Quote:
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.
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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.