(this is a repost from comp.home.automation). Thanks.
My dad and I built a homemade hill lift (in Europe refered to as funiculars) in Eastern Tennessee. You can see a working demonstration and picture of it at:
The tram works fine, but I am trying to figure out some kind of simple safety mechanism in the event that the spools break loose from the gearbox or shaft and start rotating freely. Since my wife and kids ride this thing, I'd like some kind of backup solution in the event of major catastrophe. We are using 2 cables instead of one even though one can handle 5 times the max load, and we have a braking motor to stop, but both of those would be moot if the spool spins out of control.
I am thinking of having some way of measuring the outfeed speed of the cable (or spool) and have some emergency brake apply if a limit is exceeded.
Any suggestions? I thought about putting fan blades at end shaft of the spool to have air slow it down, but that would be a little unsightly. I'm looking for a simple solution, one preferably without a
computer since this is outdoors and needs to be functional 100% of the time.
Thanks in advance. Jeff