Yes, I agree with the words below. I better way to measure torque is to make a drumwrape a cable around it and lift a bucket. Run the drum at different PPMs and load the bucket until the drum slows from it's programmed RPM. THis will allow you to plot an RPM vs torque curve.
What you have with a torque wrench is only one point on that curve. For a stepper motor this is the "best case" point on the curve, all other points would be lower. Static torque is important but mostly these drives are meant to move. Along to same line. Measuring longevity under zero load is not as interesting as if measured at say 50% of max torque and running it in both directions. I know, testing takes time. That said, I'm watching these experiments closely because I want to make some of these reduction drives myself. I meed at least 100:1 reduction in a very smallspace. I want to use a motor like one of these (but likely notthis exact one) amazon.com/Hobbypower-1000kv-Brushless... <https://www.amazon.com/Hobbypower-1000kv-Brushless-Multicopter-Quadcopter/dp/B00E7LG85O> The "1000 KV" means 1000 RPM per volt and it comes with a digital controller. I Would mount the motor almost inside the flex cut of the harmonic drive and maek an effective 10KV motor system On Mon, Sep 13, 2021 at 10:26 AM John Dammeyer <jo...@autoartisans.com> wrote: > Nice update. > My math works out as follows: > 35 lb-ft is 35 * 12"/ft * 16 oz/lb = 6720 oz-in. > You said the ratio is 100:1 so that means to get 6720 you only input 67.2 > oz-in. That's about 1/3 of what you suspect your motor can do. > > Something is wrong with this picture then. Especially since you were > effectively using static torque rather than the much lower torque when the > motor is turning at say 400 RPM. With micro-stepping you also get a > reduction in full step torque because the max current is now 0.707 x full > torque. And without closed loop encoder feedback you can quite easily have > to micro-step a number of times before you see physical motion. > > None of that matters other than that you have shown your mechanics can > handle 35 lb-ft which is all in all pretty cool ! > > John > > > > > > -----Original Message----- > > From: Sam Sokolik [mailto:samco...@gmail.com] > > Sent: September-12-21 5:50 PM > > To: Enhanced Machine Controller (EMC) > > Subject: [Emc-users] Minimally printed rotary. Initial torque testing.. > > > > Small update > > > > https://youtu.be/eW1GGI55Epc > > > > _______________________________________________ > > Emc-users mailing list > > Emc-users@lists.sourceforge.net > > https://lists.sourceforge.net/lists/listinfo/emc-users > > > > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
