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bigtreetech / BIGTREETECH-S42B-V1.0

The closed-loop drive is to feedback the rotation angle of the stepping motor to the control panel, compare the distance that needs to be rotated with the distance of the actual rotation, calculate the error value, and then compensate, so as to prevent the problem of multi-step and lost step. The closed-loop drive can completely overcome the lost step of the open-loop stepping motor, and can also significantly improve the performance of the motor at high speed
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motors loud/screeching #26

Open lousassole opened 3 years ago

lousassole commented 3 years ago

I am at a loss here. I have installed these drivers/kits on my x and y axis, and on both axes when holding position they emit a loud whine. When moving it becomes more of a screech. I have tried loosening my belts, which did not help much. I have ensured the voltages are correct as well, and that everything is mounted flush. The printer still runs well, the screeching is nearly unbearable though. Is there anything i'm missing that fixes this?

Quas7 commented 3 years ago

do you have a datasheet for your nema17 motors? E.g. the inductance, resitance and current rating? And what supply voltage do you use for the S42B (12V or 24V?)

lousassole commented 3 years ago

Brand: Creality 3D Item name: RepRap 42 Stepper Motor Item number: 42-34 Step angle: 1.8 degrees Nominal Voltage: 4.83V Current Rating: 1.5 (A) Rated speed: 1-1000 (rpm) Rated torque: 0.4 (NM) Ambient Temperatuar: -20℃~+50℃ Length: 34mm

The printer runs off 24v, mainboard is a BTT SKR 1.4 turbo on marlin 2.0.x bugix they are the default x/y motors for the ender 3. As far as i'm aware, they should be compatible.

Quas7 commented 3 years ago

ok, and changing the motor current does change the screaming frequency? I had loud motors only, if I wired the phases incorrectly (A1,A2,B1,B2 S42B output but some motors are A1 B1 A2 B2 input). But with wrong wiring they should move very erratic and you get successfull prints, right?

lousassole commented 3 years ago

prints are successful (even had a successful 16hr job last night), and changing voltages seems to have no effect as far as i can tell. It seems to be that whenever there is any strain placed on the axle of the motor and it has not been disabled, it produces this screeching sound.

Quas7 commented 3 years ago

I think, your motors are a bit on the high side with their inductance (>7mH maybe). The required voltage to drive 1.5A is quite high which means there is more wire with its series resistance on the motor coils and this results in a higher inductance. High inductance makes motors reluctant to change direction (or accelerate) and that should hit the decay mode of the stepper driver stage and might result in audible noise. Normally, higher or lower supply voltage should change the pitch.

In other words, you could try nema17 with <4mH or just around 3V for 1.5A and around 40Ncm torque.

https://reprap.org/wiki/NEMA_17_Stepper_motor

lousassole commented 3 years ago

i'll play with the voltages some more. I'm trying to keep the motors as cool as possible though, so i may end up having to switch to a different motor.