|
First off, I apologize for giving such a vague post, when 'thingstodo' posted such an informative and inquisitive reply.
Let me start over.
I have the P&S control board, but instead of the mosfet driver on the board, I run that into dual IGBT drivers. The IGBT drivers drive 6 400A IGBTs. I've derated this to 1200A. Surface mount hall effect sensor, with enough spacers so that the control board sees 511A when the actual motor current is 1200A, roughly. I've got another similar controller running 4x400A IGBTs.
This setup has worked extremely well. About my only issues was some cold solder joints where I was tacking on wires to Paul's beautiful control board.
I've been running this for a few years. This is in a custom pulling tractor. 135V x800A of headway cells. Used to be 170V but I keep losing them. 31x15.5-15 tires. 1900 pound class. 13" series motor chain driven to a ford ranger rearend. Was about 1:1 chain ratio to a 5.13:1 ring/pinion.
About a month ago, I was on a pretty good run, and at the end of the track the rear started clunking. Broke a few teeth off of the pinion gear. I replaced the 5.13:1 setup with a 3.55:1 gear, as thats the quickest/cheapest thing I could find. Changed the sprockets and ended up with a little bit faster final ratio.
Also somehow related, my forward/reverse contactor setup to switch the motor field welded in the forward state. Something must have surged or to weld that contactor AND break the rearend.
Anyways, slapped it back together to compete the next week, and try to stay in the points chase. Tractor took off then then falls flat. I didn't have the computer hooked up, so don't know the details. Did the very same thing the next day. So during the week I took out the forward/reverse contactors. Thought that may have been causing problems or a severe power loss.
Next event, same thing. Next day, finally hooked up the laptop to get a datalog. This time I observed full 511A motor current, but I've limited it to 300A battery current. So the PWM was only like 50%. Then after around one second, the PWM went to 100%, and current bounced around, as observed on the datalog. But in reality, the power just fell flat.
Now know that 511A motor current is actually like 1250. Previously, over the years, I had only seen about 1100A max.
Well, open opening up the controller this morning, I found the VR1 pot was set all the way CCW. So seems like hardware overcurrent protection would come into play if I'm pushing it all the way to 511A, although it may not work exactly like it was originally designed? Power absolutely fell off, and current on the datalog was funny and bouncy.
RECALL that I ended up gearing it a little bit faster than before, so it would logically see more amps than ever before.
So I think I'll turn up the hardware protection, and changing gearing to keep it more inline. That hopefully will do the trick.
|