MoTeC Global Forum

Hello.

I am in the process of refining the pdm file on a rally car that I helped build. I am not sure how to set up the two fuel pumps, as I have a main pump and a spare pump. Both are plumbed in and wired in as well. Right now I have the main pump set up and running.

My question is how would I write the logic to turn off one pump if it draws too much, and turn the other pump on in that case so the car does not stop on stage??

Thank you as always..

Scott.

There is probably a large number of different ways of doing this depending on how "automatic" you want the switch over to be and what fail safes you want etc.

You could simply have a switch that determines which pump runs, so if one fails the driver/codriver flicks the switch and the other pump will run.

To make it switch over automatically you need to take a few things into account. Firstly, you only want the second pump to come on if the first one has failed, not just turned off. Secondly, you want it to change over both when the pump over currents or draws no current. Below is an example config I quickly threw together of a way that you could do this. It is a rough brain dump of how it might work, I haven't tested this at all (even on the bench), so if you use this method you will have to test it out thoroughly.

The most important thing with this is making sure there aren't any corner cases where the second pump turns on when you don't want it to. Obviously this could cause a serious issue.

Great example! Thanks, Adrian!

--Peter