Well, here's the finished article, not very pretty but it was only made to illustrate the Thomas method of dividing the power from the engine and sending it along two paths to the wheels.
You can see the drive going into the top diff, with the left hand drive shaft turning the generator and the right hand drive shaft driving the right hand wheel via a chain. The motor on the lower diff has a square end on the armature where the brake was fitted, initially I was going to fix the chain drive to that but the diff ratio is so low and easy to turn that the upper diff would have had nothing to work against to drive the generator fast enough, so I figured if I took the chain drive to the wheel it would give it the resistance it needed. When it was going I could stand on the frame and it would carry me around on a paved area, I was quite pleased with it.
Here's a pic of the contraption today, it's a bit dirty as I made it back in 2008, the year before the missus was diagnosed and it's been in the shed ever since.
Here's the switches to connect the generator to the motor.
Here's how it works, with the engine running the right hand wheel holds the right hand drive shaft still, so the diff turns the left shaft twice as fast, spinning the generator freely. When the generator is connected to the motor via the switches, two things happen.Whilst trying to move the machine the motor on the axle draws current from the generator making it act as a brake on the left drive shaft, causing the diff to start transferring torque to the other drive shaft and turning the right hand wheel.
If you imagine the pic of the old truck I put up at the beginning, the power from the right hand side of the top diff would go via the chain to the truck, and the current from the generator driven from the left side would go to the trailers. If the truck slowed down the generator would speed up to power the trailers more to help the truck pick up speed.
Think I've got it right, hope so.
Wee-Allis, you were spot on.
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Here's another application of the transmission, this time in an RM class railcar of the New Zealand Railways in 1916.
It was powered by a Tylor 200hp V8 driving the front bogie mechanically and the rear bogie electrically using a Thomas transmission.
Maybe Roderick can shed a bit more light on it?
Looks a fair size engine
I like the fire extinguisher
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