Warning: motor phase B may be disconnected reported by driver0
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Hi,
I keep getting this error/warning
Warning: motor phase B may be disconnected reported by driver(s) 0
I have atached a nema17 stepper motor and configured it to have
M92 X3200.00 Y200.00 Z200.00 E420.00 ; set steps per mm M350 X2 Y16 Z16 E16 I0 ; configure microstepping with interpolation M566 X50.00 Y900.00 Z12.00 E120.00 ; set maximum instantaneous speed changes (mm/min) M203 X6000.00 Y6000.00 Z180.00 E1200.00 ; set maximum speeds (mm/min) M201 X20.00 Y500.00 Z20.00 E250.00 ; set accelerations (mm/s^2)Only X motor is connected. The motor is rated for max 1.5A and I tested with all kind of settings between 1 and 1.5
This motor is driving a leadscrew with 1mm pitch
So I define it as 3200 steps per mm (based on the default 16x microstepping on duet) and then reconfigure for x2 halfstepping without interpolation (It does the same if I choose x16 I1 howeverAs soon as I let my motor reach 900rpm . (resulting in 15mm/s speed on my leadscrew) I start getting these warnings.
I can however go a lot higher than 900rpm on the motor and it doesn't stall, but what are these warnings and what should I do with them ?Are they any indication of step loss? Or is this some kind of bug ?
Kind regards,
Bart -
is the inductance for the motor known? and what is the supply voltage and which board do you have?
ofcourse also; you're sure the wiring is good and strain relieved at the connectors?
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Inductance is 4.8mH± 20%
Supplyvoltage is 24vDC
Wiring is factory wiring and I tried 4 identical motors which makes me think they won't be all faultyAny idea ?
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Not my strong suit, just wanted to let the wizards have the relevant information. Maybe try the other driver outputs while the clever people spot the thread (power off before moving the motor connector to reduce risk of toasting drivers)
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please plug in your motor values in the emf calculator
https://www.reprapfirmware.org/
with an inductance of 4.8 m.H you are pretty much at the max speed for that motor with 3200 steps/mm
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I tried that EMF calculator and indeed I see that when I go past 15mm/s (which is 3200steps per mm) then I and get red numbers
It also looks like microstepping has nothing to do with it and also that running the motor at 1A lets me achieve higher speeds than running is at 0.5A (under the condition that the motor can produce enough torque of course)
So now what ? Any suggestions for quality motors which have lower inductance and could give me higher speeds ?
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@educa said in Warning: motor phase B may be disconnected reported by driver0:
I tried that EMF calculator and indeed I see that when I go past 15mm/s (which is 3200steps per mm) then I and get red numbers
It also looks like microstepping has nothing to do with it and also that running the motor at 1A lets me achieve higher speeds than running is at 0.5A (under the condition that the motor can produce enough torque of course)
So now what ? Any suggestions for quality motors which have lower inductance and could give me higher speeds ?
What is the model number of your existing motor; or failing that, its size (including length)? is it 1.8deg or 0.9deg?
3200 steps/mm (@ x16 microstepping) is very high for the X axis of a 3D printer. Maybe OK for a CNC machine where greater force is needed and lower speeds are acceptable. Perhaps you should change to a leadscrew with a lead higher than 1mm?
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The current motor is a kysan 1124090 with 4,8mH inductance and 2,8 ohm resistance
I can reach around 13mms on my leadscrew with 24vDC and I can even achieve this while powering the motor with only 0.2A while the motor is rated at max 1.5A
So the motor is too powerfull for what needed.
I tried the EMF calculator (didn't even know this existed) and found out that lower phase inductance can lead to higher speeds.
I cannot us other leadscrews because I bought second hand THK KR20 rails which are ultra high precision screws at quite high price
So I have to stick with them and I have to find motors with lower inductance if I want higher topspeeds. I'd like to be able to reach 20mm/s if possible because the printer I'll make for this won't go faster than that.
Anyway, The motor I'll need probably can we nema 17, but also nema 14 or even 11 since I am perfectly able to run it at 24V 0.2A currently, so there is margin.
Any idea where I could find motors specificly suited for higher speeds and having lower inductance ? I have 1 goldenmotor nema11 here (model 28HD1411-02) and that motor should have 4,8ohm resistance and 2,8mH inductance, so this one should go faster.
Any tip/shints are welcome
If you do it, do it good.
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How about these https://www.omc-stepperonline.com/nema-17-stepper-motor/3pcs-of-nema-17-bipolar-45ncm-64oz-in-2a-42x42x40mm-4-wires-w-1m-cable-and-connector.html. More torque than you need, but only 2.8mH inductance and 1.1 ohm resistance.
Most Nema 14 motors have low rated current, which unfortunately also means quite high inductance.
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@Veti said in Warning: motor phase B may be disconnected reported by driver0:
1.8mh
That's a 0.9deg motor, so using it would be a very bad idea in this instance. Is there a 1.8deg version with similar characteristics?
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@Veti said in Warning: motor phase B may be disconnected reported by driver0:
That one looks good! @educa, try plugging the values for that motor into the calculator, with the actual current set to 1.5A.
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If I plug this one in the calculator (and I enter 2500mA rated and 1500mA given current @ 24vDC, then this motor should theoretically give me 28mm/s before things go red
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I wonder what the back EMF due to rotation is based on. For this last motor that seems so be the limiting factor and not the inductance. It seems like it is related to the Rated holding torque so I guess thats as good as it will get for that motor (if 28 mm/s is the calculated limit, then maybe 25mm/s would be a safe limit and that is a very acceptable speed for what I want to build
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I think I found one who will even go faster. he has a little higher inductance, but half the holding torque.
I can move my axis perfectly fine with only 0.2A on the current motors which are rated at 1.5 , so I require very little force.
Chances are big that this motor will have enough juice to move the axis and will also be able to go faster in the end because if reasonably low inductance EMF, but due to the lower holding torque also more margin in the EMF due to rotation of the motor
https://www.omc-stepperonli
ne.com/hybrid-stepper-motor/dual-shaft-nema-17-bipolar-1-8deg-22ncm-31oz-in-1-33a-2-8v-42x33mm-4-wires.html -
@educa said in Warning: motor phase B may be disconnected reported by driver0:
I think I found one who will even go faster. he has a little higher inductance, but half the holding torque.
I can move my axis perfectly fine with only 0.2A on the current motors which are rated at 1.5 , so I require very little force.
Chances are big that this motor will have enough juice to move the axis and will also be able to go faster in the end because if reasonably low inductance EMF, but due to the lower holding torque also more margin in the EMF due to rotation of the motor
https://www.omc-stepperonli
ne.com/hybrid-stepper-motor/dual-shaft-nema-17-bipolar-1-8deg-22ncm-31oz-in-1-33a-2-8v-42x33mm-4-wires.htmlI use the single shaft version of that motor in one of my printers. It will have more than enough torque for your printer. Plan on 0.8A current.
