OzDozer]

Again, the old electric systems were DC powered, which, although cheaper to build initially, required more maintenance and are less reliable. As I have posted in another thread, DC is seeing a rapid decline as AC technology is becoming less expensive to develop and implement. This is the first tractor of it's kind--AC.

FYI - LeTourneau designed, patented and produced, a 120V AC motor in 1948, called the TournaTorque motor - to specifically operate the cable control winches and the electric steering on Tournapulls. This electric motor stunned the industry, and physics professors, alike, when LeTourneau built it .. as it was reputed to be impossible to build.

This motor was capable of producing full power in 1/6th of second, were extremely rugged in operation .. and produced the operating characteristics and lugging ability of a series wound DC motor.
To demonstrate the ruggedness and to show that the TournaTorque motor was unaffected by water or dirt .. LeTourneau put on a display at the 1948 Road Show in Chicago .. of a TournaTorque electric motor, submerged (and operating) in a drum of water.
This motor remained submerged for two years .. and it was regularly operated at intervals, to show that it was still continuing to operate perfectly, despite the lengthy submersion.

Surprisingly, when LeTourneau produced his electric wheel, it WAS driven by a DC motor. Why he never used the TournaTourque motor in his electric wheel, is beyond my understanding, but maybe he was going to .. but the Westinghouse buyout threw a wrench in his plans.
Not surprisingly, the current line of LeTourneau wheel loaders uses AC drive motors in their propulsion system .. and probably 90% of current LeTourneau technology is based on the pioneering electrical work done by R.G.
The only thing that has changed since R.G.'s time, is electronics, and microprocessors that now offer superb control of the otherwise difficult-to-control AC motors.
The electrical power system development, that R.G. achieved .. at at time when even the transistor had only just been developed (and the Americans didn't know what to do with that - so they sold it to the Japs!) .. is nothing short of incredible.

I don't know of any manufacturer that produces an "off-the-shelf" electrical system for tractors. I don't know if CAT is using suppliers for components, but I'm sure they would as CAT is not in the business of making electric motors. Yet. Parts may have been spec'd out and produced by vendors, but the system is definitely not "off-the-shelf." Off the shelf would have to refer to an electric drive system. If there's an AC system out there that already exists then it would be on another tractor.

Well, I guess we could get picky here, and agree that there's no other current crawler TRACTOR with an electric drive system. However, there are three companies that can supply you with an electric propulsion system for your new design, off the shelf. They are Siemens, GE and LeTourneau. Another nephew is currently building six, electric drive, dump trucks of his own radical design .. and those three companies offered to supply the propulsion systems.

 

[CEwriter]

Hello Active or passive,

Got a ? about the One post cab or ROPS ?

I've never seen anything wrong with the current cabs, far as visibility !

I like to have the doors open, when practical, to get real freah air, and hear, smell, the sounds of work !

Stuffy cabs puts guy to sleep like, dulls the senses. Screw that air conditioning. I hate it , creates rhuematism in my shoulders.

The drawbacks of the new D7E is the "Glass Doors" . Extremely vulnerable over time !

And it allows all the dust and dirt to enter the cab if open. Where are you going to get a replacement, broken in the field. The steel framed windows and doors , any glass place local, could fit you with a replacement in short order. Got to buy the whole 9 yards , hinge, door latch, seal, etc. Nuts ! EXPENSIVE !

Not good all this glass stuff ! Its a industry prevalent problem, far as replacement cost !

Just some feedback .

What's your question? What kind of feedback are you looking for?

L

 

[Northart]

Cab

Hello CE Writer,

Perhaps I rambled on too much without clearly stating my question.

I see "Glass " becoming more than a window to look through. It's becoming a structural component. Now we are seeing more complex curved planes, with irregular outlines , with the hardware attached to it. I.E. Door handles, windshield wipers, antennaes, heater elements.



I'm looking at it from another point. Durability and replacement. Glass damage from flying rock,road gravels, demolition work, land clearing,vandalism, etc. No longer is a simple matter of pulling a rubber gasket out, and popping a new window in. Replacing glass nowadays , has some to be Glued in and cured, creating machine downtime. And securing a replacement takes time also.

Are these glass components going to be available 10-20 years down the road ?

Why is the trend going this way, vs , steel frames with plate glass, and rubber gaskets ?

The " one post " cab ? Is this a one post in the middle to support a canopy for ROPS and FOPS protection? No longer the post on each side.

 

[bolt thrower]

Here's my theory on the reasoning behind this Electric drive system; Caterpillar is thinking ahead. This D7E is a platform just waiting to have a Hydrogen Fuel Cell dropped in place of the C-9 + Generator unit. A fuel cell converts the chemical energy in hydrogen directly to electricity without the pistons, crankshaft, etc. And the machine is already configured to accept it, right down to the electric air conditioner unit! Just think of how few parts there would be to wear out without a diesel powerplant, not to mention 0 emissions. This is what its coming to Guys.

 

[AtlasRob]

wow

Here's my theory on the reasoning behind this Electric drive system; Caterpillar is thinking ahead. This D7E is a platform just waiting to have a Hydrogen Fuel Cell dropped in place of the C-9 + Generator unit. A fuel cell converts the chemical energy in hydrogen directly to electricity without the pistons, crankshaft, etc. And the machine is already configured to accept it, right down to the electric air conditioner unit! Just think of how few parts there would be to wear out without a diesel powerplant, not to mention 0 emissions. This is what its coming to Guys.

WOW! Bolt thrower, you should be called 'spanner thrower' with that one landing in the pot :notworthy

 

[Ray Welsh]

Here's my theory on the reasoning behind this Electric drive system; Caterpillar is thinking ahead. This D7E is a platform just waiting to have a Hydrogen Fuel Cell dropped in place of the C-9 + Generator unit. A fuel cell converts the chemical energy in hydrogen directly to electricity without the pistons, crankshaft, etc. And the machine is already configured to accept it, right down to the electric air conditioner unit! Just think of how few parts there would be to wear out without a diesel powerplant, not to mention 0 emissions. This is what its coming to Guys.

Hey Bolt thrower, You might be right on the money there. In fact, if the oil price stays high many more manufacturers will join this positive move.
Peak oil might do us all a favour to assist in reducing Co2 emissions.......C ya......Ray

 

[CarterKraft]

I like the Hydrogen fuel cell idea but I think we are light years away from getting off oil.

A major advantage in my mind is the steady state engine you will now have. No low RPM acceleration emmissions that are so hard to get rid of, not to mention the increased efficiency, the amount of heat a non lockup torque converter makes is incredible.

I will also bet that the glass in the cab doors is like the new K series, Not glass but Lexan/PLexiglass makeup. As to all your other questions on availabillity and structure, I don't know and have'nt really put much thought in it. To be honest I prefer the glue in type myself.

 

[Ray Welsh]

I like the Hydrogen fuel cell idea but I think we are light years away from getting off oil.

A major advantage in my mind is the steady state engine you will now have. No low RPM acceleration emmissions that are so hard to get rid of, not to mention the increased efficiency, the amount of heat a non lockup torque converter makes is incredible.

I will also bet that the glass in the cab doors is like the new K series, Not glass but Lexan/PLexiglass makeup. As to all your other questions on availabillity and structure, I don't know and have'nt really put much thought in it. To be honest I prefer the glue in type myself.

Hey Cartercraft,
Hydrogen fuel cells are more common than you think and can replace oil just as soon as major investors come onboard. The waste products to the atmosphere are water and Oxygen. Then the remaining oil can be used for lubrication of heavy gear assemblies.

Heat generating torque converters could be used but are not a necessity with electric drives. Google "solomanindustries.com" and search for their drives.
To me they look like an infinitely variable system or maybe I'm confused,
Again?????.........C ya.........Ray

 

[alco]

Hey Cartercraft,
Hydrogen fuel cells are more common than you think and can replace oil just as soon as major investors come onboard. The waste products to the atmosphere are water and Oxygen. Then the remaining oil can be used for lubrication of heavy gear assemblies.

Fuel cells are becoming more and more common, but I believe there is a ways to go before they will perform reliably when you beat them around on a piece of heavy equipment. If they can get the cost down and make them tough enough, I think there is a great deal of merit to the idea of using them instead of internal combustion.

Brian

 

[CarterKraft]

Hey Cartercraft,
Hydrogen fuel cells are more common than you think and can replace oil just as soon as major investors come onboard. The waste products to the atmosphere are water and Oxygen. Then the remaining oil can be used for lubrication of heavy gear assemblies.

Heat generating torque converters could be used but are not a necessity with electric drives. Google "solomanindustries.com" and search for their drives.
To me they look like an infinitely variable system or maybe I'm confused,
Again?????.........C ya.........Ray

I don't doubt the practicallity of fuel cells but we are along way from them guys, really.

Yeh I was stating the amount of energy wasted in a torque converter kills efficiency, and other things.

I can't wait for hybrid tractors, fuel cells and whatever technology they can throw at these machines. I love gadgets and anything people are scared of, so a diesel electric dozer is awesome.