I am building a dark ride at my house for a party (long story), where the I have a ride vehicle that is a wooden base with 4 casters and 2 powerchair motors hugging a center 2x6 rail on a plywood base for track. The center rail has a power bus - a strip of metal on each side for power. This all works great in a giant loop. I have multiple 24VDC power supplies connected in parallel around the track.
However, now that I have one car happily going around and around, I need to cut the center rail bus in places to make "zones" so I can add and control multiple cars at once. There will be a PLC programmed, with track sensors as input and as output a PWM to a motor controller for each zone. That allows me to control the speed in each zone differently (go fast in some cases, go slow for slowly seeing scenes in another, and STOP at the two train stations). Fast may be 24VDC, Slow 18VDC, and Stop 0VDC as examples. Slow may vary.
Here is a link to the actual motor controller:
So to repeat, I have multiple 24VDC 40A power supplies. Each one is located next to the track in different places by their respective "zone". The motor controller is connected to the power supply and the output of the motor controller is connected to the track "zone" itself. Each car on the track uses 10A while driving flat and straight and can go up to 19A when going around curves or uphill.
So HERE'S THE CRUX: If the ride vehicle crosses zones, the brushes on the vehicle that brush the center rail strips will briefly touch the strips on BOTH zones, the one it's leaving and the one it's entering. If both motor controllers are set to say 50% (12VDC), it's no concern, seems to be fine. However, I haven't tested it when one zone is set to 24VDC (full) and another say 0VDC (zero). I'm concerned about back-biasing the 0VDC motor controller. Now the motor controllers are designed to handle 60A at 24VDC (the capacitors and transisters etc.) so I am not sure if it's really a problem... and I don't see how I can solve the problem with diodes either (such as when you connect two power supplies in series).
The amount of time the brushes will be connected across two zones will be brief - maybe a second at the most???
Any help would be appreciated - I have 9 zones and I don't want to let the magic smoke out!
THANK YOU! FYI I am a cross between knowledgeable and a newbie - decent at TTL electronics etc. but not high current applications.