Electric tractor

[Steave]

I had a great experience Thanksgiving day with EV autos. I got to ride in a Tesla S P100D and that changed all my doubts about electric vehicles of ANY kind. Quiet an experience for an ole country boy as myself. I've always been intrigued with electric motors and electric autos and I could see direct drive with the 3 phase motors such as Tesla uses. The Tesla has (2) 3 phase motors, one front and one rear and is 4 wheel drive with traction control. There would be no use for a transmission of any kind using a high tech motor controller such as the Tesla. The batteries and cooling system make the Tesla heavy as mentioned by CincyFlyer 5000 + lbs. I'm not sure how they do the 4 wheel drive but would like to find out what type of differential or whatever apparatus is used.

From a dead stop you'd better push your head back into the head rest before accelerating because it is some more fast. The range doing average driving is somewhere around 300 miles on a charge. I'm not sure how that would relate to a tractor's task but at $130,000 (Tesla's price) I'll never find out. They make lesser expensive models but......

The Farm Track video is fun to watch and dream.

 

[4570Man]

One cannot properly compare a wood lathe to a metal lathe! You may tap with your metal lathe, and require extremely low speeds. On a wood lathe, if you need extremely low speeds, you'd better balance that big knot or whatever you are turning! Or get a bowl lathe.

I know the difference, but the point was gear monsters win at low end toque. A tesla is comparable HP to a semi ( the tesla is more if my memory on the specs is correct. Any bets on which one puts more toque to the ground? The bet wasn't a race, but a toque wrench on the hub.

 

[vvanders]

I had a great experience Thanksgiving day with EV autos. I got to ride in a Tesla S P100D and that changed all my doubts about electric vehicles of ANY kind. Quiet an experience for an ole country boy as myself. I've always been intrigued with electric motors and electric autos and I could see direct drive with the 3 phase motors such as Tesla uses. The Tesla has (2) 3 phase motors, one front and one rear and is 4 wheel drive with traction control. There would be no use for a transmission of any kind using a high tech motor controller such as the Tesla. The batteries and cooling system make the Tesla heavy as mentioned by CincyFlyer 5000 + lbs. I'm not sure how they do the 4 wheel drive but would like to find out what type of differential or whatever apparatus is used.

From a dead stop you'd better push your head back into the head rest before accelerating because it is some more fast. The range doing average driving is somewhere around 300 miles on a charge. I'm not sure how that would relate to a tractor's task but at $130,000 (Tesla's price) I'll never find out. They make lesser expensive models but......

The Farm Track video is fun to watch and dream.

They use an open differential that has an electric brake controller to limit wheel slip, along with sub 1ms torque control thanks to the 3-phase motor.

It's pretty darn impressive. I can slam the throttle on our 85D in the rain and doesn't even step out an inch.

I'd love to run an electric tractor, stop & start is basically the bread and butter of an EV as you don't have any idle to worry about and all the torque is down low. No tier IV emissions, no tranny aside from maybe a 4x4 transfer and you can run the PTO completely independently based on if you want to use a second 3-phase motor for it.

20kW battery would probably be fine, and the extra weight is probably a benefit as well.

 

[Steave]

They use an open differential that has an electric brake controller to limit wheel slip, along with sub 1ms torque control thanks to the 3-phase motor.

It's pretty darn impressive. I can slam the throttle on our 85D in the rain and doesn't even step out an inch.

I'd love to run an electric tractor, stop & start is basically the bread and butter of an EV as you don't have any idle to worry about and all the torque is down low. No tier IV emissions, no tranny aside from maybe a 4x4 transfer and you can run the PTO completely independently based on if you want to use a second 3-phase motor for it.

20kW battery would probably be fine, and the extra weight is probably a benefit as well.

Thanks for the infomation. Except for the price I don't see many downsides to an electric tractor. I agree with you I'd like to drive one.

The S model didn't spin a tire either just took off like a rocket but a bit odd not hearing any noise. Rolling at 35MPH then slamming as you said I did feel a slight spin of the tires but hardly noticeable but I wasn't driving either.

Even though I wouldn't need ear protection I still would have on my headset for jamming but I could turn the volume down. Naaa what am I thinking.

Another good point would be no antifreeze, no warm up (which wastes a lot of fuel), no oil changes (messy job), and a host of other good points too many to list.

 

[/pine]

I have not followed the development of EVs other than state of the art golf carts...Textron/EZGO introduced the 3 phase AC electric cart in 2008...
One thing I have learned about EVs is...the larger the diameter of the wheels the less torque you have...more speed but less torque...not sure how that will apply to tractors that usually have large dia. rear wheels?

 

[vvanders]

Thanks for the infomation. Except for the price I don't see many downsides to an electric tractor. I agree with you I'd like to drive one.

The S model didn't spin a tire either just took off like a rocket but a bit odd not hearing any noise. Rolling at 35MPH then slamming as you said I did feel a slight spin of the tires but hardly noticeable but I wasn't driving either.

Even though I wouldn't need ear protection I still would have on my headset for jamming but I could turn the volume down. Naaa what am I thinking.

Another good point would be no antifreeze, no warm up (which wastes a lot of fuel), no oil changes (messy job), and a host of other good points too many to list.

Yeah, you still do have a coolant loop(proper thermal management is key to battery life) but oil changes aren't a thing, although you'd still probably have hydraulics to deal with.

 

[vvanders]

I know the difference, but the point was gear monsters win at low end toque. A tesla is comparable HP to a semi ( the tesla is more if my memory on the specs is correct. Any bets on which one puts more toque to the ground? The bet wasn't a race, but a toque wrench on the hub.

We had a thread on the Tesla semi a while back before it went off the rails and got shut down(much like I expect this one will given the last 2 EV threads went that direction).

At 80k gross it sounded like an electric based drivetrain was able to put a lot more torque down(if I recall 0-60 in 20s vs 60s). We'll see what it does when they start showing up but but based on the torque curve of 3 phase motors I don't doubt that it will be a torque monster.

 

[ericm979]

One thing I have learned about EVs is...the larger the diameter of the wheels the less torque you have...more speed but less torque...not sure how that will apply to tractors that usually have large dia. rear wheels?

There'll be reduction gears between the motor and wheels. Like the final drive in our diesel tractors. We don't need a 155 mph top speed.

I really like pistons, valves etc. but electric makes a lot of sense for tractors.

 

[bcp]

Slightly related information on electric motors:

An article comparing a locomotive's modern computer-controlled AC traction motors to the old style DC motors. A small, lightweight AC locomotive is able to outpull a much larger DC locomotive. Power is from a diesel generator instead of a battery, but it is delivered to the wheels by electric motors.

AC Traction vs DC Traction - Greenville, South Carolina - Republic Locomotive

Bruce

 

[MHarryE]

Caterpillar has been selling its electric D7E dozed for several years. Granted electric power is generated by its on board 250 HP diesel but with the 480v AC electric system they advertise 35% improved fuel economy vs the D7R power shift mechanical drive. At Cat we blew away the older inefficient electric drive mining trucks with our mechanical drive trucks but electric drive improvements have us now selling both electric and mechanical drive versions. Still diesel engine power generation because of 24/7 operation. Mining would like to get rid of the diesels because of cancer and other health related issues due to diesel emissions collecting in large holes in the earth typical of mining but more is being done on atonomous operation and doing away with drivers to solve the diesel emission health problem.