Putting it back together

After a minor panic with the motors running like a pork chop on the test bench, the problem turned out to be mis-connected hall-effect position sensors that go between the motor and controller. Once hooked up correctly, the motors spin smoothly and quietly in both directions.

So it's time to put back together.

First the arms, wheels and the controllers.

Now with the 4 x 12v batts in place. All 240Kg worth.

Controller temporarily hooked up with speaker cable - I didn't want to go chopping up heavy-gauge wire until I was sure about how things would be routed and what lengths were needed.

Detail of the connection between the motor and wheel gearbox.

The motor mounts will get more paint and eventually a cowling to keep the weather off.

My test control box. The joysticks are 1-axis units made by Apem.

More temporary wiring...

And the main contactor with a pair of precharge resistors across the terminals to chanrge up the controller's capacitors so as not to incur a high current surge when the contactor is closed.

The contactor is rated at 400A. That looks to be possibly a little over-specced, as the unit looks to use about 10-40 amps when travelling, but I'll need to do more testing to find out what the range really is.

Again, this is a temporary install. Once everything is working properly I'll locate it in a more protected position and wire it up nicely.

Motor Problems

Well, I got everything hooked up on the bench, and it all works, kind of. It's *much* noisier in reverse, and seems to draw a lot more current than when going forward.

However the big problem I encountered was the motor randomly stalling. This most often happened when trying to reverse the motor. I swapped the controllers with the same result, then I tried the other motor - it wasn't as bad, but still often happened when engaging reverse. The motor simply won't move, despite the clamp meter showing 200A going in to the motor (I've got the controller limiting the motor current to 50%).

Usually engaging forwards will get the motor to spin, but with the first motor I tried, it was possible to have the motor stalled in both directions.

This is a serious concern, as at the moment there's virtually no load on the motor - just the gearbox - I'd hate to think how bad it'll be when it has to move the machine. This can't be normal...

Video below - the first part shows the setup, the stalling issue is at about 1:25

Motor Mounting

So my Kelly controllers and motors have arrived. In the mean time I've taken the side arms off the chassis and painted them, as well as painting the gearboxes. Now it's a matter of getting some idea how the motor and gearbox will line up.

The right side arm and gearbox are upside down on the bench.

The laser helps line things up.

I'm using universal joints to hook things up. A favour from another kind neighbour (not the ones who donated the machine) results in some short drive shafts with keyways each end.

The motor mount isn't the most complex thing. It's just tacked in place for the moment.

And drive shaft hooked up.


Now it's a matter of wiring up the motor and conrtoller and seeing how she goes!