Cat Electric D7

gf beranek

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http://gas2.org/2009/09/18/caterpillar-builds-worlds-first-hybrid-bulldozer/

Interesting that they dropped the high-track design.

d7e.jpg
 
High drive is an option on Cat Dozers, depending on the application. Not surprised their going over to electric drive. All other big mining equipment uses that system. Neat find Ger.
 
the writer of that article is pretty clueless. Like I said, most heavy mining equipment runs DC electric drive. Be interested to see Al's opinion on putting it in this size machine.
 
Caterpillar’s popular D6 and D8 models, and commands a price premium of 20%, or $100,000, over a standard D7R. But that 20% can be recouped in as little as two years thanks to fuel savings of 10-30%.

Green? Whatever...It comes down to cash.

Rubber meets road.
 
I always wondered why they didn't do this in trucks also. Eliminate all that shifting. My Dad has a Caterpillar RD-6, 1938 model and it has a beltless engine. Took them 80 years for it to become new again.
 
I posted a picture some time ago showing a mining machine used to carve out wine caves. Ran on electric power. Apparently they have been around for awhile but this is the first engine/electric on I've seen.
 
Very cool. I was thinking the same thing Thor, technology Cat has been familiar with for a long time on their big trucks. Had our ole' D5 running today. Gonna go somewhere and make a mess with it tomorrow, I think.:D
 
I wasn't aware that Caterpilar is going to electric drive .It makes good sense but is nothing new .The RJ LeTourno Co .[can't spell ] used it years ago with great success . It's much easier to couple the power to the tracks via a DC motor than by a mechanical connection of some sort .

You could use the example of a diesel locomotive or in my case a diesel electric submarine .Both work extremely well as a drive method .

Actually the huge 300 plus ton quarry trucks made by Cat as well as others use electric propulsion . In addition to the power transfer you also have dynamic braking because of the design of a DC motor but that's another subject all together . Another added benefit would be the massive amounts of electrical power on hand that could be used for a host of things .

Caterpilar is usually on the leading edge .I imagine old Ben Holt would be proud of them .:)
 
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Diesel electric has proved worth while in many applications, but this I have some wonders about. It appears to eliminate clutches, hydrostatic drives and transmissions. That's a plus, but what about the maintenance on those electric motors. They must have some massive torque.
 
They are geared down by the final drives but yeah, they got to have some power.
Not too many people know about Ben Holt Al. The family still owns the Cat dealership in Stockton and Los Banos. Caterpillar took quite a blow to their corporate ego when they missed the 2007 EPA emissions standards on their truck motors.
 
That's cool Ed. I've seen a few pieces of Loadall equipment around and the JCB hydraulic excavators.
 
I didn't check it out but I imagine the drive motors on that thing are servo motors. They have pretty much taken over on electric drives .

A company by the name of Indramate from I think Sweden is one of the leaders in this technoligy and I work with them on nearly a daily bassis .

Unlike the older compound wound DC motors of the past these things have infinate speed controll and operate on small solid state elecronic controllers which in this application if that is what they use would be very robust .

This company took two 80 HP servo motors and ran city busses in LA with them,battery operated had had good success .You have to remember that 80 HP electric is about 200-240 gasoline .It's somewhat confusing when compairing actual horsepower because of the way it is rated .

If that dozer has final drives that would be most likely the only maechanical link between the track and the main engine .No need for clutches,tranny,steering clutchs or any of that stuff . It would turn on a dime,Forward on one track,reverse on the other .
 
More history of the crawler .The high track design is nothing new either .It goes back to Cletrac in about 1920 . The idea is two fold .The sprocket etc is kept high out of the mud and the track action is the same in forward or reverse .

On a conventional crawler going foward you are pulling track ,reverse you are pushing .Pushing lumps up the track and just plays hell with the under carriage . Reverse is when you normally throw a track if it's going to come off .This will make a preacher cuss .In addition a high track needs no idler rollers and has about 50 percent more track thus should last about half again as long .
 
Not too many people know about Ben Holt Al. The family still owns the Cat dealership in Stockton and Los Banos.

They also had Holt /Rafakus in Toledo Ohio .It's under a different name now .

Little known fact,Holt owns two large Cat bone yards in Texas or did at one time .
 
More history of the crawler .The high track design is nothing new either .It goes back to Cletrac in about 1920 . The idea is two fold .The sprocket etc is kept high out of the mud and the track action is the same in forward or reverse .

On a conventional crawler going foward you are pulling track ,reverse you are pushing .Pushing lumps up the track and just plays hell with the under carriage . Reverse is when you normally throw a track if it's going to come off .This will make a preacher cuss .In addition a high track needs no idler rollers and has about 50 percent more track thus should last about half again as long .

Another advantage to the high sprocket was ease of removing the final drives and the tranny. They could break the track and remove the whole component out the side and I believe the tranny came out the rear, but I'm not certain. On the low sprocket tractors you broke the track, removed the seat and tank and canopy/cab. The high sprocket never really made it as an Ag tractor, mostly construction. You see a few of them on large rippers but that's about it. The Challenger series is a fantastic Ag tractor (after the first three models) and Cat sold it off a while back, I think to AGCO-Allis.
 
The high sprocket never really made it as an Ag tractor, mostly construction.

I see a few of the Quadtracs in use around me. Track replacment and undercarriage costs scare the farmers away. The ammount of road time moving from field to field is important too, asphalt is hell on ag tires, gotta believe tracks are the same.

Steiger_535QT-001-01r-540.jpg


The tracked machines really come into their own in poor ground condidtions, CaseIH even has a new combine that is tracked.

http://www.youtube.com/watch?v=ZTjdz75t8pc

Ed
 
You see a few of those around here also. They look to be like the challenger, best of both worlds. Flotation and traction of a track, and speed and the ability to run on asphalt of a tire.
 
If I'm not mistaked,Goodyear in St Marys Ohio makes those webs for the rubber tracked ag crawlers .In addition they make conveyer belting and tank tracks for the Abrams tank .

That aside I think you can get the rubber webs refurbished .They claim that in the long run those Cat challangers were actualy cheaper to operate than a big 4 wheel drive running duals all the way around .It took that much rubber tires to equal the tractive effort of the crawler tracks .Of course at the time Deere disagreed with what Cat said on the subject but a year or two later came out with their own crawler drive .That tells me something .:lol:
 
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