E12 Puller

dh1

dh1

Electric Tractors . from Markham Ont. Canada
Staff member
Moderator
I have s GE garden tractor model E12,
Had it for a while now and decided to.make it s pulling tractor.
The idea is to use 2 snow blower motors, 2+1/2hp each, feed them with 72volts, originally ran at 36volts. Use a chain drive and take it to the pulls.
I have moved the front axle forward.
Hade a hub modified to mount 2 sprokets on it.
Shortened the rear of the frame to move the hitch closer th the rear axle.
And widened a set of rims for
26-12×12 tires.20190412_192610.jpg
 
dh1 said:
Motors are identical and wired in parallel.
Motors will run at full power for 30 seconds or less, I think they be ok.
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No way of easing of the start line..? Just flip a switch and go.? Not sure if I'm following..
 
Toomanytoys84 said:
I've seen tens of thousands dollar spent to get two identical dc motors to load share properly. Without proper control they will fight each other.
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Ever seen a freight train with 3 or 4 engines on it, or even 2 on point, one in the middle and two running DP? They are not running exactly the same amount of torque but they run that way half way across the country and back several trips and no issues. They all share part of the load but not equally.

Or how about a vehicle stuck in the snow, can't move but two guys help by pushing on it get it out. No equality of power there either but it works.
 
chieffan said:
Ever seen a freight train with 3 or 4 engines on it, or even 2 on point, one in the middle and two running DP? They are not running exactly the same amount of torque but they run that way half way across the country and back several trips and no issues. They all share part of the load but not equally.

Or how about a vehicle stuck in the snow, can't move but two guys help by pushing on it get it out. No equality of power there either but it works.
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That's not an apple to apple comparison. You have 2 motors mechanically locked together.

You have 2 DC motors wired parrell Connecting them in parrel voltage will be the same but current will be shared between the two motors.

I'm no electrical engineer but I have worked on many multi motor belt drives. One motor is set up as the master motor the rest as slaves. The master says to the other motors ok guys I am going to be running 3600 rpm you guys need to help keep me there.

I don't believe a dummy curtis motor controller is going to manage that.

Also worked on DC locomotive with a 100hp drive motor on each end. Controlled with a saminco drive. When this was in development one motor would do all the work and the other motor just sat there basically doing very little. It took people much smarter than me to get the two motors to work together and share the load.

I'd say the end result of this is that one motor will burn up. Not immediately but over time one motor is going to be taking the load.
 
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Aaron I can see that happening in parallel? When we ran conductors in parallel they had to be almost exactly the same length or one set would try and carry the whole load. If one of your motor shows more resistance than the other I would think things might get a little toasty.
Really hope dh1 carries through with this project and proves us wrong. This is what makes projects like this so interesting.
 
Cvans said:
Aaron I can see that happening in parallel? When we ran conductors in parallel they had to be almost exactly the same length or one set would try and carry the whole load. If one of your motor shows more resistance than the other I would think things might get a little toasty.
Really hope dh1 carries through with this project and proves us wrong. This is what makes projects like this so interesting.
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I don't want anyone to think I am trying to put down his project. I'm just throwing in my 2 cents on what I think.

I'm all in for innovation and trying to build something new and cool!
 
I have a 36volt 200amp controller.
My idea if I can get it to work, is to run with the controller at 36volts to move the tractor around and start the pull, once I get going and I feel the tractor start to slow down a bit I hit a switch that turns on a contactor, bypasses the controller and applies 72 volt direct to the motors and run till the tractor stops.
Each motor will get 72volts and draw what every they can and what ever the batteries can deliver.
These motors came with a 105amp circuit breaker, I expect then to draw double that or more.
So 105 x 2 = 210
210 × 2 (motors) = 420amps in theroy if I'm right on this. ???

Now I'm working on the hitch and wheelie bars.
 
dh1 said:
And all comments are welcome here as this is what makes it fun a challenge to see if it can be done.
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I'd like to see a picture of the controller you're thinking of using... :thumbs:
 
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