Motor movement issue
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My motors type is ACT Motor Nema17 Scrittmotor 17HS5425L20P1-X2 and this is what the calculator told me
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Approximate peak back EMF due to rotation per motor: 3.2 V at 150.0 mm/s
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list itemApproximate peak back EMF due to inductance per motor: 0.7 V at 150.0 mm/s
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list itemStep pulse frequency: 12.0 kHz at 150.0 mm/s
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list itemSpeed at which torque starts to drop (low slip angle): 212.0 mm/s @ 24.0 kHz
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list itemSpeed at which torque starts to drop (high slip angle): 278.3 mm/s @ 31.5 kHz
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Two observations:
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You are running the motors at less than 50% of their rated current (1200mA). Try higher, e.g. 1800mA or even 2000mA. Then re-run the back emf calculator.
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What VIN voltage are you using? If it's 12V and the calculator indicates that the torque will start to drop at too low a speed, changing to 24V will help.
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I tried wir 2.2A Motor Current. Motors run a bit hot during print. Wasn‘t diffrent.
Also, I tested diffrent motors w/o changing the issue.Next week I will get a new Power Supply with 24v to change the whole system to this voltage.
I will reply my experience
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@computiger said in Motor movement issue:
Motors doing stops during G0 and faster G1 (90mm/s). Stops are not at same position by different movements and the position after movement is exact.
Perhaps I misunderstood the problem. Can you explain exactly what you meant?
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ok, i try to explain again. Hope my english is good enough.
If my carriage moves in x or y direction with 150mm/s or less speed than carriage isn‘t run in constant speed. The carriage starts to stutter.
I tried other motors with less current but I got the same issue.I am using steel rods with misumi bearings. W/o motors I can move the carriage easy in all directions.
Can it be a issue of the power supply? Maybe a voltage fluctuation?
With my 2nd DuetWifi on an AM8 I didn‘t have this issue. Printer is running with 12V as well.
Doesn‘t matter, I will change my system to 24V and MGN12 linear rails during next weeks.
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@computiger said in Motor movement issue:
Can it be a issue of the power supply? Maybe a voltage fluctuation?
Yes, it could be. After you see the motors stutter, run M122. In the report, look for the maximum and minimum VIN voltage and the number of under-voltage events.
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Good to know, thanks David
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It isn´t the Power supply, values look stable
M122 shows me:
Supply voltage: min 12.2, current 12.4, max 12.5, under voltage events: 0, over voltage events: 0How I said, I´ll change the system to 24V and MGN Linear rails
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I found my problem. My motors are ok.
After I renewed my mesh bed level settings, motors could run more than 300mm/s w/o any stutter. -
@computiger said in Motor movement issue:
I found my problem. My motors are ok.
After I renewed my mesh bed level settings, motors could run more than 300mm/s w/o any stutter.Enabling mesh bed compensation can cause moves longer than the mesh spacing to slow down at the segment boundaries if the Z jerk is set too low.
