Elevator Design Help

[asid61]

Originally Posted by grem110

Thanks for all the advice! We will definitely reduce the diameter of the spool. I assume that keeping the worm gear for its anti-backdrive ability is a must? I ran some numbers and discovered that using an RS-775-18 with a 35:1 reduction would work pretty well--I may have forgotten to mention we have a block and tackle pulley system that acts as a 2:1 reduction, so the system would have an overall 70:1 reduction.

Also, how does amperage fit into all of this? Not sure how much amperage to give this motor when I still want to have the robot drive and grab the totes (grabber is motor driven).

Thanks so much for everyone's help.

If you use the jvn design calculator it makes all this calculation much easier. According to that, you are running 38 amps when you are lifting 70lbs- a lowish estimate for claw + totes + bin. However, when you factor in efficiency and random junk getting in the way, you should be gearing it down even further, maybe with a second 2:1 reduction to make your overall reduction 140:1.
That nets you a speed of 1.7ft/sec and has a big margin of safety.
Now, you still have to use a worm gear to prevent backdriving, as braking with an RS-775 alone may cause a fire. We added a bike brake to our lift to stop it, and that works wonderfully. There are specs online for where to mount a disc brake if you choose to go that route.
You can use a 70:1 reduction if you run a cim, as that will only draw 21 amps at max load and give you a max loaded speed of 1.6ft/sec. I do not know how slow you would have to run if you choose to brake with the motor alone.